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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 143 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING)FUEL SYSTEM (GASOLINE)FUEL PUMP RELAY (3.4L)TEST DESCRIPTION
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Test Description

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Test Description
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number in the diagnostic procedures.

  1. 2

    Command both ON and OFF states. Repeat commands as necessary.

  2. 3

    This step determines if condition is located on coil side or switch side of circuit.

  3. 4

    This step verifies PCM is providing voltage to fuel pump relay.

  4. 5

    This step tests for an open in fuel pump relay ground circuit.

  5. 6

    This step determines if voltage is constantly being applied to fuel pump relay.

  6. 12

    This tests for a grounded fuel pump supply voltage circuit. The fuel pump fuse supplies power to fuel pump. Disconnecting fuel pump in-line harness connector isolates fuel pump supply voltage circuit.

  7. 15

    This step jumps fuel pump relay in order to activate fuel pump.

  8. 16

    This step tests for an open in fuel pump feed circuit between in-line connector and fuel pump relay.

  9. 17

    This step tests for an open or high resistance in fuel pump ground circuit.

  10. 20

    This step determines if condition with circuit is intermittent. If fuse does not open, inspect supply voltage circuit between fuse and fuel pump for an intermittent condition.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.