CARBURETED ENGINE

MANAGEMENT SYSTEM

(CEMS)

H3.50-5.50XM (H70-120XM) [K005, L005]

PART NO. 1466175

2200 SRM 744

SAFETY PRECAUTIONS

MAINTENANCE AND REPAIR

• When lifting parts or assemblies, make sure all slings, chains, or cables are correctly

fastened, and that the load being lifted is balanced. Make sure the crane, cables, and
chains have the capacity to support the weight of the load.

• Do not lift heavy parts by hand, use a lifting mechanism.

• Wear safety glasses.

• DISCONNECT THE BATTERY CONNECTOR before doing any maintenance or repair

on electric lift trucks.

• Disconnect the battery ground cable on internal combustion lift trucks.

• Always use correct blocks to prevent the unit from rolling or falling. See HOW TO PUT

THE LIFT TRUCK ON BLOCKS in the Operating Manual or the Periodic Mainte-
nance section.

• Keep the unit clean and the working area clean and orderly.

• Use the correct tools for the job.

• Keep the tools clean and in good condition.

• Always use HYSTER APPROVED parts when making repairs. Replacement parts

must meet or exceed the specifications of the original equipment manufacturer.

• Make sure all nuts, bolts, snap rings, and other fastening devices are removed before

using force to remove parts.

• Always fasten a DO NOT OPERATE tag to the controls of the unit when making repairs,

or if the unit needs repairs.

• Be sure to follow the WARNING and CAUTION notes in the instructions.

• Gasoline, Liquid Petroleum Gas (LPG), Compressed Natural Gas (CNG), and Diesel fuel

are flammable. Be sure to follow the necessary safety precautions when handling these
fuels and when working on these fuel systems.

• Batteries generate flammable gas when they are being charged. Keep fire and sparks

away from the area. Make sure the area is well ventilated.

NOTE:

The following symbols and words indicate safety information in this

manual:

WARNING

Indicates a condition that can cause immediate death or injury!

CAUTION

Indicates a condition that can cause property damage!

Carbureted Engine Management System (CEMS)

Table of Contents

TABLE OF CONTENTS

Description .........................................................................................................................................................

Ignition Control System ....................................................................................................................................

Setting Timing Reference..............................................................................................................................

Idle Speed Control System ............................................................................................................................

Curb Idle Setting Procedure .........................................................................................................................

Governor Control System ..................................................................................................................................

Closed-Loop Fuel System ..................................................................................................................................

Closed-Loop Fuel Control ..............................................................................................................................

Entering Closed-Loop Control ......................................................................................................................

Normal Closed-Loop Operation ....................................................................................................................

Closed-Loop Diagnostics................................................................................................................................

O.E. Tune Valve Action at Engine Shutdown ..............................................................................................

Diagnostic System..............................................................................................................................................

Closed-Loop Diagnostic Troubleshooting .....................................................................................................

Diagnostic Troubleshooting...........................................................................................................................

This section is for the following models:

H3.50-5.50XM (H70-120XM) [K005, L005]

"THE

QUALITY

KEEPERS"

HYSTER

APPROVED

PARTS

2200 SRM 744

Description

The CEMS (Carbureted Engine Management Sys-
tem) provides digital electronic control of the engine
ignition, idle speed, and governed speed. See Fig-
ure 1. The system is also capable of controlling op-
tional high- and low-pressure fuel shutoff devices.

Control of the above functions is managed by the
ECU (Electronic Control Unit). The ECU constantly
monitors engine speed, coolant temperature, MAP
(manifold absolute pressure), and battery voltage.

Using these inputs, the CEMS maintains proper
ignition, idle, and governor control.

The CEMS also includes a complete diagnostic sys-
tem. This feature constantly monitors the status of
critical input and output signals, and will warn the
operator in the event of a failure. The diagnostic sys-
tem will also provide information to assist in locating
and correcting the failure.

Figure 1. CEMS (Carbureted Engine Management System)

Ignition Control System

2200 SRM 744

Ignition Control System

The CEMS ECU controls the EST (engine spark tim-
ing) above 1000 rpm based on a factory-programmed
ignition table. Spark timing is controlled by the GM
ignition module below 1000 rpm.

SETTING TIMING REFERENCE

For the ECU to provide accurate ignition timing, the
reference or base ignition timing must be accurately
set at TDC (0 BTDC).

The purpose of this procedure is to establish a TDC
timing reference for the ECU. When the distributor
has been moved, or on initial system installation, it
is necessary to perform this procedure as follows.

With ignition key turned to OFF position, re-
move protective cover and install shorting plug
on COMM connector located next to the ECU. See
Figure 2.

ECU (ELECTRONIC CONTROL UNIT)

COMM CONNECTOR

Figure 2. COMM Connector

Turn ignition key to ON position. The Check En-
gine dash light should be ON.

Start engine.

Using a timing light, set timing to TDC (0
BTDC).

Turn ignition key to OFF position.

Remove shorting plug from COMM connector
and replace with protective cover.

Start engine.

In the above steps, note that when the key is first
turned ON, any stored diagnostic codes (see Diagnos-
tic System) will begin flashing via the Check Engine
dash light. Once the engine is started, the Check En-
gine light will remain in a continuous ON condition
while the engine is running.

At the conclusion of the above procedure, the ignition
timing will be that which is acquired from the Igni-
tion Map Table.

IDLE SPEED CONTROL SYSTEM

Engine idle speed is managed by the ECU. The ECU
controls the Idle Speed Control Valve (see Figure 3),
which regulates the amount of air that bypasses the
throttle plates. The engine idle speed of 725 rpm is
programmed into the ECU at the factory. The ECU
maintains the factory-programmed engine speed via
opening and closing the Idle Speed Control Valve,
based on current engine operating conditions such as
engine temperature and load. Curb idle must be set
100 rpm below that of the factory-programmed en-
gine idle speed.

ISC ELECTRICAL CONNECTOR

ISC (IDLE SPEED CONTROL VALVE)

Figure 3. Idle Speed Control Valve

2200 SRM 744

Governor Control System

CURB IDLE SETTING PROCEDURE

Engine should be warm, at normal operating
temperature.

Disconnect electrical connector from the ISC
(Idle Speed Control). This will trigger the check
engine light - disregard. See Figure 3.

Adjust idle screw so that engine is running at 625
rpm (100 rpm below the programmed Idle Set
Point of 725 rpm). See Figure 4.

Reconnect the ISC electrical connector.

Reset Check Engine Light by removing main
power supply fuse, or disconnect negative bat-
tery cable for a minimum of 5 minutes. Verify
that no diagnostics codes (other than the 10 flash
ECU "OK" code) appear. If diagnostic codes are
present, repeat removing main power supply

fuse for a minimum of 5 minutes. See Diagnostic
System for detailed procedure.

CURB IDLE ADJUSTMENT SCREW

Figure 4. Curb Idle Adjustment Screw

Governor Control System

The Governor Control System utilizes an electronic
governor motor connected to the throttle shaft. The
accelerator pedal is not connected directly to the
throttle shaft.

The pedal connects to the throttle

shaft via a lost motion linkage system.

This lost

motion system allows driver demand to control ac-
celeration and engine speed, but allows the governor
motor to override driver demand in the event of
any engine overspeed condition.

The factory-pro-

grammed governed engine speed is 2200 rpm.

The Governor Motor (Figure 5) is an electronic ac-
tuator, which is controlled by the ECU. Engine gov-
ernor speeds are programmed at the factory for the
optimum combination of performance, safety, and en-
gine life. The Governor Motor must be connected
for proper engine operation. In the event the Gov-
ernor Motor system fails or is intentionally discon-
nected or bypassed, the Diagnostic System will trig-
ger the check engine light. If the engine speed ex-
ceeds factory-authorized limits (2975 rpm), factory-
programmed high rpm limit will cause the fuel to the
engine to be immediately shut off by the ECU, via
closing the Low-Pressure (or optional High-Pressure)

fuel lock-off. As soon as engine speed is reduced to
the factory-programmed level of 1800 rpm, the LPG
fuel lock-off will be reopened. This will result in a
noticeably harsh engine speed oscillation if attempts
to operate the engine in the overspeed condition per-
sist.

GOVERNOR MOTOR

Figure 5. Governor Motor

Closed-Loop Fuel System

2200 SRM 744

Closed-Loop Fuel System

CLOSED-LOOP FUEL CONTROL

The main purpose of closed-loop control is to main-
tain the air/fuel mixture within a very narrow region
to minimize exhaust emissions. The two primary de-
vices used in closed-loop control are the O.E. tune
valve and the O

sensor. The closed-loop strategy

is similar to that used in closed-loop gasoline Fuel
Injection systems. An O

sensor is constantly mon-

itored by the ECU (Electronic Control Unit) to de-
tect a lean or rich condition. If a lean condition is de-
tected, the O.E. tune valve is moved to a more open
position to allow more fuel to mix with the intake
air (enrichment). If a rich condition is detected, the
valve is moved toward a more closed position to de-
crease the amount of fuel added to the intake air (en-
leanment).

ENTERING CLOSED-LOOP CONTROL

When the engine is first started, there is a required
wait period before the ECU will permit closed-loop
operation to begin. The purpose of this wait period is
to permit the O

sensor to reach its operating temper-

ature. In a warm engine, this wait period may be one
minute or more. The engine operates in "open-loop"
while it waits for the O

sensor to reach its operating

temperature. In this mode, the O

sensor does not

toggle. During idle warm-up, the valve will "park" at
a fixed location.

NORMAL CLOSED-LOOP OPERATION

When the O

sensor has reached its operating tem-

perature, the ECU will enter closed-loop fuel control.
In this mode, the O

sensor should constantly toggle

between RICH and LEAN states. At idle, the toggle
rate may be as slow as 1 toggle per second. At higher
RPM/load conditions, the toggle rate may exceed 20
toggles per second. If toggling should stop, the ECU
will enter the open-loop mode in which the valve po-
sition for a given RPM and engine load is acquired
from an internal table. Although the O

sensor has

a built-in heater to help maintain operation within

the required temperature range, extremely cold am-
bient temperatures may cause the O

sensor to stop

toggling at idle RPM.

Other conditions which may cause loss of toggling
are a faulty or damaged mixer or vaporizer/regula-
tor, which supplies insufficient fuel to allow the mix-
ture to go RICH or such an excessive fuel supply that
the valve must nearly close to limit fuel flow. For
the overly LEAN condition, the valve will continue to
move in an "open" direction until it reaches the max-
imum open position; it will then instantly "park" at
a position determined by the internal table.

For the condition in which the valve is unable to
cause a LEAN state, the valve will move in a clos-
ing direction until it is almost completely closed and
then park at that position. In either case, a subse-
quent toggle of the O

sensor or a transient RPM/load

condition will cause the ECU to begin a new attempt
to enter the toggling closed-loop mode.

CLOSED-LOOP DIAGNOSTICS

See the Diagnostic System section in this manual for
diagnostic procedures in a closed-loop system.

O.E. TUNE VALVE ACTION AT ENGINE
SHUTDOWN

CAUTION

The engine should NEVER be operated with
the O.E. tune valve disconnected or when the
O.E. tune valve is in a fail condition. The valve
failure MUST be corrected.

During engine stall or normal engine (KEY OFF)
shutdown, the O.E. tune valve moves to the fully
closed position and remains in that position for a
minimum of 30 seconds to inhibit fuel flow through
the valve. The valve requires battery power during
this transient closure period; therefore, the battery
should not be disconnected for at least 3 minutes af-
ter shutdown.

2200 SRM 744

Diagnostic System

When certain failures are detected by the ECU soft-
ware, a flash code for the failure is stored in memory
and the Check Engine light is turned on. See Table 1.
Each failure has a unique flash code. Each flash code
begins with at least one long flash followed by at least

one short flash. A long flash is about 1 second in du-
ration. A short flash is about 1/2 second in duration.
There is approximately a 2-second interval between
flash codes.

Table 1. Diagnostic Codes

Device

Open

Shorted

General Failure

ECU Processor

N/A

10 Short

Battery

N/A

1 long, 1 short

N/A

MAP Sensor

1 long, 3 short

1 long, 4 short

N/A

Water Temp sensor

1 long, 5 short

1 long, 6 short

N/A

Air Temp (EFI)

1 long, 7 short

1 long, 8 short

N/A

Governor Actuator

2 long, 1 short

2 long, 2 short

N/A

IAC Actuator

2 long, 3 short

2 long, 4 short

N/A

Low-Pressure Fuel Lock-Off Valve

3 long, 1 short

3 long, 2 short

N/A

High-Pressure Fuel Lock-Off Valve

3 long, 3 short

3 long, 4 short

N/A

Lock-off Valve (LPG Controller - Dana
EPIC/Teleflex-GFI)

3 long, 3 short

3 long, 4 short

N/A

Sensor (Closed-Loop)

N/A

1 long, 2 short

N/A

O.E. Tune Valve (Closed-Loop)

3 long, 1 short

3 long, 2 short

N/A

The flash codes are displayed by flashing the specific
failure code(s) through the Check Engine light by fol-
lowing these steps.

Key in OFF position, insert shorting plug into
COMM connector. See Figure 2.

Key in ON position, DO NOT START ENGINE.

ECU "OK" code of 10 short flashes should begin
flashing.

Flash codes for specific failures begin flashing.
If no failures are present, ECU "OK" code of 10
short flashes will continue flashing.

After last code is displayed, cycle repeats with
ECU "OK" code.

Codes are cleared from ECU memory when ECU
power is disconnected for a minimum of 5 min-
utes. This is accomplished by removal of main
power fuse or battery disconnect for a minimum
of 5 minutes.

CAUTION

Running engine with shorting plug installed
will cause timing to operate at TDC. See Set-
ting Timing Reference.

Remove shorting plug when finished.

In addition to storing and subsequently displaying
the flash codes, certain failures, upon detection, will
cause the ECU to take additional action. If a short
condition is detected on an actuator or valve device,
the ECU will turn device to the OFF position to elim-
inate a potential high-current condition. The device
will remain disabled until the short is removed via
the above diagnostics procedure. If the device is de-
tected as OPEN, the ECU will continue to attempt to
operate the actuator.

If a MAP sensor failure is detected, a default condi-
tion of idle manifold pressure will be used.

Diagnostic System

2200 SRM 744

CLOSED-LOOP DIAGNOSTIC
TROUBLESHOOTING

The O.E. tune valve and the O

sensor are constantly

monitored for normal operation. The valve is tested
for OPEN and SHORTED conditions. All of the fol-
lowing conditions must be true to cause an O

sensor

failure:
• O.E. tune valve must be installed
• Engine coolant temperature sensor must be oper-

ating normally

• Engine coolant temperature must be greater than

49 C (120 F)

• Engine MAP sensor must be operating normally
• MAP must be 132 to 328 mm Hg (5.2 to 12.9 inHg)
• Engine must be running
• O

sensor must not have toggled for 30 seconds

• O.E. tune valve must be in AUTO (not MANual)

mode

• Engine must have been running for at least 10 min-

utes

• Engine RPM must be within 100 RPM of Governor

Setpoint

Failure of the O

sensor will cause the ECU enter the

open-loop fuel control mode. Valve positions are then
acquired from the internal table.

A FAIL SHORT or FAIL OPEN O.E. tune valve will
most likely cause the valve to be fully opened, result-
ing in a very RICH mixture. The Check Engine Light
will come on if any of the above conditions occur. See
Table 1.

DIAGNOSTIC TROUBLESHOOTING

Troubleshooting for electrical shorts or open circuits
should be conducted with a quality DVOM (Digital
Volt Ohmmeter). An infinite or OL (open load) read-
ing on the Ohm display will indicate open conditions.
Check for short conditions between other nearby pins
and ground of the suspected circuit. Shorts will be
indicated with a low Ohm reading (low resistance)
between the shorted circuits.

After the open, short, or failed component has been
identified and corrected or replaced, disconnect bat-
tery power for a minimum of 5 minutes to clear stored
diagnostic codes. Start system and verify no check
engine light appears.

Refer to Table 2 for troubleshooting procedures for
the Carbureted Engine Management System.

Table 2. Diagnostic Troubleshooting

Diagnostic Code (flash count)

Possible Cause

Corrective Action

Ten short
Ten flash is the ECU "OK" code

No Fault – ECU OK

None Required

One long, one short
(Low battery voltage)
Check engine light is set if battery
voltage goes below 9.8 V, 1 minute
after engine start.

Battery voltage goes below 9.8 V
1 minute after engine start.

Check charging system.
Check battery.

One long, five short (Coolant
sensor - open)

Failed coolant sensor

Check coolant sensor. Verify
resistance across two sensor
terminals is 2.5K

(±500 ) @

39.2 C (102.5 F).

Replace if out of spec.

Coolant sensor is a two-way
variable thermistor. As the sensor
temperature increases, resistance
decreases.

Faulty wiring (open)

Remove ECU connector. Check
sensor connector and wiring for
open circuits in coolant sensor
wiring between:
• ECU Pin J1 and Sensor Connector

Pin A, #428

• ECU Pin H1 and Sensor Connector

Pin B, #642

2200 SRM 744

Diagnostic System

Table 2. Diagnostic Troubleshooting (Continued)

Diagnostic Code (flash count)

Possible Cause

Corrective Action

One long, six short
(Coolant sensor - short)

Failed coolant sensor

Check coolant sensor. Verify
resistance across two sensor
terminals is 2.5K

(±500 ) @

39.2 C (102.5 F).

Replace if out of spec.

Coolant sensor is a two-way
variable thermistor. As the sensor
temperature increases, resistance
decreases.

Faulty wiring (short)

Remove ECU connector. Check
sensor connector and wiring circuits
listed below for shorts to ground
and between 2 sensors wires.
• Sensor Connector Pin A, #428
• Sensor Connector Pin B, #642

Faulty wiring (open)

Remove ECU connector. Check
sensor connector and wiring for
open circuits in MAP sensor wiring
between:
• ECU Pin E3 and Sensor Connector

Pin C, #425/425A

• ECU Pin D3 and Sensor Connector

Pin A, #637/637A

• ECU Pin F3 and Sensor Connector

Pin B, #427

One long, three short
(Map sensor - open)
MAP (Manifold Absolute Pressure)
Sensor output varies between 0
and 5 VDC as engine vacuum
changes, based on throttle opening
and engine load.

Failed MAP sensor

Replace MAP sensor.

Faulty wiring (short)

Remove ECU connector. Check
sensor connector and wiring circuits
listed below for shorts to ground
and between 3 sensor wires.
• Sensor Connector Pin C, #425A
• Sensor Connector Pin A, #637A
• Sensor Connector Pin B, #427

One long, four short
(MAP sensor - short)
MAP (Manifold Absolute Pressure)
Sensor output varies between 0
and 5 VDC as engine vacuum
changes based on throttle opening
and engine load.

Failed MAP sensor

Replace MAP sensor

Faulty wiring (open)

Remove ECU connector. Check
Governor connector and wiring for
open circuits in Governor Actuator
wiring between:
• ECU Pin C2 Governor and Actua-

tor Connector Pin A, #440A

• 12 V system power 10 amp fuse

and Governor Actuator Connector
Pin B, #103/103D

Two long, one short
(Governor Actuator - open)
The Governor Actuator is
electronically controlled by the
ECU via a PWM (Pulse Width
Modulated) output. Governed
engine speeds and related control
parameters are preset at the
factory.

Failed Governor Actuator

Disconnect Governor Actuator
connector. Verify resistance
between two leads on Governor
Actuator is 1.8

to 2.1

@ 20 C

(68 F).

Replace if out of spec.

Diagnostic System

2200 SRM 744

Table 2. Diagnostic Troubleshooting (Continued)

Diagnostic Code (flash count)

Possible Cause

Corrective Action

Faulty wiring (short)

Remove ECU connector. Check
Governor connector and wiring
circuits listed below for shorts to
ground and between 2 Governor
wires.
• Governor Actuator Connector Pin

A, #440A

• 12 V system power 10 amp fuse

(Governor Actuator Connector Pin
B), #103D

Two long, two short
(Governor Actuator - short)
The Governor Actuator is
electronically controlled by the
ECU via a PWM (Pulse Width
Modulated) output. Governed
engine speeds and related control
parameters are preset at the
factory.

Failed Governor Actuator

Disconnect Governor Actuator
Connector leads. Verify resistance
between two leads on Governor
Actuator is 1.8

to 2.1

@ 20 C

(68 F).

Replace if out of spec.

Faulty wiring (open)
1.

ISC Connector

Lock Side

Opposite of Lock Side

Remove ECU connector. Refer
to diagram at left and check ISC
connector and wiring for open
circuits in Idle Speed Control wiring
between:
• 12 V system power ignition 10 amp

fuse and terminal on Lock Side of
ISC Connector Pin A, #103/103E

• ECU pin F2 and terminal opposite

of Lock Side of ISC Connector Pin
B, #439

Two long, three short
(Idle Speed Control - open)
The Idle Speed Control is
electronically controlled by the
ECU via a PWM (Pulse Width
Modulated) output. Engine
idle speed and related control
parameters are preset at the
factory.

Failed Idle Speed Control

Disconnect ISC connector. Verify
resistance across ISC terminals is
9.8

(±2.0 ).

Replace if out of spec.

2200 SRM 744

Diagnostic System

Table 2. Diagnostic Troubleshooting (Continued)

Diagnostic Code (flash count)

Possible Cause

Corrective Action

Faulty wiring (short)
1.

ISC Connector

Lock Side

Opposite of Lock Side

Remove ECU connector. Refer to
diagram at left, and check ISC
connector and wiring circuits listed
below for shorts to ground and
between ISC leads.
• 12 V system power ignition 10 amp

fuse (Lock Side of ISC Connector),
Pin A, #103E

• ECU Pin F2 (opposite of Lock Side

of ISC Connector), Pin B, #439

Two long, four short
(Idle Speed Control - short)
The Idle Speed Control is
electronically controlled by the
ECU via a PWM (Pulse Width
Modulated) output. Engine
idle speed and related control
parameters are preset at the
factory.

Failed Idle Speed Control

Disconnect ISC connector. Verify
resistance across ISC terminals is
9.8

(±2.0 ).

Replace if out of spec.

Faulty wiring (open)

Remove ECU connector. Check
Low-Pressure Valve connectors and
wiring for open circuits in wiring
between:
• 12

power

source,

(battery

amp

fuse)

and

Low-Pres-

sure Valves Connection Pin B,
#301C/301K.

• ECU

and

Low-Pres-

sure Valves Connection Pin A,
#438B/438C.

Three long, one short
(Low-Pressure Fuel Lock-off -
open)

Failed Low-Pressure Fuel Lock-off
Valves

Check Low-Pressure Fuel Lock-off
Valves. Verify resistance is
21.8-25.0

@ 20 C (69.8 F).

Replace if faulty.

Diagnostic System

2200 SRM 744

Table 2. Diagnostic Troubleshooting (Continued)

Diagnostic Code (flash count)

Possible Cause

Corrective Action

Faulty wiring (short)

Remove ECU connector. Check
Low-Pressure Valve connectors
and wiring circuits listed below
for shorts to ground and between
Low-Pressure Valve leads.
• 12 V power source, (battery 10

amp fuse) to Low-Pressure Valves
Connection Pin B, #301C/301K.

• ECU

Low-Pres-

sure Valves Connection Pin A,
#438B/438C.

Three long, two short
(Low-Pressure Fuel Lock-off -
short)

Failed Low-Pressure Fuel Lock-off
Valves

Check Low-Pressure Fuel Lock-off
Valves. Verify resistance is
21.8-25.0

@ 20 C (69.8 F).

Replace if faulty.

Faulty wiring (OPEN)

Remove ECU connector. Check
Lock-off connector and wiring
circuits listed below for open circuits
in wiring between:

• 12 V power source, ECU pin B3 to

Series 1 Converter pin A, #857.

Note that 12 V is supplied when
engine is cranking or running, but
not when key is just switched to ON
position. Quick pulse from ECU
checks coil condition when key is
switched on.
• Ground, Series 1 Converter pin

B to harness ground at cylinder
head, #704 and #647.

Three long, three short
(OPEN) LPG Controller (Dana
EPIC/Teleflex-GFI)

Failed Series 1 Converter Lock-off,
Coil is OPEN.

Check Series 1 Converter. Verify
resistance is between 7.3

to 7.9

20 C (68 F).

Replace if faulty.

2200 SRM 744

Diagnostic System

Table 2. Diagnostic Troubleshooting (Continued)

Diagnostic Code (flash count)

Possible Cause

Corrective Action

Faulty wiring (SHORT)

Remove ECU Connector. Check
Lock-off connector and wiring
circuits listed below for shorts
to ground and between Series 1
Converter leads.
• 12 V power source, ECU pin B3 to

Series 1 Converter pin A, #857.

B to harness ground at cylinder
head, #704 and #647.

Three long, four short (SHORTED)
LPG Controller
(Dana EPIC/Teleflex-GFI)

Failed Series 1 Converter Lock-off,
Coil is SHORTED.

Check Series 1 Converter. Verify
resistance is between 7.3

to 7.9

20 C (68 F).

Replace if faulty.