Displaying & Reading Trouble Codes

Perform On-Board Diagnostics

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.

After a road test, with the vehicle warm and before disturbing any connectors, perform the Quick Test using New Generation STAR (NGS) Tester 007-00500 or equivalent.

Diagnostics

Diagnosing 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 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.

The quick tests are in the . These tests can be used to diagnose the powertrain control module (PCM)( 1 2A650), sensors and actuators of the 4R70W transmission.

The following is 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:

Quick Test 1.0 - Visual Inspection

Perform the Visual Check and Vehicle Preparation procedures.

Inspect the following:

- Air cleaner and inlet ducts
- All engine vacuum hoses for damage such as leaks, cracks, blockage, proper routing, etc.
- PCM system wiring harnesses for proper connections, bent or broken pins, corrosion, loose wires, proper routing, etc.
- Powertrain control module, sensors and actuators for physical damage
- Engine coolant for proper level
- Transmission fluid for proper level and condition
- Any non4actory installed items wired into the transmission or PCM harnesses

Perform all necessary service before continuing with Quick Tests.

Quick Test 2.0 - Set Up

Connect Rotunda New Generation STAR (NGS) Tester 007-00500 or equivalent to data link connector (DLC).

Vehicle and Tester Preparation

Prepare to run OBD II procedures.

- Transmission range selector lever in PARK
- Engine at operating temperature
- Apply parking brake
- Block wheels
- Turn off all electrical loads including A/C and defroster. (If A/C is on, DTC P1460 will set.)

Prepare the NGS as follows:

- Turn ignition switch (11572) to the OFF position.
- Verify that the proper program card is inserted in the NGS.
- Connect J1962/16 way DCL cable adapter to the NGS.
- Connect NGS DCL cable adapter securely into the vehicle's data link connector.
- Connect the NGS power supply cable to the vehicle battery power supply through cigar lighter or at the battery with alligator clip adapter.
- Turn the ignition switch to the RUN position, or start vehicle if necessary.

The NGS is 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.

Some special considerations for Key On, Engine Off Quick Test include the following:

- The key on, engine off (KOEO) test provides diagnostic trouble codes (DTCs) present at the time of testing.
- Always service DTCs first.

Performing KOEO

- Perform visual inspection and vehicle preparation as required.
- Select "Vehicle and Engine Selection" menu.
- Select year, engine, model with the appropriate qualifier if needed (for example, transmission or 49 state/Cal).
- Select "Diagnostic Data Link" menu.
- Select "Diagnostic Test Mode" menu.
- Select "KOEO On-Demand Self-Test".
- Follow operating instructions from the NGS menu screen.
- 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 results.

Quick Test 4.0- Continuous Memory Codes

Continuous DTCs are concerns which were detected during normal vehicle operation. These DTCs 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 Chart, OASIS and TSBs for concern diagnosis.

Performing Continuous DTC Tests

- Select "Vehicle and Engine Selection" menu.
- Select year, engine, model with the appropriate qualifier if needed (for example, transmission or 49 state/Cal).
- Select "Diagnostic Data Link" menu.
- Select "Diagnostic Test Mode" menu.
- Select "Retrieve Continuous Codes" menu.
- Follow operating instructions from the NGS menu screen.
- Record all DTCs displayed.
- Perform Transmission Drive Cycle Test.
- 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 On-Board Diagnostic Trouble Code Description Chart for service information. Diagnostic Trouble Code Tests and Associated Procedures

Performing KOER

- Perform visual inspection and vehicle preparation as required.
- Select "Vehicle and Engine Selection" menu.
- Select year, engine, model with the appropriate qualifier if needed, for example, transmission or 49 state/Cal.
- Select "Diagnostic Data Link" menu.
- Select "Diagnostic Test Mode" menu.
- Select "KOER On-Demand Self-Test".
- Follow operating instructions from the NGS menu screen (example: turn key on, etc..). Perform brake on/oft and cycle the transmission control switch (TCS) on and off, if equipped.
- Record all DTCs displayed.
- 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.

Special Test Modes

- Diagnostic Test Modes
- PCM Reset Mode

Diagnostic Test Mode

The diagnostic test mode (DTM) aids in servicing output actuators associated with the OBD II system. It allows the technician to energize and de-energize most of the system output actuators on command.

Performing Diagnostic Test Mode

NOTE: You must enter DTM with ignition switch in RUN and the engine off.

- Perform visual inspection and vehicle preparation as required.
- Select "Vehicle and Engine Selection" menu.
- Select year, engine, model with the appropriate qualifier if needed (for example, transmission or 49 state/Cal).
- Select "Diagnostic Data Link" menu.
- Select "Diagnostic Test Mode" menu.
- Enter "Active Tests".
- Enter "Output Control".
- Follow operating instructions from the NGS menu screen.

PCM Reset Mode

The PCM reset mode permits the NGS to command the PCM to clear all DTCs. When resetting the PCM, a DTC P1000 will be set in the PCM until all OBD II system or components have been monitored during OBD II Drive Cycle.

A PCM reset:

- Clears the DTCs
- Clears the freeze frame data
- Clears the oxygen sensor test data
- Resets the status of the OBD II system monitors
- Sets the DTCP1OOO

Performing PCM Reset

- Perform visual inspection and vehicle preparation as required.
- Select "Vehicle and Engine Selection" menu.
- Select year, engine, model with the appropriate qualifier if needed, for example, transmission or 49 state/Cal.
- Select "Generic OBD II Functions" menu.
- Select "Clearing ALL Codes".
- Follow operating instructions from the NGS menu screen.
- Perform OBD II Drive Cycle-Clear DTC P1000.

Clearing DTC P1000

In some localities it may become a legal requirement to pass an Inspection/Maintenance (I/M) test of the OBD II System. If the vehicle OBD II system or its battery has just been serviced, the PCM system is reset to a "not ready for I/M testing" condition. To prepare the vehicle for this test and to clear the DTC P1000, the OBD II Drive Cycle must be performed.

OBD II Drive Cycle

NOTE: The following steps must be run in the order shown. If steps 2, 3 or 4 are interrupted, repeat the step before proceeding. Any safe driving mode is acceptable between steps.

Always drive vehicle in a safe manner according to traffic conditions and obey all traffic laws.

1. Start engine and drive vehicle in typical city stop and go traffic for at least 10 minutes after engine has reached normal operating temperature.

2. Idle vehicle for at least 45 seconds, then accelerate at part throttle to about 72 km/h (45 mph).

3. Cruise and maintain a speed in the range of 48 to 64 km/h (30 to 40 mph) on a level road with throttle held steady for at least one minute.

4. Cruise and maintain a speed in the range of 64 to 105 km/h (40 to 65 mph) on a level road with throttle held steady for at least one minute and 20 seconds.

5. OBD II Drive Cycle has been completed.

Other NGS Features

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 PIDs
- Oxygen Sensor Monitor Mode, used to monitor the heated oxygen (HO2S) sensor

Transmission Drive Cycle Test

After performing the Quick Test, use the Transmission Drive Cycle Test for checking transmission continuous codes.

NOTE: The Transmission Drive Cycle Test must be followed exactly. A malfunction must occur four times consecutively for DTCs P0781, P0782, P0783, P1731, P1732, P1733 to be set, and five times consecutively for continuous DTC P0741.

1. Record and then erase Quick Test DTCs.

2. Warm engine to normal operating temperature.

3. Make sure transmission fluid level is correct.

4. With transmission In OVERDRIVE, moderately accelerate from stop to 80 km/h (50 mph). This allows the transmission to shift into fourth gear. Hold speed and throttle open steady for a minimum of 15 seconds.

5. With transmission in OVERDRIVE, press TCS (TCIL should illuminate) and moderately accelerate from stop to 64 km/h (40 mph). This allows the transmission to shift into third gear. Hold speed and throttle open steady for a minimum of 15 seconds (30 seconds above 4000 ft).

6. Press TCS (TCIL should turn off) and accelerate from 64km/h (40mph) to 80km/h (50mph). This allows transmission to shift into fourth gear. Hold speed and throttle position steady for a minimum of 15 seconds.

7. With transmission in fourth gear and maintaining steady speed and throttle opening, lightly apply and release brake to operate stoplamps. Then hold speed and throttle steady for a minimum of five seconds.

8. Brake to a stop and remain stopped for a minimum of 20 seconds.

9. Repeat Steps 4 through 8 at least five times.

10. Perform Quick Test and record continuous DTCs.

After On-Board Diagnostic

NOTE: The vehicle wiring harness, powertrain control module (PCM)(12A650) and non-transmission sensors may affect transmission operations. Service these concerns first.

NOTE: If a concern still exists after electrical diagnosis has been performed, refer to Diagnosis by Symptom in this section. Symptom Related Diagnostic Procedures

After the on-board diagnostic procedures are completed, service all DTCs.

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. Diagnostic Trouble Code Tests and Associated Procedures This chart will be helpful in referring to the proper manual(s) and to aid in diagnosing internal transmission concerns and external non4ransmission inputs. The pinpoint tests are used in diagnosing transmission electrical concerns. Make sure that the vehicle wiring harness and the powertrain control module are diagnosed as well. Computers and Control Systems will aid in diagnosing non-transmission electronic components.