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.
Test Description
2004 Oldsmobile Bravada RWDSECTION Test Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 3: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
- 4: Determine if the Instrument Cluster or Powertrain Control Modules have set DTCs which may affect Engine Cooling operation are present.
- 5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Diagnostic System Check - Engine Cooling
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review a Diagnostic Starting Point-Engine Cooling? | Go to Step 2 | Go to Diagnostic Starting Point - Engine Cooling |
| 2 | Install a scan tool. Does the scan tool power up? |
Go to Step 3 | Go to Scan Tool Does Not Power Up in Data Link Communications |
| 3 |
|
Go to Step 4 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications |
| 4 | Select the powertrain control module display DTCs function on the scan tool. Does the scan tool display any DTCs? |
Go to Step 5 | Go to Symptoms - Engine Cooling |
| 5 | Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 6 |
| 6 | Does the scan tool display any DTCs that are associated with the Engine Cooling System? | Go to Diagnostic Trouble Code (DTC) List | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 4.8L, 5.3L, and 6.0L or Diagnostic Trouble Code (DTC) List in Engine Controls - 8.1L |
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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.