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 Procedure
2004 Oldsmobile Bravada AWDSECTION Diagnostic Procedure
WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Many DTC related repairs will instruct technician to clear DTC information. This procedure will reset ALL I/M System Status indicators to NO and require performing I/M Complete System Set Procedure.
- Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. Repair any DTCs or driveability concerns that may prevent I/M System Status tests from completing. If DTCs or driveability concerns are found and repaired, go to step 3 . If no DTCs or driveability concerns are found and repaired, go to next step.
- Check Technical Service Bulletins (TSB) for software updates that may prevent I/M readiness. Perform any reprogramming or repairs indicated by service bulletins. When complete, go to next step.
- Using scan tool, observe the I/M System Status display for the PCM. Are any of the tests indicating NO? If yes, go to next step. If no, go to step 6 .
- Turn ignition off. Remove CNG fuse (20-amp) from underhood fuse block. Start engine and allow to idle. Using scan tool, verify engine is operating in gasoline mode. Perform necessary set procedures for I/M System Status indicators that were set to NO. When complete, go to next step.
- Turn ignition off. Reinstall CNG fuse. Start engine and allow it idle. Using scan tool, verify engine is operating in CNG mode. Perform necessary set procedures for I/M System Status indicators that were set to NO. After performing set procedures, system is okay.
- Start engine and allow to idle. Using scan tool, verify engine is operating in CNG mode. Perform necessary set procedures for I/M System Status indicators that were set to NO. After performing set procedures, 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.