Pinpoint Test B: Fuel Level Sensor Tests

1. Locate the fuel pump module flange electrical connectors. (Refer to: FUEL PUMP AND SENDER UNIT )
2. Disconnect and reconnect the fuel level sensor electrical connector three times

Did the datalogger signals change between 0.37V and 3.02V each time the connector was disconnected and reconnected?

• Yes  : Poor connection in the fuel pump electrical connector or harness side electrical connector due to damaged/corroded connector pins or pin receptacles. If the bad connection is on the harness side connector or the wiring before fuel pump module flange, replace the wiring or connector. If the bad connection is on the fuel pump module flange connector, install a new fuel pump module (Refer to: FUEL PUMP AND SENDER UNIT .
• No: GO to B2  .

1. Disconnect the fuel level sensor electrical connector from the fuel pump module flange
2. Check if all the fuel pump module flange pins are projecting sufficiently to ensure electrical contact. Each pin is required to be 11.6mm from the top of the connector molding
3. Check if the harness electrical connectors are correctly located, not disconnected, damaged or pins are backed out

Is there any evident fault in the flange electrical connector pins or harness electrical connector?

• Yes  : Repair as necessary
• No: GO to B3  .

1. Connect an ohmmeter to the passive fuel level sensor (B) terminals in the fuel pump module flange connector (Pins 2 PASSIVE + and 4 PASSIVE -)
2. Measure the resistance of the passive fuel level sensor (B)
3. Connect an ohmmeter to the active fuel level sensor (A) terminals in the fuel pump module flange connector (Pins 5 ACTIVE + and 3 ACTIVE -)
4. Measure the resistance of the active fuel level sensor (A)
5. Make a note of the resistance values

Is the measured resistance of the fuel level sensors between 51.1Ω and 992.1Ω?

• Yes  : Refer to: Electrical information (Electrical wiring diagram, Fuel tank and fuel line) and check the fuel level sensor circuit Central Junction Box (CJB) to fuel pump module flange and CJB to Instrument Cluster (IC) for short circuit to ground, short circuit to power, open circuit, high resistance. Repair circuit as necessary. Re-configure the IC with the latest level software. Re-configure the CJB
• No: GO to B4  .

Two ohmmeters are required for this test.

1. Disconnect the battery. (Refer to: Battery Disconnect And Connect .
2. Disconnect the battery support unit
3. Remove the fuel pump module flange (to allow access to the connector on the underside of the fuel pump module flange. (Refer to: Fuel tank and lines 
4. Connect an ohmmeter to the passive fuel level sensor (B) terminals in the fuel pump module flange connector (Pins 2 PASSIVE + and 4 PASSIVE -)
5. Connect an ohmmeter to the active fuel level sensor (A) terminals in the fuel pump module flange connector (Pins 5 ACTIVE + and 3 ACTIVE -)
6. Measure the resistance of the passive fuel level sensor (B)
7. Measure the resistance of the active fuel level sensor (A)
8. Disconnect and reconnect the fuel pump module lower fuel level electrical connector three times
9. Check if there is any evidence of frayed, melted wires/connectors or corroded connector pins

Did the measured resistance values change between 51.1Ω and 992.1Ω each time the connector was disconnected and reconnected?

• Yes  : Poor connection in the fuel pump module electrical connector due to damage/corrosion of the terminals. Install a new low pressure fuel pump. (Refer to: FUEL PUMP AND SENDER UNIT .
• No: GO to B5  .

1. Disconnect both the active (A) and passive (B) fuel level electrical connector from the underside of the fuel pump module
2. Measure the resistance of the passive fuel level sensor (B)
3. Measure the resistance of the active fuel level sensor (A)

Is the measured resistance of the fuel level sensors between 51.1Ω and 992.1Ω?

• Yes  : Poor connection in the fuel pump flange electrical connector due to damage/corrosion of the terminals. Install a new low pressure fuel pump. (Refer to: FUEL PUMP AND SENDER UNIT )
• No: GO to B6  .

If the measurement range of the ohmmeter is set to 'automatic', the ohmmeter will briefly display 'open circuit' when the range changes. This does not indicate a fault with the component. To prevent incorrect diagnosis, always set the measurement range to 'manual'

1. Remove the suspect fuel level sensor
2. Connect an ohmmeter to the fuel level sensor terminals
3. Move the fuel level sensor arm through its full range and monitor the measured resistance

Is the measured resistance for the active fuel level sensor (A) between 51.1Ω and 992.1Ω? Is the measured resistance for passive fuel level sensor (B) between 51.1Ω and 992.1Ω?

• Yes  : Active fuel level sensor (A) Check the fuel level sensor float arm for breakage or bends. Replace the active fuel level sensor (A) Passive fuel level sensor (B) Check the fuel level sensor float arm for breakage or bends. Replace the passive fuel level sensor (B)
• No  : Active fuel level sensor (A) Fuel level sensor internal failure. Install a new active fuel level sensor (A) Passive fuel level sensor (B) Fuel level sensor internal failure. Install a new passive fuel level sensor (B)