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
2006 Isuzu Ascender S, 5.3 M, 4WDSECTION Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. 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.
- 2: 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. First design uses a class 2 amplifier, 2nd design uses a non-class 2 amplifier.
- 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 - Entertainment System
| Step | Action | Yes | No |
|---|---|---|---|
| 1 |
|
Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications |
| 2 | Attempt to establish communication with the following:
Does the scan tool communicate with the radio, amplifier, BCM, auxiliary HVAC control module, and DRR? |
Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device (W/O Immobilizer)Scan Tool Does Not Communicate with Class 2 Device (W/ Immobilizer) in Data Link Communications |
| 3 |
IMPORTANT:
The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
|
Go to Step 4 | Go to Power Mode Mismatch in Body Control System |
| 4 | Select the following display DTCs function on the scan tool:
Does the scan tool display any DTCs? |
Go to Step 5 | Go to Symptoms - Entertainment |
| 5 | Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device (W/O Immobilizer)Scan Tool Does Not Communicate with Class 2 Device (W/ Immobilizer) in Data Link Communications | Go to Step 6 |
| 6 | Does the scan tool display DTC B1000? | Go to Diagnostic Trouble Code (DTC) List in Body Control System | Go to Step 7 |
| 7 | Does the scan tool display DTC B1327? | Go to Diagnostic Trouble Code (DTC) List in Engine Electrical | Go to Diagnostic Trouble Code (DTC) List |
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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.