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 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. After performing diagnostic system check, go to next step.
- Disconnect the purge pipe from the EVAP canister purge valve. Install a hand held vacuum gauge to the EVAP canister purge valve purge port. Disconnect the EVAP canister purge valve harness connector. Monitor vacuum on the vacuum gauge. Start engine and allow the engine to idle. Increase the idle to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to step 8 . If no, go to next step.
- Connect EVAP purge solenoid harness connector. Monitor vacuum on the vacuum gauge. Increase the idle to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to step 5 . If no, go to next step.
- Turn ignition off. Remove and then install the fuel fill cap. Turn ignition on, with engine off. Observe the Fuel Tank Pressure Sensor parameter with a scan tool. Is the fuel tank pressure sensor parameter -0.5 to +0.5 in. H2O? If yes, go to DIAGNOSTIC AIDS . If no, go to step 6 .
- Test the EVAP purge solenoid control circuit for a short to ground. Did you find and correct the conditions? If yes, go to step 9 . If no, go to step 8 .
- Test for an intermittent and for a poor connection at the EVAP purge solenoid. Did you find and correct the condition? If yes, go to step 9 . If no, go to next step.
- Replace FTP sensor. After replacing sensor, go to step 9 .
- Replace EVAP canister purge valve. After replacing purge valve, go to next step.
- Using scan tool, clear DTCs. Turn ignition off for 30 seconds Start engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step 3 .
- Using scan tool, observe stored information and capture information. Does the scan tool display any DTC's that you have not diagnosed? If yes, diagnose affected DTCs. 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.