Flow of Diagnosis

The procedures include all the specifications, instructions, and graphics needed to diagnose Mark 20 Antilock Braking System (ABS) and Mark 20 Antilock Braking System with Traction Control. The diagnostics are based on the failure condition or symptom being present at time of diagnosis.
Please follow the recommendations below when choosing your diagnostic path.
1. First make sure the DRBIII(R) is communicating with the CAB. If the DRBIII(R) displays a "No Response" condition, you must diagnose that first.
2. Read DTC's (diagnostic trouble codes) with the DRBIII.
3. If no DTC's are present, identify the customer complaint.
4. Once the DTC or customer complaint is identified, locate the matching test in the Table of Contents and begin to diagnose the symptom.

An * placed before the symptom description indicates a customer complaint.
When repairs are required, refer to the appropriate procedure for the proper removal and repair procedure.
Diagnostic procedures change every year. New diagnostic systems may be added; carryover systems may be enhanced. READ THIS INFORMATION BEFORE TRYING TO DIAGNOSE A VEHICLE CODE. It is recommended that you review all the information to become familiar with all new and changed diagnostic procedures.