Introduction to A/T Diagnosis

The procedures contained include specifications, instructions, and graphics needed to diagnose the AW4 AUTOMATIC TRANSMISSION. The diagnostics are based on the failure condition or symptom being present at the time of diagnosis.
Please follow the recommendations below when choosing your diagnostic path.
1. First make sure the DRBIII (R) is communicating with the appropriate modules; ie., if the DRBIII (R) displays a "No Response" condition, you must diagnose this first before proceeding.
2. Read DTC's (diagnostic trouble codes) with the DRBIII (R).
3. If no DTC's are present, identify the customer complaint.
4. Once the DTC or customer complaint is identified, locate the matching test to diagnose the symptom.

When repairs are required, refer to the appropriate removal and repair procedure.
Diagnostic procedures change every year. New diagnostic systems may be added; carryover systems may be enhanced. READ Description and Operation BEFORE TRYING TO DIAGNOSE A VEHICLE CODE. It is recommended that you review the entire Description and Operation to become familiar with all new and changed diagnostic procedures.