Diagnostics

Diagnostics
^ Carry out on-board diagnostic procedures key ON/engine OFF (KOEO) and key ON/engine running (KOER).
^ Record all DTCs.
^ Repair all non-transmission codes first.
^ Repair all transmission codes second.
^ Erase all continuous codes and attempt to repeat them.
^ Repair all continuous codes.
^ If only pass codes are obtained, refer to Diagnosis By Symptom for further information and diagnosis. Symptoms

Follow the diagnostic sequence to diagnose and repair the concern the first time.








Diagnosing an electronically controlled automatic transmission is simplified by using the following procedures. One of the most important things to remember is that there is a definite procedure to follow. DO NOT TAKE SHORT CUTS OR ASSUME THAT CRITICAL CHECKS OR ADJUSTMENTS HAVE ALREADY BEEN MADE. Follow the procedures as written to avoid missing critical components or steps. By following the diagnostic sequence, the technician will be able to diagnose and repair the concern the first time.

On-Board Diagnostics With Scan Tool

NOTE: For detailed instruction and other diagnostic methods using the scan tool, refer to the scan tool tester manual and Computers and Control Systems. These quick tests should be used to diagnose the PCM and should be carried out in order.

^ Quick Test 1.0 - Visual Inspection
^ Quick Test 2.0 - Set Up
^ Quick Test 3.0 - Key ON, Engine OFF (KOEO)
^ Quick Test 4.0 - Continuous Memory
^ Quick Test 5.0 - Key ON, Engine Running (KOER)
- Special Test Mode
- Wiggle Test
- Output Test Mode
- PCM Reset Mode
- Clearing DTCs
- OBD II Drive Cycle
^ Other Scan Tool Features

For further information on other diagnostic testing features using the scan tool, refer to Computers and Control Systems. Other diagnostic methods include the following:
- PID Access Mode
- Freeze Frame Data Access Mode
- Oxygen Sensor Monitor Mode