Circuit/System Testing
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the fuel level sensor.
- Ignition OFF, test for less than 1 ohm of resistance between the fuel level sensor low reference circuit terminal C 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/PCM.
- Install a Signal Generator and Instrument Panel Tester between the fuel level sensor signal circuit terminal B and the fuel level sensor low reference circuit terminal C.
- Ignition ON, vary the signal generator resistance between 40 and 250 ohms. Verify that the scan tool Fuel Tank Level Remaining or Fuel Level parameter displays a range that varies between 5 and 95 percent as the signal generator resistance changes.
- If not displaying the specified range, test the signal circuit for an open/high resistance. If the circuit test normal, replace the ECM/PCM.
- 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 the gage is incorrect, replace the IPC.
- If all circuits test normal, perform the fuel level sensor component test before replacing the fuel level sensor.