Circuit/System Testing (w/o LY6, LMG, LC9)
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.
- With the ignition OFF, disconnect the harness connector at the FPCM.
- With the ignition ON, engine OFF, probe the control circuit of the fuel pump control module terminal 13 with a test lamp that is connected to a good ground. Command the fuel pump ON and OFF with a scan tool. The test lamp should turn ON and OFF with each command.
- If the test lamp does not turn ON and OFF, test for an open, high resistance, or a short to ground in the fuel pump relay control circuit, an intermittent or a poor connection at the engine control module (ECM). If the circuit tests normal, replace the control module.
- If the test lamp remains illuminated with each command, test for a short to voltage in the control circuit of the fuel pump relay or an intermittent or a poor connection at the ECM. If the circuit tests normal, replace the control module.
- If all circuits test normal, replace the FPCM.