4 Channel ABS

Inspection and Verification

1. Verify the customer concern by operating the vehicle and applying the brakes under different conditions to duplicate the condition.

2. Inspect to determine if one of the following mechanical or electrical concerns apply:

Visual Inspection Chart

Mechanical
- Parking brake cable binding.
- Incorrectly inflated tires.
- Mismatched wheels or tires on vehicle.

Electrical
- Fuses.
- Loose or corroded connectors.
- Circuitry.

3. If the concern remains after the inspection, connect the diagnostic tool to the data link connector (DLC) located beneath the instrument panel, near the center, and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
- check that the program card is correctly installed.
- check the connections to the vehicle.
- check the ignition switch position.

4. If the diagnostic tool still does not communicate with the vehicle, refer to the Wiring Diagrams manual and carry out the following.
- Check circuit 70 for open, ground or short.
- Check battery feed and ground circuits at ABS module two wire connector or the ignition feed on the 24-pin connector.

5. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
- SCP or ISO = all electronic control units no response/not equipped, refer to.
- No response/not equipped for ABS module, go to diagnostic tool manual.
- System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the ABS module.

NOTE: Multiple DTCs can be stored due to voltage drop.

6. If the DTCs retrieved are related to the concern, go to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index to continue diagnostics.

7. If no DTCs related to the concern are retrieved, GO to Symptom Chart to continue diagnostics.