Automatic Transmission Diagnosis

AUTOMATIC TRANSMISSION DIAGNOSIS

Diagnosing electronically controlled automatic transmissions is simplified by using the following procedures. It is important to remember that there is a definite procedure to follow. Do not take shortcuts or assume that critical checks or adjustments have already been made. Follow the procedures as written to avoid missing critical components or steps.

On-Board Diagnostics With IDS or Equivalent Tester

Perform the Quick Tests first using the integrated diagnostic system (IDS) or equivalent tester.
For information on diagnostic testing features using the IDS or equivalent tester, see IDS or equivalent tester manual and - On - Board Diagnostic Tests.

5R44E/5R55E Output State Control (OSC) Mode

Output state control (OSC) allows the technician to take control of certain parameters to function the transmission. For example, OSC allows the technician to shift the transmission only when commanding a gear change. If the technician commands 1st gear in OSC, the transmission will remain in 1st gear until the technician commands the next gear. For another example, the technician can command a shift solenoid to turn on or off when performing an electrical circuit check. OSC has two modes of operation for transmission, the bench mode and the drive mode. Each mode/parameter has a unique set of vehicle operating requirements that the technician is required to meet before being allowed to operate OSC.

NOTE:To operate OSC the digital transmission range (TR) sensor and the vehicle speed sensor (VSS) must be operational. No diagnostic trouble codes (DTCs) related to the digital TR sensor or the VSS can be present.

- The vehicle requirements must be met when sending the OSC value. See vehicle requirements for each individual test.
- If the vehicle requirements are not met when sending the OSC value, an error message appears. When the error message is received, OSC is aborted and must be restarted.
- If after sending an OSC value, and the vehicle requirements are no longer met, the PCM will cancel the OSC value and no error message appears.
- The OSC value [XXX] may be sent anytime to cancel OSC.

Output State Control (OSC) Procedures:

- Perform visual inspection and vehicle preparation as required.
- Select Vehicle and Engine Selection menu.
- Select appropriate vehicle and engine.
- Select Diagnostic Data Link.
- Select Powertrain Control Module.
- Select Diagnostic Test Mode.
- Select KOEO On-Demand Self Test and KOER On-Demand Self Tests.
- Perform test and record DTCs.
- Repair all non-transmission DTCs.
- Repair all VSS and digital TR sensor DTCs.
- Make sure that VSS/digital TR sensors are functional.
- Select Active Command Modes.
- Select Trans-Bench Mode or Trans-Drive Mode.

5R44E/5R55E OSC Transmission Bench Modes

The following transmission bench modes may be used or required during diagnostics.

SSA, SSB, SSC, SSD and TCC in Bench Mode:

The bench mode allows the technician to perform electrical circuit checks on the following components:

- SSA - Activates SSA OFF or ON.
- SSB - Activates SSB OFF or ON.
- SSC - Activates SSC OFF or ON.
- SSD - Activates SSD OFF or ON.
- TCC - Activates TCC OFF or ON.
OSC SSA, SSB, SSC, SSD, TCC bench mode operates only when:

- VSS and digital TR sensor are operational.
- No VSS and digital TR sensor DTCs.
- Transmission range selector lever in P.
- Key ON.
- Key OFF.
OSC Command Values

- [OFF] - turns solenoid OFF.
- [ON] - turns solenoid ON.
- [XXX] - cancels OSC value sent.
- [SEND] - sends the values to PCM.
Bench mode procedure for SSA, SSB, SSC, SSD, and TCC
Follow operating instructions from the IDS or equivalent tester menu screen:

- Select Output State Control.
- Select Trans - Bench Mode.
- Select PIDs to be monitored.
- Monitor all selected PIDs during test.
- Select parameters - SSA, SSB, SSC, SSD, or TCC.
- Select ON to turn solenoid ON.
- Press SEND to send command ON.
- Select OFF to turn solenoid OFF.
- Press SEND to send command OFF.
- Select XXX to cancel at any time.
- Press SEND.

5R44E/5R55E Electronic Pressure Control (EPC) in Bench Mode

The bench mode is also used to test the functionality of the transmission's EPC. During bench mode, the EPC solenoid can ramp in increments of 15 PSI from zero to 90 PSI and 90 to zero PSI.
The OSC functions for the parameter EPC allow the technician to choose the following operations.

- EPC - Activates EPC to selected values.
- [00] - sets EPC pressure to 00 PSI.
- [15] - sets EPC pressure to 15 PSI.
- [30] - sets EPC pressure to 30 PSI.
- [45] - sets EPC pressure to 45 PSI.
- [60] - sets EPC pressure to 60 PSI.
- [75] - sets EPC pressure to 75 PSI.
- [90] - sets EPC pressure to 90 PSI.
OSC EPC bench mode operates ONLY when:

- VSS and digital TR sensor are operational.
- No VSS and digital TR sensor DTCs.
- Transmission range selector lever in P.
- Pressure gauge installed.
- Key ON.
- Engine ON.
- Engine rpm at 1500.
OSC Command Values

- [00] - sets EPC pressure to 00 PSI.
- [15] - sets EPC pressure to 15 PSI.
- [30] - sets EPC pressure to 30 PSI.
- [45] - sets EPC pressure to 45 PSI.
- [60] - sets EPC pressure to 60 PSI.
- [75] - sets EPC pressure to 75 PSI.
- [90] - sets EPC pressure to 90 PSI.
- [OFF] - turns solenoid off.
- [ON] - turns solenoid on.
- [XXX] - cancels OSC value sent.
- [SEND] - sends the values to PCM.

5R44E/5R55E Bench Mode Procedure for EPC

Following operating instructions from the IDS or equivalent tester menu screen.

- Select Output State Control.
- Select Trans - Bench Mode.
- Select PIDs to be monitored.
- Monitor all selected PIDs during test.
- Select Parameters - EPC.
- Select Value 0-90 psi.
- Press SEND to send command.
- Select XXX to cancel at any time.

5R44E/5R55E OSC Transmission Drive Modes

The drive mode allows control of three transmission parameters. Each mode/parameter has a unique set of vehicle operating requirements that the technician is required to meet before being allowed to operate OSC. The recommended procedure, when using the drive mode, is to control one parameter at a time.
The drive mode allows the technician to perform the following functions on the transmission:

- GR_CM - allows upshifts or downshifts.
- TCC - engages or disengages the torque converter clutch.
- EPC - increases/decreases EPC pressure.

5R44E/5R55E GR_CM in Drive Mode

This OSC function is used to test the transmission shift functions.
The OSC functions for the GR_CM parameter allows the technician to choose the following options:

- [1] - PCM selects 1st gear.
- [2] - PCM selects 2nd gear.
- [3] - PCM selects 3rd gear.
- [4] - PCM selects 4th gear.
- [5] - PCM selects 5th gear.
OSC GR_CM Mode Operates ONLY when:

- VSS and digital TR sensor are operational.
- No VSS and digital TR sensor DTCs.
- Engine ON.
- TCC OFF.
- Transmission range selector lever on O/D.
- Vehicle speed is greater than 2 mph.
OSC Command Values

- [1] - PCM selects 1st gear.
- [2] - PCM selects 2nd gear.
- [3] - PCM selects 3rd gear.
- [4] - PCM selects 4th gear.
- [5] - PCM selects 5th gear.
- [OFF] - turns solenoid off.
- [ON] - turns solenoid on.
- [XXX] - cancels OSC value sent.
- [SEND] - sends the values to PCM.

5R44E/5RR5E Drive Mode Procedures for GR_CM

Following operating instructions from the IDS or equivalent tester menu screen.

- Select Output State Control.
- Select Trans - Drive Mode.
- Select PIDs to be monitored.
- Monitor all selected PIDs during test.
- Select Parameters - GR_CM.
- Select Value 1-5.
- Press SEND to send command.
- Re-Select Value 1-5.
- Press SEND to send command.
- Select XXX to cancel at any time.

5R44E/5R55E TCC in Drive Mode:

This OSC function is used to test whether the torque converter clutch is engaging and disengaging correctly.
The OSC functions for the TCC parameter allows the technician to choose the following:

- TCC - activates TCC OFF and ON.
- [ON] - turns TCC solenoid ON.
- [OFF] - turns TCC solenoid OFF.
OSC TCC OFF drive mode operates only when:

- VSS and digital TR sensors are operational.
- No VSS and digital TR sensor DTCs present.
- Engine ON.
- Transmission range selector lever in O/D.
- Vehicle speed is greater than 3 km/h (2 mph).
OSC TCC ON drive mode operates only when:

- VSS and digital TR sensors are operational.
- No VSS and digital TR sensor DTCs present.
- Engine on.
- Transmission range selector lever in O/D.
- Vehicle speed is greater than 3 km/h (2 mph).
- Transmission in 2nd gear or higher.
- TFT is between 16°C and 135°C (60°F and 275°F).
- Brake not applied OFF below 32 km/h (20 mph).
- Not an excessive load on engine (engine lugging).
OSC Command Values

- [OFF] - turns TCC OFF.
- [ON] - turns TCC ON.
- [XXX] - cancels OSC value sent.
- [SEND] - sends the values to PCM.

5R44E/5R55E Drive Mode Procedures for TCC

Follow operating instructions from the IDS or equivalent tester menu screen.

- Select Output State Control.
- Select Trans - Drive Mode.
- Select PIDs to be monitored.
- Monitor all selected PIDs during test.
- Select Parameters - TCC.
- Select ON to turn solenoid ON.
- Press SEND to send command ON.
- Select OFF to turn solenoid OFF.
- Press SEND to send command OFF.
- Press XXX to cancel at any time.

5R44E/5R55E EPC in Drive Mode

This OSC function is used to increase the EPC pressure while testing the transmission shift functions. This OSC function can only increase the EPC pressure greater than what the PCM normally commands. If an OSC value, such as 75 or 90 PSI is sent, the upshifts and downshifts should exhibit a harsher shift. Harsher shifts would indicate that the EPC pressure control works at higher pressures. The best test for the EPC is to use the bench mode and a hydraulic pressure gauge. Using EPC in the bench mode confirms that the EPC works at both the higher and lower pressures.
The OSC functions for the parameter EPC allow the technician to choose the following options:

- EPC - activates EPC to selected

- [00] - sets EPC pressure to 00 PSI.
- [15] - sets EPC pressure to 15 PSI.
- [30] - sets EPC pressure to 30 PSI.
- [45] - sets EPC pressure to 45 PSI.
- [60] - sets EPC pressure to 60 PSI.
- [75] - sets EPC pressure to 75 PSI.
- [90] - sets EPC pressure to 90 PSI.
OSC EPC drive mode operates only when:

- VSS and digital TR sensor are operational.
- No VSS and digital TR sensor DTCs.
- Transmission range selector lever in O/D.
- Pressure gauge installed.
- Key ON.
- Engine ON.
- Vehicle speed greater than 2 mph.
- OSC value for EPC must be greater than what the PCM commands (see EPC PID).
OSC Command Values

- [00] - sets EPC pressure to 00 PSI.
- [15] - sets EPC pressure to 15 PSI.
- [30] - sets EPC pressure to 30 PSI.
- [45] - sets EPC pressure to 45 PSI.
- [60] - sets EPC pressure to 60 PSI.
- [75] - sets EPC pressure to 75 PSI.
- [90] - sets EPC pressure to 90 PSI.
- [OFF] - turns solenoid off.
- [ON] - turns solenoid on.
- [XXX] - cancels OSC value sent.
- [SEND] - sends the values to PCM.
Drive Mode Procedure for EPC.
Follow operating instructions from the IDS or equivalent tester menu screen.

- Select Output State Control.
- Select Trans - Drive Mode.
- Select PIDs to be monitored.
- Monitor all selected PIDs during test.
- Select Parameters - EPC.
- Select Value 0-90 psi.
- Press SEND to send command.
- Re-Select Value 0-90 psi.
- Press SEND to send command.
- Select XXX to cancel at any time.

5R44E/5R55E Using Output State Control (OSC) and Accessing PIDs

To confirm that the OSC value was sent by the IDS or equivalent tester and the PCM has accepted the OSC substitution, a corresponding PID for each OSC parameter must be monitored. Additional PIDs should be monitored to help the technician adequately diagnose the transmission.
The following is a list of OSC parameters and their corresponding PID:





To confirm that the OSC substitution occurred, send the OSC value and monitor the corresponding PID value. If no error message was received and the value of the corresponding PID remains the same as the value sent from OSC, then the OSC substitution was successful.

Transmission Drive Cycle Test

NOTE:Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.
NOTE:The Transmission Drive Cycle Test must be followed exactly. Malfunctions must occur four times consecutively for shift error DTC to be set, and five times consecutively for continuous torque converter clutch code to set.
NOTE:When performing the Transmission Drive Cycle Test, see the Solenoid Application Chart for proper solenoid operation.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 overdrive, moderately accelerate from stop to 80 km/h (50 mph). This allows the transmission to shift into fifth gear. Hold speed and throttle open steady for a minimum of 15 seconds.

5. With transmission in 5th 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 5 seconds.

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 DTCs.

- If the DTCs are still present, refer to the DTC Chart. Diagnostic Trouble Code Descriptions Repair all non-transmission DTCs first as they can directly affect the operation of the transmission. Repeat the Quick Test and the Road Test to verify the correction. Erase the DTCs, carry out the Drive Cycle Test and repeat the Quick Test after completing repair on the DTC.
- If the continuous test passes and a concern is still present, refer to Automatic Transmission Special Testing Procedure.

After On-Board Diagnostic

NOTE:The vehicle wiring harness, PCM and non-transmission sensors may affect transmission operations. Repair these concerns first.After the on-board diagnostic procedures are completed, repair all DTCs.
Begin with non-transmission related DTCs, then repair any transmission related DTCs. See the On-Board Diagnostic Trouble Code Chart for information on condition and symptoms. This chart will be helpful in referring to the proper manual(s) and aids in diagnosing internal transmission concerns and external non-transmission inputs. The tests are used in diagnosing transmission electrical concerns. Make sure that the vehicle wiring harness and the PCM are diagnosed as well. See - Diagnostic Trouble Code (DTC) Index - Powertrain Control Module (PCM).

Before Performing Tests

NOTE:Prior to entering test procedures, 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. See - On - Board Diagnostic Tests.
NOTE:If a concern still exists after electrical diagnosis has been performed, see Diagnosis by Symptom. See - Symptom Troubleshooting Chart - Automatic Transmission.If DTCs appear while performing the on-board diagnostics, see the Diagnostic Trouble Code Index for the appropriate repair procedure. See - DTC Index - Automatic Transmission.

Transmission Connector Layout
Transmission Vehicle Harness Connector










Digital Transmission Range (TR) Sensor Vehicle Harness Connector










Output Shaft Speed (OSS) Sensor Connector





Control Valve Body Wire Harness Diagram










Diagnostic Tests

Any time an electrical connector or solenoid body is disconnected, inspect the connector for terminal condition, corrosion and contamination. Also inspect the connector seal for damage. Clean, repair or replace as required.

Shift Solenoid Pre-Diagnosis

Use the following shift solenoid operation information when performing test.
Digital Transmission Range (TR) Sensor Diagnosis Chart





Will read Drive if O/D is canceled.
1 TR_V is the voltage at the PCM pin 64 (TR3A Circuit) to signal return.
2 In Between reading could be caused by a shift cable or digital TR sensor misaligned or a digital TR sensor circuit failure of TR1, TR2, TR3A, or TR4.
3 TR_D: 1=Open Digital TR switch, 0=Closed Digital TR switch.
4 Breakout Box Readings: Taken from PCM signal pins for TR1, TR2, TR3A, TR4 to signal return.

- Voltages for TR1, TR2, TR4: 0=0.0 volts (circuit shorted to ground).
- 1=9.0 - 14.0 volts (open circuit).
- Voltage for TR3A: 0=0.0 volts (circuit shorted to ground).
- 1=1.3 - 1.8 volts (open circuit).
- 0.0 volts=Closed Digital TR switch.
- 1.3 - 1.8 volts=Open Digital TR switch.
1 TR4, TR3A, TR2, and TR1 are all closed in PARK (shorted to signal return), so PARK is a good position to check for intermittent open circuits.
2 TR4, TR3A, TR2, and TR1 are all open in OVERDRIVE, so OVERDRIVE is a good position to check for shorts to ground. To determine the shorted components while observing TR_D, unplug the TR and see if the short goes away.
3 If the short is still present, unplug the transmission harness and see if the short goes away.
4 It the short is still present, then the short is in the PCM or vehicle harness. Remove the suspect circuit(s) wire from the PCM vehicle harness.
5 If the short is still present, then the PCM has an internal failure, otherwise the failure is in the vehicle harness.

Shift Solenoid Failure Mode Chart Always Off

Failed ON due to PCM and/or vehicle wiring concerns, solenoid electrically, mechanically or hydraulically stuck OFF.





When a manual pull-in occurs above a calibrated speed, the transmission will downshift from the higher gear until the vehicle speed drops below this calibrated speed.









When a manual pull-in occurs above a calibrated speed, the transmission will downshift from the higher gear until the vehicle speed drops below this calibrated speed.
Shift Solenoid Failure Mode Chart Always On

Failed OFF due to PCM and/or vehicle wiring concerns, solenoid electrically, mechanically or hydraulically stuck ON.





When a manual pull-in occurs above a calibrated speed, the transmission will downshift from the higher gear until the vehicle speed drops below this calibrated speed.









When a manual pull-in occurs above a calibrated speed, the transmission will downshift from the higher gear until the vehicle speed drops below this calibrated speed.
Solenoid Application Chart





PCM Controlled

On time calibration dependent

Shift Solenoid Failure Mode Chart Always On

Failed OFF due to PCM and/or vehicle wiring concerns, solenoid electrically, mechanically or hydraulically stuck ON.

















Shift Solenoid Failure Mode Chart Always Off

Failed ON due to PCM and/or vehicle wiring concerns, solenoid electrically, mechanically or hydraulically stuck OFF.









During Downshift Only

During Upshift Only