Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the primary (left) and secondary (right) fuel level sensors.
- Ignition OFF, test for less than 1 ohm of resistance between the primary (left) fuel level sensor low reference circuit terminal D and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuits tests normal, replace the ECM.
- Ignition OFF, test for less than 1 ohm of resistance between the secondary (right) fuel level sensor low reference circuit terminal D and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuits tests normal, replace the ECM.
- Jumper the primary (left) fuel level sensor signal circuit terminal A to the secondary (right) fuel level sensor signal circuit terminal A. Install a Signal Generator and Instrument Panel Tester between the jumped signal circuits and ground.
- Ignition ON, vary the signal generator resistance between 40 and 250 ohms. 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 displaying the specified range, test both signal circuits for an open/high resistance. If the circuits test normal, replace the ECM.
- Vary the signal generator resistance between 40 and 250 ohms. Verify that the fuel gage displays a range that varies between empty and full as the signal generator resistance changes.
- If all circuits test normal, perform the fuel level sensor component test before replacing either the primary or secondary fuel level sensor.