Fuel Gauge

Checking fuel gauge

Preceding operation:
Partition panel between fuel tank and trunk removed.
Sensor removed.





Checking fuel gauge sensor
- Connect multimeter to terminal G and terminal 31 and measure resistance:



- Installation position reserve indication, float down:
80 ± 3 ohms up to 08/88
76 ± 1 ohms as of 09/88
- Sensor turned by 180° Indication full, float up:
2 ± 1 ohm up to 08/88
2 ± 1 ohm as of 09/88


Checking reserve warning contact
- Connect multimeter to terminal W and terminal 31 and measure resistance.
Nominal value approx. 0 ohms in installation position.
Nominal value infinite ohms turned 180°.

Note: The reserve warning lamp lights up with ignition switched on (control function). As soon as the engine runs, the lamp goes out provided the fuel tank contains more than the reserve amount.
In control function the reserve warning lamp lights up dimly, with reserve brightly.


Checking cable harness
- Remove coupling on fuel gauge sensor.
- Measure resistance on jack 3 and vehicle ground.



Nominal value approx. 0 ohms, with test value ground lead is interrupted.
- Measure and note resistance on terminal G and terminal 31. Sensor is installed, the value is dependent on fuel tank contents.
- Connect coupling to fuel gauge sensor.
- Remove instrument cluster, reinstall. Service and Repair
- Measure resistance .

1st version up to 09/84 on terminal 1 and terminal 15:

2nd version as of 10/54 on terminals 1 and 3:

- Nominal value measured and noted on the sensor on terminals G and 31, minor deviation possible due to length of wire.
- Measured value greater or near infinate ohms means poor contact, cold soldering point or wire interruption on the cable hamess couplings (on instrument cluster, on main cable harness/tail lamp cable harness or fuel gauge sensor).
- No fault noted during tests replace gauge.

Test Values For Gauge Sensor:

Test Values For Gauge: