Fuel Level Sensor: Testing and Inspection

Sending Unit and Wiring
When a problem occurs with a cluster gauge check for a defective sending unit or wiring. Do this before disassembling the cluster.
1. Sending units and wiring can be checked by grounding the connector leads at the sending unit in the vehicle.
2. With the ignition in the ON position, a grounded input will cause the fuel or temperature gauge to read at or above maximum.

Fig 10 Level Sensor Diagnosis:

Sending Unit Resistance
This procedure tests the resistance of the level sensor itself. It does not test the level sensor circuit.

The level sensor is a variable resistor. Its resistance changes with the amount of fuel in the tank.

The float arm attached to the sensor moves as the fuel level changes. To test the level sensor, connect an ohmmeter across the sensor signal and sensor ground terminals of the fuel pump module connector. Move the float lever to the positions shown in the resistance chart. Record the resistance at each point. Replace the level sensor if the resistance is not within specifications.
- Sensor Full Stop 50 - 90 ohms
- Sensor Empty Stop 1020 - 1080 ohms