Description of On-Board Diagnostics
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 OO7-OO50O 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 Teat 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 Teat 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.
Special Test Modes
The following Special Test Modes may be used or required during diagnostics.
Output Test Mode
The diagnostic test mode aids is servicing output actuators associated with the PCM system. It allows the technician to energize and deenergize most of the system output actuators on command.
Performing Output Test Mode
Enter Output Test Mode with ignition key ON and the engine OFF.
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. Enter "Active Tests."
7. Enter "Output Control."
8. Follow operating instructions from the NOS menu screen.
PCM Reset Mode
The PCM reset mode provides a means for the NGS to command the powertrain control module (PCM) to clear all DTCs. When resetting the PCM, a DTC P1000 will be set in the PCM until all OBDII system or components have been monitored during the OBDII Drive Cycle. When a PCM reset is performed the following occurs:
a. DTCs cleared.
b. Freeze Frame Data cleared.
c. Oxygen sensor Test Data cleared.
d. Status of the OBDII System Monitors reset.
e. DTCP1OOO set.
Performing PCM Reset
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 "Generic OBDII Functions" menu.
5. Select "Clearing ALL Codes."
6. Follow operating instructions from the NGS menu screen.
7. Perform OBDII 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 OBDII system. If the vehicle's powertrain system or its battery has just been serviced, the OBDII system is reset to a not ready for I/M testing condition. To prepare the vehicle for the test and to clear the DTC No. P1000, an OBDII Drive Cycle must be performed.
OBDII Drive Cycle
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 it has reached normal operating temperature.
2. Idle vehicle for at least 45 seconds, then accelerate at part throttle to near 72 km/h (45 mph).
3. Cruise and maintain a select speed in the range of 48-64 km/h (30 to 40 mph) on a level road with throttle held steady for at least one minute.
4. Drive to accumulate at least four minutes in the range of 32-72 km/h (20 to 45 mph). If stop-and-go conditions occur, the accumulated time must be within the 32-72 km/h (20 to 45 mph) range. No wide open throttle (WOT) conditions should be encountered.
5. Decelerate and idle for at least 10 seconds.
6. Accelerate to approach 88 km/h (55 mph) at 1/2 throttle (elapsed time is about 10 seconds).
7. Cruise and maintain select speed in the range of 64-104 km/h (40 to 65 mph) on a level road with throttle held steady for at least one minute and 20 seconds.
8. OBDII Drive Cycle has been completed.
Other NGS Features
For further information on other diagnostic testing features using the NGS or generic scan tool, refer to the tool's instruction manual. Other diagnostic methods include the following:
a. Parameter Identification (PID) Access Mode, used to monitor sensor and actuators.
b. Freeze Frame Data Access Mode, used to view emissions related data values from specific PIDs.
c. Oxygen Sensor Monitor Mode, used to monitor the 02 sensor.
Transmission Drive Cycle Test
NOTE: The Transmission Drive Cycle Test must be followed exactly. Malfunctions must occur four times consecutively for codes P0731, P0732, P0733 and P0734 to be set, and five times consecutively for continuous codes P0741 and P0743.
After performing the Quick Test, use the Transmission Drive Cycle Test for checking continuous codes.
1. Record and then erase Quick Test codes.
2. Warm engine to normal operating temperature.
3. Make sure transmission fluid level is correct.
4. With transmission in (D), moderately accelerate from stop to 80 km/h (50 mph). This allows the transmission to shift into fourth gear. Hold speed and throttle opening steady for a minimum of 15 seconds.
5. With transmission in fourth gear and maintaining steady speed and throttle opening, lightly apply and release brake pedal (2455) (to operate stoplamps). Then hold speed and throttle steady for an additional five seconds (minimum).
6. Brake to a stop and remain stopped for a minimum of 20 seconds.
7. Repeat Steps 4 through 6 at least five times.
8. Perform Quick Test and record continuous codes.
If DTCs are present, go to the On-Board Diagnostic Trouble Code Description Chart in this section for service information. Service all non-transmission DTCs first as they can directly affect the operation of the transmission. Repeat the Quick Test and Road Test to verify the correction. Erase DTCs, perform Drive Cycle and repeat the Quick Test after completing service on the DTCs.
If the continuous test passes and a concern is still present, refer to the Diagnosis by Symptom charts, OASIS and TSBs for concern diagnostics. Symptom Related Diagnostic Procedures