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 RWDSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Cadillac Seville and 2003 Cadillac DeVille. 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.
- Observe the Freeze Frame/Failure Records for this DTC. Perform the Service Bay Test. See SERVICE BAY TEST under DRIVE CYCLES. Does the scan tool indicate that the Service Bay Test passed? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
- Turn ignition off. Disconnect the purge line from the EVAP purge solenoid. Turn ignition on, with engine off. Is the FUEL TANK PRESSURE SENSOR parameter within -1 to 1 in. H2O? If yes, go to next step. If no, go to step 5.
- Install a hand held vacuum gage to the EVAP purge port. Disconnect the EVAP canister purge valve harness connector. Monitor vacuum on the vacuum gage. Start the engine and allow the engine to idle. Increase the idle to 1200-1500 RPM. Does the vacuum gage indicate an increase in vacuum? If yes, go to step 7. If no, see DIAGNOSTIC AIDS .
- Test for an intermittent and/or poor connections at the FTP sensor. Did you find and correct the condition? If yes, go to step 8. If no, go to next step.
- Replace the FTP sensor. See FUEL TANK PRESSURE SENSOR under SENSORS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement?
- Replace the EVAP canister purge solenoid. Refer to Evaporative Emission (EVAP) Canister Vent Valve Replacement. Did you complete the replacement? If yes, go to next step.
- Perform the Service Bay Test. See SERVICE BAY TEST under DRIVE CYCLES. Does the scan tool indicate that the Service Bay Test passed? If yes, go to next step. If no, go to step 3.
- Observe the Capture Info with a scan tool. Are there any DTCs that have not been 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.