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 does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 Buick Regal. 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 - Engine Controls, go to next step.
- Turn ignition on. If DTC P0403 or P0405 is not present, using scan tool, command EGR valve from zero to 100 percent. Does the EGR position sensor remain within 15 percent of the desired EGR position at all commanded positions? If yes, go to next step. If no, go to step 4.
- Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC or as close to FREEZE FRAME/FAILURE RECORDS data as possible. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
- Turn ignition off. Disconnect EGR. Turn ignition on, engine off. Using scan tool, observe EGR position sensor parameter. Does the scan tool indicate that the EGR position sensor is zero percent? If yes, go to next step. If no, go to step 8.
- Measure the voltage from the 5-volt reference circuit of the EGR position sensor to the ground circuit of the EGR position sensor. Does the DMM display voltage near 5 volts? If yes, go to next step. If no, go to step 7.
- Connect a fused jumper between the 5-volt reference circuit of the EGR position sensor and the EGR pintle position signal circuit of the EGR position sensor. Does the scan tool indicate that the EGR position sensor is near 100 percent? If yes, go to step 12. If no, go to step 10.
- Measure the voltage from the 5-volt reference circuit of the EGR position sensor to a good ground. Does the DMM display voltage near 5 volts? If yes, go to step 9. If no, go to step 11.
- Test the EGR pintle position signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 16. If no, go to step 13.
- Check EGR position sensor ground circuit for open or high resistance. Did you find and correct the condition? If yes, go to step 16. If no, go to step 13.
- Check EGR signal circuit for high resistance or high resistance short to ground. Did you find and correct the condition? If yes, go to step 16. If no, go to step 14.
- Check EGR 5-volt reference circuit for open, short to ground, or short to voltage. Did you find and correct the condition? If yes, go to step 16. If no, go to step 14.
- Inspect for poor connections at the harness connector of the EGR valve. Did you find and correct the condition? If yes, go to step 16. If no, go to step 14.
- Check PCM connectors for poor connections. Did you find and correct the condition? If yes, go to step 16. If no, go to step 15.
- Replace EGR valve. After repairs, go to step 16.
- Replace PCM. Program replacement PCM. See POWERTRAIN CONTROL MODULE under PROGRAMMING. After repairs, go to next step.
- Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step 2.
- Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
NOTE:
Using scan tool, check if DTC P0403 or P0405 is present. If either of these DTCs are present, diagnose these DTCs first. See DTC P0403: EGR SOLENOID CONTROL CIRCUIT or DTC P0405: EGR POSITION SENSOR CIRCUIT - LOW VOLTAGE
.
NOTE:
If fuse blows, locate and repair a short to ground in signal circuit.
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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.