P1172 GMC Possible Causes
- Faulty fuel pump
- Fuel pump wiring harness is open or shorted
- Poor electrical connection in the fuel pump circuit
How is P1172 GMC Code Repaired?
Start by checking the “possible causes” listed above. Visually inspect the wiring harness and corresponding connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Engine light on (or engine service warning light soon)
P1172 GMC Meaning
The fuel pump is located on the left frame rail between the fuel tanks. The Engine Control Module (ECM) provides positive ignition voltage to the coil side of the fuel pump relay. The ECM activates the fuel pump relay, which powers the fuel pump. Fuel is transferred from the rear fuel tank to the front fuel tank to ensure that all usable fuel volume is available to the engine. This Diagnostic Trouble Code (DTC) is set when the ECM commands the transfer fuel pump on and a predetermined change in the front and rear fuel level sensors does not occur.