Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel level sensor.
- Ignition OFF, test for less than 1 Ω between the low reference circuit terminal listed below and ground.
- Low Reference Terminal B (5.3L)
- Low Reference Terminal C (4.3L, 4.8L or 6.0L)
- Low Reference Terminal C (6.6L Diesel)
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Install a Signal Generator and Instrument Panel Tester between the signal circuit terminal and the low reference circuit terminal listed below:
- Signal Terminal C (5.3L)
- Low Reference Terminal B (5.3L)
- Signal terminal B (4.3L, 4.8L or 6.0L)
- Low Reference Terminal C (4.3L, 4.8L or 6.0L)
- Signal Terminal B (6.6L Diesel)
- Low Reference Terminal C (6.6L Diesel)
- Ignition ON, vary the signal generator resistance between 40 and 250 Ω. Verify that the scan tool Fuel Tank Level Remaining parameter displays a range that varies between 5 and 95 percent as the signal generator resistance changes.
- If not within the specified range, test the signal circuit for an open/high resistance. If the circuit test normal, replace the ECM.
- If all circuits test normal, perform the fuel level sensor component test before replacing the fuel level sensor.