Description

ADDITIONAL REFERENCES
Refer to all technical service bulletins that pertain to transmission concerns and follow the procedures.

ON-BOARD DIAGNOSTICS WITH NGS
The specific Quick Test Sub Routines are in Computers and Control Systems Testing and Inspection. These tests can be used to diagnose the Powertrain control module (PCM), sensors and actuators of the 4R70W transmission. The following tests are a guide for using the On-Board Diagnostic (OBD) Quick Tests and the Rotunda New Generation Star Tester (NGS) 007-00500, with some special considerations to remember.

NOTE: For more detailed instructions and other diagnostic methods using the NGS or a generic scan tool, refer to Computers and Control Systems Testing and Inspection for instructions on performing OBD procedures.

PROCEDURAL STEPS
Diagnosing an electronically controlled 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 BEEN MADE. Follow the procedures as written to avoid missing critical components or steps. By following the diagnostic sequence, the service technician will be able to diagnose and repair the concern the first time.

PERFORM QUICK TEST 2.0
After a road test, with the vehicle warm and before disturbing any connectors, perform Quick Test 2.0 using the NGS or equivalent.

OTHER NGS FEATURES
For further information on other diagnostic testing features using the NGS or generic scan tool, refer to Powertrain Management. Other diagnostic methods include the following:
- Parameter Identification (PID) Access Mode, used to monitor sensors and actuators.
- Freeze Frame Data Access Mode, used to view emission related data values from specific PID's.
- Oxygen Sensor Monitor Mode, used to monitor the Heated Oxygen (HO2S).

STEPS AFTER ON-BOARD DIAGNOSTICS

NOTE: The vehicle wiring harness, PCM and non-transmission sensors may affect transmission operations. Service these concerns first.

NOTE: After electrical diagnosis has been performed and a concern still exists, refer to the Diagnosis by Symptom Index. [1][2]Diagnosis By Symptom Index

- Begin with non-transmission related DTCs, then service any transmission related DTCs. Refer to the On-Board Diagnostic Trouble Code Description Chart for information on condition and symptoms. This chart will be helpful in referring to the proper tests and to aid in diagnosing internal transmission concerns and external non-transmission inputs.
- The pinpoint tests are used in diagnosing electrical concerns of the 4R70W transmission. Make sure that the vehicle wiring harness and the Powertrain control module are diagnosed as well.

BEFORE PINPOINT TESTS

NOTE: Prior to entering pinpoint tests, check the PCM wiring harness for proper connections, bent or broken pins, corrosion, loose wires, proper routing, proper seals and their condition. Check the PCM, sensors and actuators for damage.

- If DTCs appear, while performing the on-board diagnostics, refer to the On-Board Diagnostic Trouble Code Description Chart for the appropriate service procedure. Prior to entering the pinpoint tests, refer to any TSB's for 4R70W transmission concerns.