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.
Diagnostic Procedures
2004 Oldsmobile Bravada AWDSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2002 GMC Savana and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
- Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM.
- Clear the DTCs with a scan tool. Idle the engine at the normal operating temperature. Monitor the misfire current counters with a scan tool. Are any of the counters incrementing? If yes, go to step 4. If no, go to next step.
- Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
- Turn OFF the ignition. Remove the engine cover. Disconnect the fuel injector harness connector. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage supply circuit of the appropriate fuel injector with a test lamp that is connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step 11.
- Connect the J 34730-375 Injector Test Lamp between the control circuit and the ignition 1 voltage supply circuit of the appropriate fuel injector. Crank the engine. Does the test lamp flash? If yes, go to step 9. If no, go to next step.
- Does the test lamp remain illuminated at all times? If yes, go to step 8. If no, go to next step.
- Test the control circuit of the fuel injector for an open and for a short to voltage. Did you find and correct the condition? If yes, go to step 14. If no, go to step 10.
- Test the control circuit of the fuel injector for a short to ground. Did you find and correct the condition? If yes, go to step 14. If no, go to step 13.
- Inspect for poor connections at the harness connector of the fuel injector. Did you find and correct the condition? If yes, go to step 14. If no, go to step 12.
- Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 14. If no, go to step 13.
- Repair the ignition 1 voltage supply circuit of the fuel injector for an open or for a short to ground. After repairs, go to step 14.
- Replace the fuel injector. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14.
- Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE under PROGRAMMING. After repairs, go to next step.
- Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2.
- Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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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.