Self-Diagnosis
Self-diagnosis: the board computer checks itself and a part of its periphery and stores faults in the program
memory that last longer than approx. S seconds.
After faults are stored, an "F" (fault flag) appears in the upper left corner of the lime display. In addition,
the board computer functions affected by the faults are blocked by a flashing "F" in the function display.
If the fault is no longer present after an interval of approx. 8 seconds, the fault flag is erased and the
affected board computer functions are released again.: The trouble code remains stored in the program I
memory, however. The display of a trouble code without an active fault I flag indicates the presence of a loose
contact.
The stored trouble codes can be read out by means of TECH 1 or Diagnostic Switch KM-640 (see section
5.4.1 or section 5.6.4).
Range Calibration
Fit paperclip to Diagnostic plug A-D
Fit 120 Ohm resistor in place of tank sensor.
Remove Plug arrowed right, and connect resistor to plug.
Adjust diagnostic mode 5 by repeatedly actuating the stepping
key.
The clock display shows d: 5
The function display remains blank.
Change is made to the actual calibration mode by pressing the
minutes hole contact.
The clock display shows "A".
The function selection display flashes the range arrow.
The function display shows "12L" (calibration with defined petrol
quantity). This calibration mode is used only in the factory.
A switchover is made to the calibration mode with substitutional
resistance by pressing the stepping key.
The function display shows the value of substitutional resistance.
The calibration process is initiated after the start key
is actuated> 3 sec; the function display shows "----" until storage
is ended.
After approx. 5 sec, the function display shows the range
corresponding to the substitutional resistance (approx. 120 km or
75 m).
[83 miles on my V6]
The calibration mode is exited by disconnecting the diagnostic
switch.
If during calibration the board computer recognises a faulty
signal level, an "H" (voltage too high) or "L" (voltage too low)
flashes for 5 sec instead of the range being displayed. The board
computer then returns to diagnostic mode 5.
In this case, resistor is fitted.
After a successful recalibration, the following measures are to be
carried out:
- Remove resistor, connect tank gauge (ignition OFF!)
Erase trouble code memory (see section 6.3.2)
- Select board computer range function and press start key. The
function display shows the range calculated from the current tank
content.
Range Correction
Fit paperclip to Diagnostic plug A-D
Adjust diagnostic mode 5 by repeatedly pressing the stepping key.
The Clock display shows d : 5
The function display remains blank
Change is made to the actual correction mode by pressing the hours hole
contact.
The clock display shows A : xx; at the same time, the currently stored
correction appears at the positions designated by xx. The correction value is
displayed without a decimal point, e.g. 6 for 0.6 gallon
The function display flashes the range arrow.
Press the Stepping key.
The function display shows the range based on the current tank content, a
standard consumption of 28.3 mpg and the currently adjusted correction.
The stepping key can be used to adjust the desired correction in the clock
display in the continuous mode. Simultaneously, the displayed range
changes by approximately 3 miles with each key press.
If the right correction value has been set, the correction value is
permanently stored in the program memory by actuating the start key > 1
second; the function display shows ---- until storage is complete.
The correction mode is exited by disconnecting he diagnostic switch.
Now select board computer range function and press the start key. The
function display shows the range calculated from the current tank content.
Diagnostic Mode d:1
Fit paperclip to Diagnostic plug A-D
The clock display shows designation "d:1".
The function display introduces the trouble code
read-out by flashing the number "12" three times
and then flashing the trouble codes three times in
numerical order.
The entire trouble code set is repeatedly given until diagnostic mode 1 is
exited.
If no fault is present,"- - - -" is flashed instead of the trouble code.
After removal of cause of fault, the fault memory can be erased by actuating
the start key.
Trouble
Trouble Code Explanation Trouble-shooting
Code
- Tank indicator in instrument does not function:
1. Fuel gauge or connection defective (short circuit
to ground)
2. Instrument defective
The trouble code is set when the
the fuel gauge signal voltage at
-Tank indicator in instrument functions:
167 the board computer is too small.
1. Lead interruption between fuel gauge and board
Simultaneously, the range function
computer Ter. 26,
is blocked by a flashing "F".
bimetal measuring device or Ter. 8, on
VECTRA/CAVALIER with LCD instrument
2. Wrong program memory installed
3. Board computer defective
- Tank indicator in instrument does not function:
1. Fuel gauge or connection defective (interruption)
The trouble code is set when the
2. Ground connection at fuel gauge defective
the fuel gauge signal voltage at
3. Instrument defective
168 the board computer is too large.
Simultaneously, the range function
- Tank indicator in instrument functions:
is blocked by a flashing "F".
1. Wrong program memory installed
2. Board computer defective
1. Disconnect temperature sensor plug connection
P13 and measure
The trouble code is set when the
resistance of temperature sensor (multimeter,
temperature sensor signal voltage at
measuring range: 2
the board computer is too low.
169
Nominal value: 700 - 135 k .
Simultaneously, the outside
2. Short circuit to ground of lead between board
temperature function is blocked by a
computer Ter. 13 and
flashing "F".
temperature sensor plug P13
3. Board computer defective
1 .Disconnect temperature sensor plug connection
P13 and measure
The trouble code is set when the resistance of temperature sensor (multimeter,
temperature sensor signal voltage at measuring range: 2
the board computer is too high.
Nominal value: 700 - 135 k .
171
Simultaneously, the outside
2.Lead interruption between board computer Ter. 13
temperature function is blocked by a
and temperature sensor plug P13
flashing "F".
3.Lead interruption between board computer Ter. 12
and temperature sensor plug P13
4.Board computer defective
The trouble code is set when the
injection control unit signal shows
1. Short circuit to ground of lead between board
a ground level longer than 500 ms;
computer Ter. 24 and
The following functions are blocked
173 control unit of injection system
by a flashing "F".
2.Board computer defective
- current consumption
3.Control unit of injection system defective
- average consumption
- range
01-43 pulses
01-47 tyres
122-141 pulses
122-141 tyres
30-80 tyres
30-81 pulses
46-59 pulses
48-61 tyres
60-75 pulses
62-75 tyres
81-83 tyres
86-103 pulses
96-121 pulses
96-121 tyres