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B1720

Symptom: The fuel gauge shows empty.The low fuel warning lamp lights up.Some of the trip computer's functions are affected.

B1720

Fuel level transmitter signal faulty

Fault symptom

The fuel gauge shows empty.

The low fuel warning lamp lights up.

Some of the trip computer's functions are affected.



Diagnostic procedure



1. Connect the ISAT Scan Tool and select "READ VALUES" followed by "TANK CONTENTS".

2. If the fuel level sensor signal is OK, the reading shown on the ISAT Scan Tool's display should correspond to the contents of the fuel tank. If this is the case, continue with point 7.

3. If the display shows tank contents = 0, the fuel level sensor signal sent to the main instrument display panel is faulty. In this case, continue by checking the fuel level sensor, point 4.

4. Unplug the fuel level sensor's connector, which is located under a cover under the rear seat, and take a resistance reading across the pins. The correct resistance is between 50 and 390 ohms. If the resistance is outside this range, the transmitter or its connecting lead is at fault. Check and take the necessary action.



5. If the resistance reading is OK, the fault is probably in the wiring between the fuel level sensor and the main instrument display panel.


To check this, connect a BOB to the main instrument display panel's 56-pin connector. The main instrument display panel should not be connected.

6. Plug in the fuel level sensor's connector again.

Take a reading across pins 11 and 12 on the BOB to check for continuity/shorting.

The correct resistance across the pins is between 50 and 390 ohms. If this is the case, continue with point 7.

If the reading obtained is outside this resistance range the wiring is faulty. Investigate the cause and rectify.

7. Disconnect the BOB and connect the main instrument display panel. Clear the diagnostic trouble code and see whether it recurs.


If it does not recur, the fault could have been in one of the connectors.

If the trouble code recurs, there may be an open circuit between the connector and the processor in the main instrument unit control module. Continue fault diagnosis as described on .