Diagnostic Strategies

AUTOMATIC TRANSMISSION DIAGNOSTIC TROUBLESHOOTING STRATEGY
Use these steps to plan your diagnostic strategy. If you follow them carefully, you will be sure that you have exhausted most of the possible ways to find an A/T fault.
1. Gather as much information as possible about the complaint from the customer.
2. Verify that the condition described by the customer exists.
3. Check the vehicle for any A/T Diagnostic Trouble Code (DTC).
4. If you cannot verify the condition and there are no DTCs, the malfunction is intermittent. For information on how to cope with intermittent malfunctions, refer to How to Use Troubleshooting/Inspection Service Points.
5. If you can verify the condition but there are no DTCs, or the system cannot communicate with the scan tool, refer to the Symptom Chart. Symptom Chart
6. If there is a DTC, record the number of the code, then erase the code from memory using the scan tool.
7. Reconfirm the symptom using the Road Test.
8. If DTC is set again, go to Inspection Chart for Diagnostic Trouble Codes. Diagnostic Trouble Code Descriptions
9. If DTC is not set again, the malfunction is intermittent. For information on how to cope with intermittent malfunctions, refer to How to Use Troubleshooting/inspection Service Points.
10. After repairs are completed, conduct a Road Test duplicating the complaint set conditions to confirm the malfunction has been eliminated.