LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2003 >> Silverado 1500 HD, RWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> ENGINE CONTROLS - SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline >> Diagnostic Tests >> DTC P1172: Secondary Fuel Pump Transfer Malfunction >> Test Description

Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 2

    This step tests the supply voltage circuit of the secondary fuel pump relay.
  2. 4

    This step verifies the secondary fuel pump operation. Listen for an audible sound as the secondary fuel pump relay harness connector is jumpered.
  3. 5

    This step verifies that there is adequate fuel in the rear fuel tank. The rear fuel tank sensor voltage must be above 1 volt in order to continue.
  4. 7

    This step tests the secondary fuel pumps ability to transfer fuel. The rear fuel level sensor voltage should decrease while the secondary fuel pump is ON.
  5. 8

    This step tests for a short to ground on the control circuit of the secondary fuel pump relay.
  6. 9

    This step tests for a short to voltage on the control circuit of the secondary fuel pump relay.
  7. 10

    This step verifies the secondary fuel pump relay operation. An audible click should be heard as the secondary fuel pump relay control circuit is grounded. The secondary fuel pump should turn ON as the fuel pump relay control circuit is grounded.