SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 143 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING)FUEL SYSTEM (GASOLINE)FUEL INJECTOR CIRCUIT DIAGNOSIS (4.2L)DIAGNOSTIC PROCEDURE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Diagnostic Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Procedure
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.
  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Are any fuel injector DTCs set? If yes, go to DTC P0201-P0206: FUEL INJECTOR CONTROL CIRCUIT under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. If no, go to next step.
  3. Turn OFF the ignition. Disconnect multi-way harness connector of fuel injectors. Turn ON the ignition, with the engine OFF. Probe Ignition 1 Voltage Supply circuit of fuel injector, fuse side, with test light connected to a good ground. Does test light illuminate? If yes, go to next step. If no, go to step  5.
  4. Test for continuity between Ignition 1 voltage supply terminal and a fuel injector terminal, at multi-way harness connector, fuel injector side. Does DMM display OL? If yes, go to step  6. If no, go to step  7.
  5. Repair open in Ignition 1 Voltage Supply circuit between PCM 1 fuse and multi-way connector. After repairs, go to step  8.
  6. Repair Ignition 1 Voltage Supply circuit of fuel injectors for an open or high resistance, between multi-way connector and splice. After repairs, go to step  8.
  7. Repair poor connection at multi-way harness connector. After repairs, go to next step.
  8. Operate system in order to verify repair. Did you correct the condition? If yes, system is okay. If no, go to step  3.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

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.