Diagnostic Instructions
DTC Descriptors
DTC P0741: Torque Converter Clutch (TCC) - Stuck Off
DTC P0742: Torque Converter Clutch (TCC) - Stuck On
Circuit/System Description
The torque converter clutch (TCC) pressure control (PC) solenoid is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The TCC PC solenoid is a normally low pressure control solenoid. The actuator
feed limit (AFL) valve supplies transmission fluid to the TCC PC solenoid. The TCC PC solenoid supplies transmission fluid to the TCC regulator valve in the lower valve body and the TCC control valve in the pump. When conditions are correct
to apply the converter clutch, the TCM will increase TCC PC current flow (duty cycle) thereby increasing pressure to move the TCC control valve into the apply position. When the TCC is fully applied, the engine is coupled directly to the transmission. TCC release
is accomplished by the TCM decreasing current flow, dropping the apply pressure allowing the TCC control valve to move to the release position.
Conditions for Running the DTC
| • | No DTCs P0716 or P0717 are active or have failed this key on. |
| • | No DTCs P0722 or P0723 are active or have failed this key on. |
| • | No DTCs P2762, P2763, or P2764 are active or have failed this key on. |
| • | Ignition voltage is between 8.6-18.0 volts. |
| • | The engine run time is greater than 5 seconds. |
| • | The transmission fluid temperature (TFT) is 20-130°C (68-266°F). |
| • | The accelerator pedal position signal is valid. |
| • | The calculated throttle position is between 8-100 percent. |
| • | The TCM must receive a valid torque signal from the ECM. |
| • | The engine torque is greater than 50 N·m (36 lb ft). |
| • | The following 6L80/6L90 gear ratios are achieved in the specified gear range while the TCC is commanded On: |
| - | The 2nd gear ratio is between 2.19-2.52. |
| - | The 3rd gear ratio is between 1.42-1.63. |
| - | The 4th gear ratio is between 1.07-1.23. |
| - | The 5th gear is between 0.79-0.91. |
| - | The 6th gear is between 0.62-0.71. |
| • | The following 6L50 gear ratios are achieved in the specified gear range while the TCC is commanded On: |
| - | The 2nd gear ratio is between 2.20-2.53. |
| - | The 3rd gear ratio is between 1.44-1.65. |
| - | The 4th gear ratio is between 1.07-1.23. |
| - | The 5th gear is between 0.79-0.91. |
| - | The 6th gear is between 0.62-0.72. |
| • | The TCC is commanded ON and PWM duty cycle is greater than 60 percent for 5 seconds. |
Conditions for Setting the DTC
P0741
The TCM detects TCC slip greater than 125 RPM for 5 seconds when the TCC is commanded ON. This must occur 4 times.
P0742
The TCM detects the TCC slip between -20 and +40 RPM for 4 seconds when the TCC is commanded OFF. This must occur 3 times.
Action Taken When the DTC Sets
| • | DTC P0741 is a Type B DTC. |
| • | DTC P0742 is a Type A DTC. |
| • | Inhibit high gear in Hot Mode. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DIC/DTC
| • | DTC P0741 is a Type B DTC. |
| • | DTC P0742 is a Type A DTC. |
Diagnostic Aids
When attempting to set transmission performance DTCs, it may be helpful to observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Description and Operation
Transmission General Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
Special Tools
DT-47825
Control Solenoid Test Plate
Circuit/System Verification
- Perform the
Transmission Fluid Check
.
- Operate the vehicle in drive with the calculated throttle position greater than 8 percent and ensure TCC is commanded ON and OFF a minimum of 5 times.
| ⇒ | If the DTC resets, go to Component Testing. |
Component Testing
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly Cleaning
in an attempt to clean or free up a potential sticking valve of dirt or debris.
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test
to test for a stuck open or stuck closed TCC PC solenoid valve inside of the control solenoid (w/body
and TCM) valve assembly.
| ⇒ | If a stuck open or closed valve is found, replace the control solenoid (w/body and TCM) valve assembly. |
- Inspect the lower control valve body for a stuck valve, debris or damage.
| ⇒ | If you found a valve body concern, repair or replace the lower control valve body as necessary. |
- Inspect the TCC control valve in the pump.
| ⇒ | If you found a TCC control valve concern, repair or replace the TCC control valve or pump as necessary. |
- Inspect the torque converter assembly for damage or discoloration.
| ⇒ | If you found a torque converter assembly concern, replace the torque converter assembly as necessary. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
| • | Control solenoid (w/body and TCM) valve assembly replacement: Refer to
Control Module References
for replacement, setup, and programming. |
