Reading and Clearing Diagnostic Trouble Codes

Diagnostics

Special Tool(s):

Diagnosing electronically controlled automatic transmissions is simplified using the following procedures. It is important to remember that there is a definite procedure to follow. Do not take shortcuts 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 Diagnostic Tool

NOTE: For detailed instruction and other diagnostic methods using the diagnostic tool, refer to the diagnostic tool tester manual and Computers and Control systems.

These quick tests should be used to diagnose the powertrain control module (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
^ Quick Test 4.0 - Continuous Memory
^ Quick Test 5.0 - Key On, Engine Running
^ Special Test Mode
- Wiggle Test Mode
- Output Test Mode
^ PCM Reset Mode
^ Clearing DTCs
^ OBD II Drive Cycle

For further information on other diagnostic testing features using the WDS or generic diagnostic tool, refer to Computers and Control systems.