Notice: The maintainers of the OBD-II Home Page provide this forum as a public service. In no
manner do we encourage disruption of the functions of the On-Board Diagnostic systems of any
vehicle to be used on the highways of our nation. If you are in any doubt as to your ability to work
within the framework of current EPA regulations, we urge you to have a qualified technician handle
your vehicle analysis and repairs.

The OBD-II Home Page is hosted by

http://www.autotap.com

For information on AutoTap, please call (815) 433 - 5100 or visit www.autotap.com

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OBD-II Background Information

OBD-II Background

What is OBD-II?

Where'd it come from?

Why do we need it?

Does my car have OBD-II?

How do we measure OBD-II output?

What good does it do to measure OBD-II output?

Tell me about that "Check Engine Light".

OBD-II and your car's health

Proprietary Sensor Readings

OBD-II and performance tuning

What is OBD-II?

On-Board Diagnostic systems are in most cars and light trucks on the road today. During the '70s and
early 1980's manufacturers started using electronic means to control engine functions and diagnose
engine problems. This was primarily to meet EPA emission standards. Through the years on-board
diagnostic systems have become more sophisticated. OBD-II, a new standard introduced in the mid-'90s,
provides almost complete engine control and also monitors parts of the chassis, body and accessory
devices, as well as the diagnostic control network of the car.

[Back to top]

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OBD-II Background Information

Where'd it come from?

To combat its smog problem in the LA basin, the State of California started requiring emission control
systems on 1966 model cars. The federal government extended these controls nationwide in 1968.

Congress passed the Clean Air Act in 1970 and established the Environmental Protection Agency (EPA).
This started a series of graduated emission standards and requirements for maintenance of vehicles for
extended periods of time. To meet these standards, manufacturers turned to electronically controlled fuel
feed and ignition systems. Sensors measured engine performance and adjusted the systems to provide
minimum pollution. These sensors were also accessed to provide early diagnostic assistance.

At first there were few standards and each manufacturer had their own systems and signals. In 1988, the
Society of Automotive Engineers (SAE) set a standard connector plug and set of diagnostic test signals.
The EPA adapted most of their standards from the SAE on-board diagnostic programs and
recommendations. OBD-II is an expanded set of standards and practices developed by SAE and adopted
by the EPA and CARB (California Air Resources Board) for implementation by January 1, 1996.

[Back to top]

Why do we need it?

The Environmental Protection Agency has been charged with reducing "mobile emissions" from cars and
trucks and given the power to require manufacturers to build cars which meet increasingly stiff emissions
standards. The manufacturers must further maintain the emission standards of the cars for the useful life
of the vehicle. OBD-II provides a universal inspection and diagnosis method to be sure the car is
performing to OEM standards. While there is argument as to the exact standards and methodology
employed, the fact is there is a need to reduce vehicle emitted pollution levels in our cities, and we have to
live with these requirements.

[Back to top]

Does my car have OBD-II?

All cars built since January 1, 1996 have OBD-II systems. Manufacturers started incorporating OBD-II in
various models as early as 1994. Some early OBD-II cars were not 100% compliant.

to see

the dates OBD-II started being included on specific makes and models.

There are three basic OBD-II protocols in use, each with minor variations on the communication pattern
between the on-board diagnostic computer and the scanner console or tool. While there have been some
manufacturer changes between protocols in the past few years, as a rule of thumb, Chrysler products and
all European and most Asian imports use ISO 9141 circuitry. GM cars and light trucks use SAE J1850
VPW (Variable Pulse Width Modulation), and Fords use SAE J1850 PWM (Pulse Width Modulation)
communication patterns.

to see which cars use each system.

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OBD-II Background Information

You may also tell which protocol is used on a specific automobile by examining the connector socket
carefully. If the dash connector has a pin in the #7 position and no pin at #2 or #10, then the car has the
ISO 9141 protocol. If no pin is present in the #7 position, the car uses an SAE protocol. If there are pins in
positions #7 and #2 and/or #10, the car may use the ISO protocol.

While there are three OBD-II electrical connection protocols, the command set is fixed according to the
SAE J1979 standard.

[Back to top]

How do we measure OBD-II output?

Pre-OBD-II cars had connectors in various positions under the dashboard and under the hood. All OBD-II
cars have a connector located in the passenger compartment easily accessible from the driver's seat.
Check under the dash or behind or near the ashtray. A cable is plugged into the OBD-II J1962 connector
and connected to AutoTap or another scan tool. AutoTap is available in PC/laptop or a Palm PDA
versions. Other scantools on the market range from simple hand-held meters that display trouble codes,
up to a large console computer-based unit costing thousands of dollars.

[Back to top]

What good does it do to measure OBD-II output?

OBD-II signals are most often sought in response to a "Check Engine Light" appearing on the dashboard
or driveability problems experienced with the vehicle. The data provided by OBD-II can often pinpoint the
specific component that has malfunctioned, saving substantial time and cost compared to guess-and-
replace repairs. Scanning OBD-II signals can also provide valuable information on the condition of a used
car purchase.

[Back to top]

Tell me about that "Check Engine Light".

The service industry calls the Check Engine light on your dash an "MIL" or Malfunction Indicator Light. It
shows three different types of signals. Occasional flashes show momentary malfunctions. It stays on if the
problem is of a more serious nature, affecting the emissions output or safety of the vehicle. A constantly
flashing MIL is a sign of a major problem which can cause serious damage if the engine is not stopped
immediately. In all cases a "freeze frame" of all sensor readings at the time is recorded in the central
computer of the vehicle.

Hard failure signals caused by serious problems will cause the MIL to stay on any time the car is running
until the problem is repaired and the MIL reset. Intermittent failures cause the MIL to light momentarily and
they often go out before the problem is located. The freeze frame of the car's condition captured in the
computer at the time of the malfunction can be very valuable in diagnosing these intermittent problems.
However, in some cases if the car completes three driving cycles without a re-occurrence of the problem,
the freeze frame will be erased.

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OBD-II Background Information

[Back to top]

OBD-II and your car's health

Because of their investment in the equipment required, most repair shops charge a fee, some-times
substantial, to attach the scanning equipment and diagnose problems using the OBD-II system signals.
Home mechanics and small shop technicians have been restricted from working with these signals by the
cost and technical complexity of the equipment. With the introduction of more economical and user
friendly scanning devices, it is now practical for almost anyone to access OBD-II signals and use them for
their own testing and repairs.

Scanners vary greatly in their complexity. The best connect easily and use software to quickly and
automatically call up the OBD-II information. They should have recording ability so that data can be
collected during a test drive without distracting the technician driving the car. A system connecting to a
laptop or desk top computer provides expanded memory for data and the ability to export data to a
spreadsheet or graphing utility.

[Back to top]

Proprietary Sensor Readings

Though not part of the EPA's OBD II standard, the diagnostic read-outs used by dealership technicians
are also read through the OBD II connector. These service codes show you such things as knock sensor
operation, FI pulse width, ignition voltage, individual cylinder misfires, transmission shift points and ABS
brake condition. There can be over 300 readings available, depending on the vehicle manufacturer and
model. Vehicles vary in the readings they will support. Scanners vary widely in the number of these
signals that they can read. Some show just the basic OBD or OBD II signals, others show the full range of
service codes.

[Back to top]

OBD-II and performance tuning

While the vast number of drivers want nothing more than dependable, economical transportation, many of
us are looking to OBD-II for extra performance. Earlier on-board computer systems had chips that could
be replaced to adjust engine parameters for extra speed and power. While the OBD-II systems are sealed
and do not allow chip replacement, they do provide a real time data acquisition system that is useful to
tuners.

Power loaders can actually reprogram the performance parameters of the OBD-II system to accommodate
performance options. At the current time the number of models they can service is limited, but the range is
being extended. Be sure the person doing your reprogramming keeps the car in compliance with EPA
emission standards. As aftermarket manufacturers develop additional solutions, we will add their
information to our links.

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OBD-II Background Information

[Back to top]

For information on the AutoTap PC and PDA-based OBDII scan tool, visit

www.

autotap.com

[ OBD-II Home ]

The OBD-II Home Page is hosted by

http://www.obdii.com/background.html (5 of 5)27-08-2006 22:07:01

OBDII - On-Board Diagnostic's System - Does My Car Have OBD-II? The Connector and Communications.

Does My Car Have OBD-II?

All cars and light trucks built and sold in the United States after January 1, 1996 were required to be OBD
II equipped. In general, this means all 1996 model year cars and light trucks are compliant, even if built in
late 1995.

Two factors will show if your vehicle is definitely OBD II equipped:
1) There will be an OBD II connector as shown below, and
2) There will be a note on a sticker or nameplate under the hood: "OBD II compliant".

The Connector

Pin 2 - J1850 Bus+
Pin 4 - Chassis Ground
Pin 5 - Signal Ground
Pin 6 - CAN High (J-2284)
Pin 7 - ISO 9141-2 K Line
Pin 10 - J1850 Bus
Pin 14 - CAN Low (J-2284)
Pin 15 - ISO 9141-2 L Line
Pin 16 - Battery Power

Where is the connector located?

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OBDII - On-Board Diagnostic's System - Does My Car Have OBD-II? The Connector and Communications.

The connector must be located within three feet of the driver and must not require any tools to be
revealed. Look under the dash and behind ashtrays.

The Three Flavors of OBD II

While the parameters, or readings, required by OBD II regulations are uniform, the auto manufacturers
had some latitude in the communications protocol they used to transmit those readings to scanners.
Naturally, each felt they had the one true way, so we have three different OBD II communications
protocols in use.

The big scanner consoles costing thousands of dollars include the decoding software and firmware for all
three protocols in their units, making them universal. Less expensive units, for home or small shop use,
are usually customized for a specific communications protocol. Be sure the scanner you are using suits
the protocol of your car.

What Communications Protocol does my vehicle use?

As a rule of thumb, GM cars and light trucks use SAE J1850 VPW (Variable Pulse Width Modulation).
Chrysler products and all European and most Asian imports use ISO 9141 circuitry. Fords use SAE J1850
PWM (Pulse Width Modulation) communication patterns.

There are some variations among captive imports such as the Cadillac Catera, a German Opel derivative,
which uses the European ISO 9141 protocol. If you have first hand knowledge of other such variations,
please

send them in

and, together, we can build a more complete listing.

On 1996 and later vehicles, you can tell which protocol is used by examining the OBD II connector:

J1850 VPW--The connector should have metallic contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2--The connector should have metallic contacts in pins 4, 5, 7, 15, and 16.
J1850 PWM--The connector should have metallic contacts in pins 2, 4, 5, 10, and 16.

If your vehicle has this style connector, but doesn't have these pins populated, you probably have a pre-
OBDII vehicle. To add some confusion, even having the connector with the contacts shown above is not a
guarantee of OBD II compliance. This style connector has been seen on some pre-1996 vehicles which
were not OBD II compliant.

Information on Pre-96 Cars

A reader with the California Air Resouces Board provided this list of pre-96 OBD II engine
designations. Note that CARB recognizes engine series, rather than vehicle models, so the engine
designations are the true key, with the vehicle models provided as a courtesy.

California Air Resources Board List of
Certified OBD II Complying Engine Families and Models

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OBDII - On-Board Diagnostic's System - Does My Car Have OBD-II? The Connector and Communications.

Engine Family

Manufacturer

Model(s)

Fully Compliant?

1994 Model Year Certifications
RAD2.8V8GFEM
RFM3.8V8G1EK
RFM4.6V8G1EK
RMB2.2VJGCEK
RMB3.2VJGCEK
RNS2.0VJGDEK
RTY3.0VJGFEK
RTY2.7HGEEK
RTY2.42HGEEK
RVW2.8V8GFHM
RVV2.3VHGFEK

Audi
Ford
Ford
Mercedes-Benz
Mercedes-Benz
Nissan
Toyota
Toyota
Toyota
Volkswagen
Volvo

100
Mustang
T-Bird, Cougar
C220
C 280, S 320, SL 320
G20
Camry, ES300
T100
Previa, Previa All-Trac
Corrado
850 Turbo

No
No
No
No
No
Yes
No
No
No
No
No

1995 Model Year Certifications
SBM5.4V8GAEK
SCR2.0VJGFEK
SCR122VJG2EK
SCR2.0VJG2GK
SCR2.0VJGFEL
SDS2.0VJGFEK

SFM3.828G1EK
SFM3.8V8G1EK
SFM4.6V8G1EK
SFM4.6V8G1GK

SFM2.318G1EK
SFM3.028G1EK
SFM3.018G1EK
SFM3.028G1FK
SFM4.018G1EK
SFM4.6VJG1EK
SFM4.028G1EK
S1G3.8V8G1EK
S3G4.319GFEJ
S3G4.329GFGJ
SIG2.3VJG2GK
SHN2.7VJG1EK
SHN2.7VJGFEK
SHN2.5VJGKEK
SHN3.0VJGKEK
SJC4.0VJGAEK
SJC6.0V8GFFK
SJC4.0VJGFEK
SKM1.8VJG1EK

BMW
Chrysler
Chrysler
Chrysler
Chrysler
Diamond Star

Ford
Ford
Ford
Ford

Ford
Ford
Ford
Ford
Ford
Ford
Ford
GM
GM
GM
GMC
Honda
Honda
Honda
Honda
Jaguar
Jaguar
Jaguar
KIA

750cl(V12), 850ci(V12)
Dodge Neon, Plymouth Neon
Dodge Neon, Plymouth Neon
Dodge Neon, Plymouth Neon
Dodge Neon, Plymouth Neon
Eagle Talon, Mitsubishi
Eclipse, Chrysler Sebring,
Dodge Avenger
Windstar
Mustang
T-Bird, Cougar
Grand Marquis, Town Car,
Crown Victoria
Ranger
Windstar
Ranger
Ranger
Ranger
Continental
Ranger
Camaro, Firebird
S10 Pick-Up, Jimmy, Blazer
S10 Pick-Up
Cavalier, Sunfire
Accord LX, EX (V6)
Accord LX, EX (V6)
TL
NSX
AJ16 (SC)
V12
XJS
Sephia

No
No
No

No
No

No
No
No
No

No
No
No
No
No
No
No
Yes
No
No

Yes
Yes
Yes
Yes
Yes
No
No
No
No

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OBDII - On-Board Diagnostic's System - Does My Car Have OBD-II? The Connector and Communications.

STK2.3VJGFEK
STK2.5VJGFEK
STK1.5VJG2EK
STK1.8VJG1EK
SFM2.318G1EK
SFM3.018G1EK
SFM3.028G1FK
SFM4.018G1EK
SFM4.028G1EK
SMB3.6VJGFEK
SMT1.5VJG2EK
SMT1.8VJG2EK

SMT2.4VJG2EK
SNS2.4VJGFFK
SNS2.0VJGFFK
SNS3.0VJG1EK
SNS3.0VJG1FK
SNS2.4VJG2EK
SNS1.6VJG2EK
SNS2.0VJGFEK
SNS3.0VJG1EK
SLR4.0H8GOEK
SFJ2.2VJGFEK
STY3.41JG1GK
STY3.42JG1GK
STY3.0VJGFEK

STY2.42HGJEK
STY2.71HGEEK
STY1.5VHGFEK
STY4.0VJG1GK
STY2.41HG1GK
STY2.71HG1GK
STY3.41JGFEK
STY3.42JGFEK
STY4.55JGFEK
SVV2.3VJGFEK
SVV2.4VJGFEK

Mazda
Mazda
Mazda
Mazda
Mazda*
Mazda*
Mazda*
Mazda*
Mazda*
Mercedes Benz
Mitsubishi
Mitsubishi

Mitsubishi
Nissan
Nissan
Nissan
Nissan
Nissan
Nissan
Nissan
Nissan
Rover
Subaru
Toyota
Toyota
Toyota

Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Volvo (TC)
Volvo

Millenia
Millenia
Protege
Protege
B2300
B3000
B3000
B4000
B4000
S 320, C 280, SL 320
Summit, Mirage
Summit, & Summit Wagon,
Mirage, Expo, LRV
Summit Wagon, Expo, LRV
240 SX
G20
Maxima
Maxima
Altima
Sentra/200 SX
200SX SE-R
Maxima
Range Rover New Model
Legacy
T100 2WD
T100 2WD & 4WD
Camry, Camry Wagon,
ES300, Avalon
Previa, Previa All-trac
T100 2WD
Tercel
LS 400
Tacoma 2WD
Tacoma 4WD
Tacoma 2WD/4WD
Tacoma 4WD
Land Cruiser
850 Turbo Sedan/Wagon
850 Sedan/Wagon

No
No
No
No
No
No
No
No
Yes
No
No

No
Yes
Yes
No
No
Yes
Yes
Yes
No
No
Yes (A/T models only)
Yes
Yes
Yes

No
Yes
No
No
No
No
No
No
No
No
Yes

A note accompanying this list indicated that certification is for the engine group only. The models
listed are believed correct, but the engine is the deciding factor.

E-mail: <

obdii@obdii.com

[ OBD-II Home ]

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The OBD-II Home Page is hosted by

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DTC Lookup Codes - AutoTap

Thank you for visiting our DTC Code LookUp Database!

We would like to email you several additional articles on how things work on your
car, explaining some of the most common failures in today's electronic-controlled
vehicles and what you need to know about them before you spend your own time
or money to fix them. We'll even tell you everything you need to know about that
dreaded Check Engine light.

What fellow DIYer's are saying:

"I find all of your emails useful. If I run into any more problems I
can refer back to all of your emails." -- Jake C.

"The email I received, What Makes the Check Engine Light Tick,
was quite informative and I must say I was pleased to receive it. I
learned a couple of things previously unknown to me and look
forward to the next one." -- P.S. McDaniel.

"Great Information!!! Keep up the good work!!!!" -- Adam G.

"Just wanted to let you know that these emails were very
informative. Thank you for putting it in simple terms." -- Michael D.
Diesel Mechanic.

In order for us to better serve your needs, please complete the survey below. We
will not release your email or mailing address to any other firm for any reason.
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DTC Lookup Codes - AutoTap

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We promise we won't sell or give your email address to anyone, ever.

Address :

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Country:

To help us write articles that are most useful to you we'd like to know a little
about you and your car or truck.

Do you own a 1996 or newer car or light truck?

Yes

Have you had the Check Engine light come on in your vehicle?

Yes

When something goes wrong with my car or truck, I:

Take it to a trusted mechanic

Already know how to do most repairs, so dive right in and fix it

Research how to fix it, online or by asking friends then decide if I
should do it myself or take it to a shop
Swear a few times and keep on driving

Please include me in your repair information email series

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OBD-II Acronyms and Jargon

OBD-II Acronyms and Jargon

Like any government instigated project, OBD-II quickly became a mouse's nest of acronyms,
jargon, shorthand and code phrases that have meaning to the select few and sometimes seem to
serve to keep the rest of us at bay.

Here is a start on untangling these codes. Send in your additions to the list as you run across
them. If you run across acronyms or jargon you don't understand,

send them in

and we'll try to

decipher them for you.

AFC - Air Flow Control

ALDL - Assembly Line Diagnostic Link. Former name for GM (only) Data Link Connector, the
connector socket into which the scan tool plug is inserted; sometimes used to refer to any pre-
OBD II computer signals

CAN - Controller Area Network

CARB - California Air Resources Board

CFI - Central Fuel Injection (a.k.a. Throttle Body Fuel Injection TBI)

CFI - Continuous Fuel Injection

CO - Carbon Monoxide

DLC - Data Link Connector

Driving Cycle - A specific sequence of start-up, warm-up and driving tasks that tests all OBD II
functions

(Details)

DTC - Diagnostic Trouble Code

ECM - Engine Control Module- usually the main in-car computer controlling emissions and engine

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OBD-II Acronyms and Jargon

operation

ECT - Engine Coolant Temperature

EEC - Electronic Engine Control

EEPROM or E

PROM - Electrically Erasable Programmable Read Only Memory

EFI - Electronic Fuel Injection

EGR - Exhaust Gas Recirculation

EMR - Electronic Module Retard

EPA - Environmental Protection Agency. Federal agency. Office of Mobile Sources is the branch
concerned with auto emissions.

ESC - Electronic Spark Control

EST - Electronic Spark Timing

DPFE - Differential Pressure Feedback EGR sensor ( On Ford OBDII systems).

DTC - Diagnostic Trouble Code

FLI - Fuel Level Indicator

Fuel Trim - Engine computer function that keeps the air/fuel mixture as close to the ideal 14.7:1
stoichiometric ratio as possible

HC - Hydrocarbons

HEI - High Energy Ignition

S - Heated Oxygen Sensor

IAT - Intake Air Temperature

ISO 9141 - International Standards Organization OBDII communication mode, used by Chrysler
and most foreign cars. One of three hardware layers defined by OBD II

J1850PWM - (Pulse Width Modulated) SAE-established OBD II communication standard used by

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OBD-II Acronyms and Jargon

Ford domestic cars and light trucks. One of three hardware layers defined by OBD II

J1850VPW - (Variable Pulse Width Modulated) SAE-established OBD II communication standard
used by GM cars and light trucks. One of three hardware layers defined by OBD II

J1962 - SAE-established standard for the connector plug layout used for all OBD II scan tools

J1978 - SAE-established standard for OBD II scan tools

J1979 - SAE-established standard for diagnostic test modes

J2012 - SAE-established standard accepted by EPA as the standard test report language for
emission tests

MAF - Mass Air Flow

MAP - Manifold Absolute Pressure

MAT - Manifold Air Temperature

MFG - Manufacturer

MIL - Malfunction Indicator Light. The "Check Engine Light" on your dash.

NOx - Oxides of Nitrogen

- Oxygen

OBD - On-Board Diagnostics

OBDII or OBD II - Updated On-Board Diagnostics standard effective in cars sold in the US after 1-
1-96

Parameters - Readings on scan tools representing functions measured by OBD II and proprietary
readings

PCM - Powertrain Control Module, the on-board computer that controls engine and drive train

PCV - Positive Crankcase Ventilation

PID - Parameter ID

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OBD-II Acronyms and Jargon

Proprietary Readings - Parameters shown by on-board computers which are not required by
OBD II, but included by manufacturer to assist in trouble-shooting specific vehicles.

PTC - Pending Trouble Code

RPM - Revolutions Per Minute

SAE - Society of Automotive Engineers, professional organization that set the standards that EPA
adopted for OBD and OBD II

Scan Tool - Computer based read-out equipment to display OBD II parameters

SES - Service Engine Soon dash light, now referred to as MIL

SFI - Sequential Fuel Injection

Stoichiometric ( Stoy'-kee-o-metric) Ratio - Theoretical perfect combustion ratio of 1 part gas to
14.7 parts air

TBI - Throttle Body Injection

TPI - Tuned Port Injection

TPS - Throttle Position Sensor

VAC - Vacuum

VCM - Vehicle Control Module, the in-car computer that oversees engine management,
transmission operation, anti-lock brakes, and other functions not directly related to emissions
control

VIN - Vehicle Identification Number

VSS - Vehicle Speed Sensor

WOT - Wide Open Throttle

[ OBD-II Home ]

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OBD-II Acronyms and Jargon

The OBD-II Home Page is hosted by

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General Motors Driving Cycle

General Motors Driving Cycle

A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done
in under fifteen minutes.

To perform an OBDII Driving cycle do the following:

Cold Start. In order to be classified as a cold start the engine coolant temperature must be below
50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key
on prior to the cold start or the heated oxygen sensor diagnostic may not run.

Idle. The engine must be run for two and a half minutes with the air conditioner on and rear
defroster on. The more electrical load you can apply the better. This will test the O2 heater,
Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.

Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr
(55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be
performed.

Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the
O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.

Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to
let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR,
Purge and Fuel Trim diagnostics will be performed.

Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same
diagnostics as in step 3.

Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in
addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed.
If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving
cycles to determine the state of the catalyst.

Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or
brakes or shift gears.

Reprinted on OBDII web site courtesy of General Motors Corporation

© General Motors Corporation

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General Motors Driving Cycle

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Ford Motor Company Driving Cycle

Ford Motor Company Driving Cycle

Description of OBDII Drive Cycle

The following procedure is designed to execute and complete the OBDII monitors and to clear the Ford
P1000, I/M readiness code. To complete a specific monitor for repair verification, follow steps 1 through 4,
then continue with the step described by the appropriate monitor found under the "OBDII Monitor
Exercised" column. When the ambient air temperature is outside 4.4 to 37.8°C (40 to 100° F), or the
altitude is above 2438 meters (8000 feet), the EVAP monitor will not run. If the P1000 code must be
cleared in these conditions, the PCM must detect them once (twice on some applications) before the
EVAP monitor can be "bypassed" and the P1000 cleared. The Evap "bypassing" procedure is described in
the following drive cycle.

The OBDII Drive Cycle will be performed using a scan tool. Consult the instruction manual for each
described function. NOTE: A detailed description of a Powertrain Control Module (PCM) Reset is found in
this section, refer to the table of contents.

Drive Cycle Recommendations:

1. Most OBDII monitors will complete more readily using a "steady foot" driving style during

cruise or acceleration modes. Operating the throttle in a "smooth" fashion will minimize the
time required for monitor completion.

2. Fuel tank level should be between 1/2 and 3/4 fill with 3/4 fill being the most desirable.
3. The Evaporative Monitor can only operate during the first 30 minutes of engine operation.

When executing the procedure for this monitor, stay in part throttle mode and drive in a
smooth fashion to minimize "fuel slosh".

WARNING

STRICT OBSERVANCE OF POSTED SPEED LIMITS AND ATTENTION TO DRIVING CONDITIONS
ARE MANDATORY WHEN PROCEEDING THROUGH THE FOLLOWING DRIVE CYCLES.

For best results, follow each of the following steps as accurately as possible:

OBDII

Monitor

Exercised

Drive Cycle Procedure

Purpose of

Drive Cycle

Procedure

http://www.obdii.com/drivecycleford.html (1 of 4)27-08-2006 22:08:48

Ford Motor Company Driving Cycle

Drive Cycle

Preparation

1. Install scan tool. Turn key on with the
engine off. Cycle key off, then on. Select
appropriate Vehicle & Engine qualifier.
Clear all DTC's/ Perform a PCM Reset.

Bypasses
engine soak
timer. Resets
OBDII Monitor
status.

2. Begin to monitor the following PIDs:
ECT, EVAPDC, FLI (if available) and TP
MODE.

Start vehicle WITHOUT returning to Key
Off.

3. Idle vehicle for 15 seconds. Drive at 64
Km/h (40 MPH) until ECT is at least 76.7°
C (170° F).

Prep for

Monitor

Entry

4. Is IAT within 4.4 to 37.8°C (40 to 100°
F)? If Not, complete the following steps
but, note that step 14 will be required
to "bypass " the Evap monitor and
clear the P1000.

Engine warm-up
and provide IAT
input to the
PCM.

HEGO

5. Cruise at 64 Km/h (40 MPH) for up to 4
minutes.

Executes the
HEGO monitor.

EVAP

6. Cruise at 72 to 104 Km/h (45 to 65
MPH) for 10 minutes (avoid sharp turns
and hills) Note, to initiate the monitor: TP
MODE should =PT, EVAPDC must be
>75%, and FLI must be between 15 and
85%

Executes the
EVAP Monitor
(If IAT is within
4.4 to 37.8° (40
to 100°F))

Catalyst

7. Drive in stop and go traffic conditions.
Include five different constant cruise
speeds, ranging from 40 to 72 Km/h (25
to 45 MPH) over a 10 minute period.

Executes the
Catalyst Monitor.

EGR

8. From a stop, accelerate to 72 Km/h (45
MPH) at 1/2 to 3/4 throttle. Repeat 3
times.

Executes the
EGR Monitor.

http://www.obdii.com/drivecycleford.html (2 of 4)27-08-2006 22:08:48

Ford Motor Company Driving Cycle

SEC AIR/

CCM

(Engine)

9. Bring the vehicle to a stop. Idle with
transmission in drive (neutral for M/T) for
2 minutes.

Executes the
ISC portion of
the CCM.

CCM

(Trans)

10. For M/T, accelerate from 0 to 80 Km/h
(o to 50 MPH), continue to step 11. For A/
T, from a stop and in overdrive,
moderately accelerate to 80 Km/h (50
MPH) and cruise for at least 15 seconds.
Stop vehicle and repeat without overdrive
to 64 Km/h (40 MPH) cruising for at least
30 seconds. While at 64 Km/h (40 MPH) ,
activate overdrive and accelerate to 80
Km/h (50 MPH) and cruise for at least 15
seconds. Stop for at least 20 seconds and
repeat step 10 five times.

Executes the
transmission
portion of the
CCM.

Misfire &
Fuel
Monitors

11. From a stop, accelerate to 104 Km/h
(65 MPH). Decelerate at closed throttle
until 64 Km/h (40 MPH) (no brakes).
Repeat this 3 times.

Allows learning
for the misfire
monitor.

Readiness
Check

12. Access the ON-Board System
Readiness (OBDII monitor status)
function on the scan tool. Determine
whether all non-continuous monitors have
completed. If not, go to step 13.

Determines if
any monitor has
not completed.

Pending
Code
Check and
Evap
Monitor
"Bypass"
Check

13. With the scan tool, check for pending
codes. Conduct normal repair procedures
for any pending code concern. Otherwise,
rerun any incomplete monitor.

Note: if the EVAP monitor is not
complete AND IAT was out of the 4.4 to
37.8° C (40 to 100° F) temperature
range in step #4, or the altitude is over
2438 m. (8000 ft.), the Evap "bypass"
procedure must be followed.

Proceed to step 14.

Determines if a
pending code is
preventing the
clearing of
P1000.

Evap

Monitor

"Bypass"

14. Park vehicle for a minimum of 8
hours. Repeat steps 2 through 12. DO
NOT REPEAT STEP 1.

Allow the
"bypass"
counter to
increment to two.

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Ford Motor Company Driving Cycle

Reprinted on OBDII web site courtesy of Ford Motor Company

© Ford Motor Company

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Whether you need to communicate a few meters or a few miles, convert
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Wireless Modems

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USB Connectivity

USB has moved beyond the desktop. Now used in point-of-sale, medical
and industrial equipment, USB provides a universal solution for device
connectivity. B&B Electronics offers a wide range of USB equipment,
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USB to Serial Converters

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Data acquisition modules from B&B Electronics handle a broad range of
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USB or wireless connections. Compact, low cost modules fit a variety of
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Ethernet Data Acquisition

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Relays, Timers and Voltage Sensor

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Cables and Cable Accessories

B&B Electronics stocks the cables and cabling accessories needed for your
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Research & Development
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Controllers

B&B Electronics new line of controllers will control heating and cooling
levels in every aspect of your system, or intelligently control almost all
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Temperature Controllers

Programmable Logic Relay

Signal Conditioners

Terminal Blocks and Fuse Holders

B&B Electronics selected terminal blocks are modular, secure, insulated,
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Standard Terminal Blocks

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DIN Rail - Snaptrak

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Allied Moulded fiberglass enclosures are fabricated from a proprietary
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fiberglass is particularly suited for wireless applications—no need for an
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Backpanels and Hinged Front Panels

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Ultraline Series

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B&B Electronics now offers Power Supplies and accessories that meet all
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Power Supplies

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Surge Protection

These high performance products are designed to help protect against
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Data Line Surge Protection

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Fuses

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Automotive and Heavy Duty Vehicle Interfaces

B&B Electronics offers solutions for connecting to vehicle communications
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OEM and custom versions are readily available.

AutoTap is a diagnostic package for OBDII vehicles. Popular with home
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is a complete PC based OBDII scantool package.

OEM and Custom Solutions

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OBDII Scan Tool Selection Guide

Shopping Tips for Selecting an OBDII compatible scantool

There are a growing number of scantools compatible with 1996 and newer vehicles with a wide variety of
features. With prices ranging from $250 to $2500 anyone looking for a scantool needs to do a little
homework to find a tool that best fits their needs.

Will it work on your vehicle?

First and foremost, the tool you purchase must support the vehicles you anticipate working on. Although
it's true that OBDII is a standard, there are three different types of hardware communications used by
OBDII vehicles. Some tools support all three and some are manufacturer specific. If you're a diehard
Chevy customer, you may be able to save a few dollars by choosing a manufacturer specific tool.

Supported parameters

Not all scantools are equal. In fact, some aren't even close. As part of the OBDII standard, the US
Environmental Protection Agency mandated that a basic set of emissions related readings be supported
on all OBDII vehicles. The SAE specification J1979 defines these legislated parameters. Many low-end
tools only support these emissions related readings, giving you access to only a dozen or so truly useful
parameters. While these give you some basic vehicle information, they are just a small set of the vehicle
information available through the OBDII port. When shopping for a scantool, be sure to find out if it
supports just the legislated parameters or if it also includes the enhanced (sometimes called proprietary)
diagnostics.

Is it upgradeable?

Each year vehicle manufacturers release new models and revise existing models. For a scantool to fully
support the new vehicles, it must typically be upgraded. Professional quality scantools are upgradeable,
although often at a price of $500 or more per upgrade. Most lower end handheld scantools are not
upgradeable. Check what upgrades will cost before committing to a tool.

Built in help

For anyone working on his or her own vehicle, the Factory Service Manual is a must-have. But the
scantool itself may be able to provide some of that necessary information. When a DTC is set, does the
tool display the DTC number or give the full definition? A tool that displays the full definition will save a lot
of time and frustration. Does the tool offer any information on typical readings to explain what the reading
is? A simple sentence or two of explanation can save a lot of trips back and forth to the shop manual.

http://www.obdii.com/scantool_selection.html (1 of 2)27-08-2006 22:09:50

OBDII Scan Tool Selection Guide

Data logging or storage

A sure way to park your car in a ditch is to try and watch a scantool display while doing a roadtest. A tool
that stores data to allow safe viewing back at the garage is a must. Be certain that the tool you buy has
this capability.

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OBD-II Links

OBD-II Links

About OBDII

OBD III

Automotive Trade Associations

OBDII Resources and Training

Environmental Protection Agency

Pre-OBDII diagnostic information

California Air Resources Board (CARB)

SAE Reference Publication Sources

About OBD-II

UNDERSTANDING OBDII: PAST, PRESENT & FUTURE

- article by Larry Carley. A

comprehensive overview of On-Board Diagnostics' past and present, with a big brother-ish view of
its possible future.

Larry Carley's Home Page

- A skilled automotive repair professional, who also writes superbly,

logs his articles on repair topics and offers a variety of auto related software. Some OBD II related,
some just neat.

OnBoard Diagnostics Article

- OBDII and performance modifications from the pages of High Tech

Performance magazine.

[ Back to Top ]

OBD III

Automotive Service Assn. Article

- on the remote surveillance aspects of OBD III.

[ Back to Top ]

Environmental Protection Agency

http://www.obdii.com/links.html (1 of 4)27-08-2006 22:10:02

OBD-II Links

Downloadable files of EPA final OBD-II directives.

- 6-94 through 5-97

EPA Statement of 7/24/96 regarding decision to approve CARB request for OBD II waiver.

EPA's Position Paper on the effects of On Board Diagnostics (OBD II).

- March 14, 1997. Now that

the final rules for these systems are in place, EPA proposes that MOBILE6 attempt to account for
the benefits of OBD for the newer model years.

EPA Links Page to OBD-II documents.

- May, '96 to Nov., '97

EPA OBD Links Page.

- Primarily to other EPA publications.

Federal Register Notices by Publication Date with Web Links.

- EPA Office of Transportation and

Air Quality (OTAQ). There is no guarantee that this is a complete list, but it should be virtually
everything generated by OTAQ since 1994.

Continuation of EPA above link list.

- through 2-19-98

[ Back to Top ]

California Air Resources Board (CARB)

California Air Resources Board homepage.

California regulations for OBDII

- This has the 1968.1 California regulations for OBDII, a hot topic

at the SAE seminar (This is similar to the CFR that the EPA has).

[ Back to Top ]

Automotive Trade Associations

COMBATING OBD-II...AGAIN. A position paper from SEMA.

- The Environmental Protection

Agency recently announced plans to impose stricter emission standards for ozone-related
emissions and airborne particulates. The tougher standards would force states and municipalities
to achieve further emission and particulate reductions from sources that include factories,
refineries and automobiles.

[ Back to Top ]

SAE Reference Publication Sources

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OBD-II Links

SAE On-Board Diagnostics

- for Light and Medium Duty Vehicles Standards Manual

Diagnostic systems--Part 2: digital information

- This part of ISO 9141 describes a subset of ISO

9141:1989. It specifies the requirements for setting up the interchange of digital information
between on-board emission-related Electronic Control Units (ECUs) of road vehicles and the SAE
OBD II scan tool as specified in SAE J1978.

OBD II Scan Tool

- This SAE Recommended Practice defines the requirements of OBD II scan

tools, i.e. test equipment that will interface with vehicle modules in support of the OBD II diagnostic
requirements.

Expanded Diagnostic Protocol for OBD II Scan Tools

- This SAE Recommended Practice defines

the Expanded Diagnostic Protocol (EDP), the requirements for the SAE J1978 OBD II Scan Tool
for supporting the EDP protocol, and associated requirements for diagnosis and service
information to be provided by motor vehicle manufacturers.

Universal Interface for OBD II Scan

- SAE J1978 defines the requirements of the OBD II scan

tool.

[ Back to Top ]

Pre-OBDII diagnostic information

Retrieve codes from Pre-OBDII Vehicles:

Ford

[ Back to Top ]

OBDII Resources and Training

Helm, Inc. Online Bookstore

- Source for factory service manuals and other repair data for GM and Ford

vehicles and some import models.

Autoshop101 - Automotive Training Resource Site

- Automotive training support for Automotive

technicians, students, and teachers. Online ASE style electrical practice tests, technical articles, online
tutorials, etc.

Bergwell

- Thorough OBDII information available in books and video, on CD ROM and on line. All courses

written by technicians for technicians!

[ Back to Top ]

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OBD-II Links

[ OBD-II Home ]

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B&B Electronics

, Ottawa, Illinois

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OBDII Technical Library - OBDII

OBDII Technical Library

We're pleased to bring you this growing collection of articles to explain all things OBDII for the
DIYer, performance enthusiast and professional technician.

Diagnosing an Engine Misfire

Diagnosing Light-Duty Diesels

Diagnosing Misfires

Diagnostic Flow Charts…Do They Always Work?

Distributorless Ignition Systems (DIS)

Introduction to Emissions Systems

Introduction to Engine Management Systems

OBDII and Emissions Testing

OBDII: Past, Present and Future

Onboard Diagnostics Demystified

PDA-Based Diagnostics: Taking Shops by Storm?

Preventive Maintenance: Fluids and Filters