LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1647 (Engine Control System & Fuel System - 4.8L, 5.3L, 6.0L, 6.2L - DTC P1255 To DTC P3449) >> DTC P2635 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify that DTCs P018C, P018D, P0231, P0232, or P023F are not set.
  2. Ignition OFF, disconnect the harness connector at the G12 fuel pump.
  3. Ignition OFF, test for less than 5.0 Ω between the G12 fuel pump low reference circuit terminal A and ground.
    • If greater than the specified range, test the G12 fuel pump low reference circuit for a high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  4. Ignition OFF, install a test lamp between the control circuit terminal D and the low reference circuit terminal A.
  5. Ignition ON, command the Fuel Pump Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  6. Perform the Fuel System Diagnosis (Without FPCM) or Fuel System Diagnosis (FPCM) to verify proper fuel pressure.
    • If the fuel pressure is not normal, replace the G12 fuel pump
  7. If all circuits test normal, replace the K27 fuel pump control module.
scientia non olet · About LEMON Manuals