Displaying & Reading Trouble Codes
Diagnostics
Special Tools
The following procedures are provided for use with a Rotunda New Generation STAR (NGS) Tester. For procedures using a generic scan tool, refer to Powertrain Management/Computers and Control Systems.
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 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 service technician will be able to diagnose and repair the concern the first time.
On-Board Diagnostics With NGS
NOTE: For detailed instructions and other diagnostic methods using the NGS, refer to the NGS instruction guide.
These tests can be used to diagnose the powertrain control module (PCM) (12A650), sensors and actuators of the 4R44E/4R55E transmission.
The following is a guide for using the On-Board Diagnostic (OBD) Quick Tests and the New Generation STAR (NGS) Tester.
Quick Test 1.0 - Visual Inspection
Perform the Visual Check and Vehicle Preparation procedures.
Inspect the following:
1. Air cleaner and inlet ducting.
2. All engine vacuum hoses for damage, such as leaks, cracks, blockage, proper routing, etc.
3. Powertrain control module (PCM) system wiring harnesses for proper connections, bent or broken pins, corrosion, loose wires, proper routing, etc.
4. Sensors, actuators and powertrain control module (PCM) for physical damage.
5. Engine coolant for proper level.
6. Transmission fluid for proper level and condition.
7. Any non-factory installed items wired into the transmission or PCM harnesses.
Perform all necessary servicing before continuing with Quick Tests.
Quick Test 2.0 - Set Up
Connect Rotunda New Generation STAR Tester 007-00500 or equivalent to Data Link Connector.
The following are steps to run OBD II procedures.
Vehicle and Tester Preparation
Prepare the vehicle as follows:
1. Transmission range selector lever in PARK.
2. Engine to operating temperature.
3. Apply parking brake.
4. Block wheels.
5. Turn off all electrical loads including A/C and defroster. (If A/C is ON, DTC P1460 will set.)
Prepare the NGS as follows:
1. Key OFF.
2. Verify that the proper program card is inserted in the NGS.
3. Connect J1962 16-way DCL cable adapter to the NGS.
4. Connect NGS DCL cable adapter securely into the vehicle's DCL connector.
5. Connect the NGS power supply cable to the vehicle battery power supply through cigarette lighter or at the battery with alligator clip adapter.
6. Key ON or start vehicle if necessary.
7. The NGS is now ready to communicate with the PCM.
Quick Test 3.0 - Key On, Engine Off (KOEO)
CAUTION: Do not replace parts based on a code, perform Pinpoint Tests first.
The key on engine off (KOEO) test provides "hard" diagnostic trouble codes (DTCs) present at the time of testing. Always service the "hard" DTCs first.
Performing KOEO
1. Perform visual inspection and vehicle preparation as required.
2. Select "Vehicle and Engine Selection" menu.
3. Select year, engine, model with the appropriate qualifier if needed, for example, transmission or 49 state/Cal.
4. Select "Diagnostic Data Link" menu.
5. Select "Diagnostic Test Mode" menu.
6. Select "KOEO On-Demand Self Test."
7. Follow operating instructions from the NGS menu screen.
8. Record all DTCs displayed.
Service non-transmission DTCs first as they can directly affect the operation of the transmission. Road test the vehicle and repeat Quick Test to verify the repair.
Quick Test 4.0 - Continuous Memory Codes
Continuous DTCs are concerns which were detected during normal vehicle operation. These codes are retained for 40 warm-up cycles.
The cause of some continuous DTCs may have been eliminated if KOEO and/or KOER DTCs were serviced. Always retest and service any DTCs that still remain.
If DTCs are present, go to the On-Board Diagnostic Trouble Code Description Chart for service information. Erase DTC, perform the Transmission Drive Cycle Test and repeat all Quick Test procedures after completing service on the DTCs.
If the Continuous test passes (P1111) and a concern is still present, refer to the Diagnosis by Symptom charts, OASIS and TSBs for concern diagnosis. Symptom Related Diagnostic Procedures
Performing Continuous DTC Tests
1. Select "Vehicle and Engine Selection" menu.
2. Select year, engine, model with the appropriate qualifier if needed, for example, transmission or 49 state/Cal.
3. Select "Diagnostic Data Unk" menu.
4. Select "Diagnostic Test Mode" menu.
5. Select "Retrieve Continuous Codes."
6. Follow operating instructions from the NGS menu screen.
7. Record all DTCs displayed.
8. Perform Transmission Drive Cycle Test.
9. Rerun Continuous DTC Test. If DTCs have returned, service as required. Road test and rerun all DTC test procedures.
Quick Test 5.0 - Key On, Engine Running (KOER)
This test provides "hard" DTCs only. Follow the menu screen instructions as they appear. If a DTC appears after the key on engine running (KOER) test, a malfunction is present. Refer to the DTC Code Chart for service information. Diagnostic Trouble Code Tests and Associated Procedures
Performing KOER
1. Perform visual inspection and vehicle preparation as required.
2. Select "Vehicle and Engine Selection" menu.
3. Select year, engine, model with the appropriate qualifier if needed, for example, transmission or 49 state/Cal.
4. Select "Diagnostic Data Link" menu.
5. Select "Diagnostic Test Mode" menu.
6. Select "KOER On-Demand Self Test."
7. Follow operating instructions from the NGS menu screen (example: turn key on, etc.) and perform brake on/off (BOO) and cycle the transmission control switch (TCS) on and off, if equipped, rotate steering wheel.
8. Record all DTCs displayed.
9. Service all non-transmission DTCs first as they can directly affect the operation of the transmission. Road test the vehicle and repeat Quick Test to verify the repair.