CI-133 Fuel Level Signal to Trip Computer Too High

Condition:

Fuel Level/Gauge:

- Short-circuit to supply voltage in signal cable

Possible Source:
- Short-circuit to supply voltage in fuel level signal cable between combined instrument panel and trip computer.

Fault Symptom(s)
- In cars equipped with a trip computer incorrect values for "Range to empty fuel tank" and fuel consumption are displayed.

Start fault-tracing at step 1, below.

1) Status Check:

Ignition On:

- Ignition on.
- Go into scrolling values.





- Read off status of fuel level signal to trip computer.
- Is the status OK displayed?

Yes: Go to step 7, below.
No: Go to step 2, below.

2) Checking Signal From Combined Instrument Panel:

- Ignition off.

Breakout Box Between Combined Inst. Panel And Cable Harness A+B+D:

- Connect the breakout box and check ground terminals. Connecting Test (Breakout) Box





- Connect breakout box between combined instrument panel and cable harness connector A, B and D.
- Disconnect trip computer.

Ignition On:

- Ignition on.





- Connect a voltmeter between # 50 (# D4) and # 53 (# D7) on the breakout box.
- The voltmeter should oscillate between approx. 0 - 7 V.

If reading is OK, go to step 3, below.
If reading is incorrect, go to step 4, below.

3) Replacing Component:





- Try a new trip computer module. Service and Repair (Individual Component Replacement)
- Then continue with step 5, below.

4) Checking for a Short-Circuit to Supply Voltage:





- Check cable to combined instrument panel # D7 for a short-circuit to supply voltage. Permanent Fault
- Then continue with step 5, below.

5) Verification:

Note: After carrying out the repair check that the fault has been remedied.

- Ignition off.

Connect Connector:

- Reconnect connectors, reinstall components.

Ignition On:

- Ignition on.
- Go into scrolling values.





- Read off status of fuel level signal to trip computer.
- Is the status OK displayed?

Yes: Fault corrected
No: Go to step 6, below.

6) Fault-Tracing Information:
- The verification result shows that the fault persists.
- Do you want to quit fault-tracing?

Yes: Fault is not corrected!
No: Start over at step 1, above.

7) Faulty signal, Intermittent fault









- Check cable to combined instrument panel # D7 for an intermittent short-circuit to supply voltage. Intermittent Fault
- Then continue with step 8, below.

8) Fault-Tracing Information:
- For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.
- If you want to repeat fault-tracing, start over at step 1, above.