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 is about a different car, the 2007 Isuzu Ascender, 2007 GMC Envoy, 2007 Chevrolet TrailBlazer, and 2007 Buick Rainier. 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.
- 1: This step determines if the malfunction is present.
- 3: This step tests for an open in the vehicle speed signal circuit between the IPC and the navigation radio. A short would cause the IPC to malfunction as well as the navigation system.
DTC B0004
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Radio/Navigation System Schematics | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go Diagnostic System Check - Vehicle |
| 2 | Verify the instrument panel cluster (IPC) speedometer operation. Does the speedometer work on the IPC? |
Go to Step 3 | Go to Diagnostic Starting Point - Displays and Gages |
| 3 | Test the vehicle speed signal circuit for an open between the IPC and the navigation radio. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
Go to Step 6 | Go to Step 4 |
| 4 | Inspect for poor connections at the harness connector of the navigation radio. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
. Did you find and correct the condition? |
Go to Step 6 | Go to Step 5 |
| 5 | Replace the navigation radio. Refer to Control Module References
for replacement, setup and programming. Did you complete the replacement? |
Go to Step 6 | - |
| 6 |
|
Go to Step 2 | System OK |
RENDER: 1.0x
NO RELATED
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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.