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.
- Is the cooling system low on coolant? If yes, repair coolant loss. If no, go to next step.
- Turn off the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Turn on the ignition, with the engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step 5.
- Turn off the ignition. Disconnect the IAT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the IAT sensor. Turn on the ignition, with the engine off. Observe the IAT sensor temperature with a scan tool. Does the scan tool indicate that the IAT sensor temperature is more than 280°F (138°C)? If yes, go to step 8. If no, see DIAGNOSTIC AIDS .
- Turn off the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and of a known-good ground. Turn on the ignition, with the engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step 7.
- Test the ECT sensor low reference circuit for a high resistance or for an open. Repair the circuit as necessary. After repairs, go to step 11.
- Test the ECT sensor signal circuit for a high resistance or for an open. Repair the circuit as necessary. After repairs, go to step 11.
- Remove the ECT sensor. Suspend the ECT sensor and a thermometer in a pan of water. Place the pan on a burner or on a hot plate. Test the resistance of the ECT sensor through the specified range of temperatures. See TEMPERATURE VS RESISTANCE table in appropriate SENSOR OPERATING RANGE CHARTS article. Do the resistance and temperature closely match the Temperature vs Resistance table? If yes, go to next step. If no, go to step 10.
- Reinstall the ECT sensor. After installation, see DIAGNOSTIC AIDS .
- Replace the ECT sensor. 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.
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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.