Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 241 (ENGINE CONTROL SYSTEM & ENGINE COMPONENT TESTS - 2.2L)FUEL SYSTEMSFUEL INJECTOR CIRCUIT DIAGNOSISDIAGNOSTIC PROCEDURES
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Diagnostic Procedures
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
- Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK -- ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article. After performing Diagnostic System Check - Engine Controls, go to next step.
- Is DTC P0201, P0202, P0203 or P0204 set? If yes, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.2L SONOMA & S10 PICKUP article. If no, go to next step.
- Turn ignition off. Disconnect fuel injector harness connector. Turn ignition on, with engine off. Using a test light connected to ground, probe fuel injector ignition 1 voltage circuit (fuse side). Does test light illuminate? If yes, go to next step. If no, go to step 5.
- Using a DVOM, measure resistance from the ECM 1 fuse to the ignition 1 voltage circuit terminal of a fuel injector. Is resistance greater than 5 ohms, go to step 6. If no, problem is intermittent.
- Repair open in the ignition 1 voltage circuit of the fuel injectors. After repairs, go to step 7.
- Repair high resistance in the ignition 1 voltage circuit of the fuel injectors. After repairs, go to next step.
- Operate the system in order to verify the 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.
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.