Symptom Related Diagnostic Procedures

DIAGNOSIS
1. Your diagnostic test procedure must begin with a thorough visual inspection of the ABS system components for damaged components or disconnected connectors. A visual inspection consists of physically looking for the possible cause of a malfunction. A careful and thorough visual inspection of components may quickly identify the cause of a malfunction and eliminate the need for diagnostic testing.

PERFORM THE FOLLOWING VISUAL INSPECTIONS BEFORE DOING ANY DIAGNOSTIC TESTING.
If a malfunction is not resolved by the visual inspection, proceed with diagnostic testing.

See (Component Locations) for pictures identifying the location of system components.

Brake Fluid Level Visually inspect for the proper fluid level within the fluid reservoir.

Hydraulic Control Unit Visually inspect the hydraulic assemblies for leaks and for damaged or disconnected connectors.

Fuses Visually inspect that all fuses are properly installed.

Wheel Speed Sensor Connector Visually inspect both front wheel speed sensor connectors for damage or disconnection. Inspect the rear axle speed sensor connectors.

Brake Fluid Lines Visually inspect brake fluid lines for any leaks or damage.

Wheel Speed Sensors Visually inspect all three wheel speed sensors and tone wheels for any damage.

Controller Antilock Brake (CAB) Visually inspect the CAB for a secure mounting and the CAB connector for damage or loose connection.

Base Brake System Visually inspect the condition of the parking brake, rotors, drums, and calipers.





2. Connect the DRBIII to the Data Link Connector (DLC).
3. With the DRBIII, read Kelsey-Hayes ABS active and stored trouble codes and record them. If you encounter a "NO RESPONSE" message on the DRBIII while accessing the Kelsey-Hayes ABS diagnostic menu, perform DRB No Response Message test. For other DRBIII related communication problems, refer to the Vehicle Communications test. If a wheel speed sensor code was present, perform the test(s) indicated. Using the DRBIII, either reset the module to erase all stored trouble codes or use the erase command after reading all diagnostic trouble codes.
4. Turn ignition off, then on. If the diagnostic trouble code doesn't come back, refer to the diagnostic trouble code description. If the DRBIII displays diagnostic trouble codes, proceed to the appropriate diagnostic test(s). If no diagnostic trouble codes are present at the time, perform the System Verification Test. Verification Tests

WARNING: Before performing any road test, verify that full braking capability is present.