Diagnostics

4R70E/4R75E

Diagnostics





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 Diagnostic (OBD) 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 Information. These self tests should be used to diagnose the PCM and should be carried out in order.

- Visual Inspection
- Set Up Self Test
- Key ON Engine OFF (KOEO)
- All Continuous Memory DTCs
- Key ON Engine Running (KOER)
- Wiggle Test
- Network Test
- Reset KAM
- Clearing DTCs
- OBD Drive Cycle

- Other Scan Tool Features

For further information on other diagnostic testing features using the scan tool, refer to Computers and Control Systems Information. Other diagnostic methods include the following:

- PID Access Mode
- Freeze Frame Data Access Mode
- Oxygen Sensor Monitor Mode