Table of contents: Malfunction of fuel quantity… ↓ Is your fuel gauge or fuel level… ↓ Checking and adjusting the fuel… ↓
The fuel level is shown electrically on the dashboard.
The deflection of the fuel gauge needle is changed by contact with the ground. This is ensured by the fuel level sensor, which has a higher or lower resistance depending on how full the fuel tank is. The voltage supply and signal preparation for the fuel level sensor is provided by the central microprocessor of the combined instrument panel. Information on dismantling the fuel level sensor can be found in the chapter Fuel tank and fuel pump.
Malfunction of fuel quantity indicator
High or low readings: fuel level sensor float is not installed correctly (see next section), or amendments are not installed (V.A.G 1551).
No reading: Incoming voltage is outside the range of the combination instrument, or the level sensor or indicator is faulty.
Is your fuel gauge or fuel level sensor faulty?
1. Expose the fuel level sensor wire connectors (chapter Fuel tank and fuel pump), disconnect the multi-pin connector.
2. Connect the auxiliary wire to the purple/black wire connector and apply it directly to ground.
3. Turn on the ignition briefly.
4. If the indicator arrow deflects completely, then the supply wire and the indicator itself are OK. Then the cause of the malfunction remains the fuel level sensor.
5. If the pointer remains in the "empty" position, the fault is in the supply wire, in the combined instrument wire, or in the fuel quantity indicator. The fuel level sensor is probably OK.
Checking and adjusting the fuel indicator
1. Expose the fuel level sensor wire connectors.
2. Disconnect the connector and measure the resistance at the fuel level sensor connector with an ohmmeter:
3. Tank full: 40 Ohm.
4. Tank half full: 115 Ohm.
5. Tank reserve: 250 Ohm.
6. If the obtained measurement results are completely different from the specified ones, then: the fuel level sensor is faulty.
7. If the measurement results are OK, but the fuel quantity indicator readings have a large error or there is no indication, then: there is no conductivity or the device is faulty.
8. The measurement results are close or the indicator is inaccurate: the fuel level sensor float is incorrectly adjusted.
9. Installing the fuel level sensor float: This is a job for a workshop that can perform the adjustment using the VAG 1551 error reading device. Within certain limits, the following can be done:
10. Remove the fuel level sensor.
11. If the fuel quantity indicator overstates the data, then: slightly bend the float lever upwards.
12. If the fuel level indicator shows lower readings, then: slightly bend the float lever down.
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