Circuit/System Testing
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. 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 1.0 ohm between the low reference circuit terminal B and ground.
- 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 C and the low reference circuit terminal B.
- Ignition ON, vary the signal generator resistance between 40-250 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 within the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
- Vary the signal generator resistance between 40-250 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.
NOTE:
If equipped, the following tests can be performed at an inline connector. See Schematic and Routing Diagrams for the corresponding terminals to test at.