Circuit Description
The transmission control module (TCM) controls the torque converter clutch (TCC) solenoid valve pulse width modulation (PWM). The solenoid controls the hydraulic fluid for TCC apply and release. When the TCC is applied, the engine is coupled directly to
the transmission through the TCC. The TCC slip speed should be near 0.
If the TCM detects high torque converter slip when the TCC is commanded ON, then DTC P0741 sets. DTC P0741 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0741 Torque Converter Clutch (TCC) System - Stuck Off
Conditions for Running the DTC
| • | No MAF DTCs P0101, P0102 or P0103. |
| • | No MAP DTCs P0106, P0107 or P0108. |
| • | No TP DTCs P0121, P0122 or P0123. |
| • | No OSS DTCs P0722 or P0723. |
| • | No AT ISS DTCs P0716 or P0717. |
| • | No TCC stuck ON DTC P0742. |
| • | The engine run time is greater than 5 seconds. |
| • | The commanded gear is greater than 2. |
| • | The transmission fluid temperature is 20-133°C (68-271°F). |
| • | The TP angle is 2-90 percent. |
| • | The TCC PWM solenoid valve is commanded ON. |
| • | The TCC duty cycle is 65 percent or greater for 2 seconds. |
Conditions for Setting the DTC
TCC slip speed is 125 RPM or greater for 8 seconds 2 times during the same ignition cycle.
Refer to
Torque Converter Clutch Slip Speed
.
Action Taken When the DTC Sets
| • | The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The TCM commands maximum line pressure. |
| • | The TCM inhibits 4th gear if the transmission is in hot mode. |
| • | The TCM freezes transmission adaptive functions. |
| • | The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records and the TCM records the operating conditions when the Conditions for Setting the DTC are
met. The TCM stores this information as Failure Records. |
| • | The TCM stores DTC P0741 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | The TCM clears the DIC message when the condition no longer exists. |
| • | A scan tool can clear the MIL/DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM. |
Diagnostic Aids
| • | Inspect the transmission fluid level. |
| • | The transmission may be in hot mode. Inspect the transmission fluid lines to the radiator. The lines may be pinched, plugged or twisted. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step inspects the transmission fluid to ensure that it is at the proper level.
-
This step verifies that the TCC engages when commanded ON by the scan tool.
DTC P0741
Step
| Action
| Values
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Vehicle?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Vehicle
|
2
| Did you perform the Transmission Fluid Checking Procedure?
| --
| Go to
Step 3
| Go to
Transmission Fluid Check
|
3
|
- Install a scan tool.
- Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the TCM.
- Record the DTC Freeze Frame and Failure Records.
- Clear the DTC.
- Drive the vehicle at 72 km/h (45 mph).
- Using the scan tool, command the TCC PWM solenoid valve ON.
- Operate the vehicle under the following conditions:
| • | The transmission fluid temperature (TFT) is 20-130°C (68-266°F). |
| • | The engine torque is 50-1492 N·m (37-1100 lb ft). |
| • | Drive the vehicle in D4 with a throttle position (TP) angle of 2-90 %. |
| • | Ensure that the TCC applies for more than 5 seconds. |
- Monitor the TCC slip speed.
During TCC application, is the slip speed within the specified parameters?
| -20 to +100 RPM
| Go to Diagnostic Aids
| Go to
Step 4
|
4
|
- During TCC apply, if NO change in TCC slip speed, inspect for the following conditions:
| • | The TCC control valve is stuck OFF due to sediment or binding. |
| • | The TCC regulator valve is stuck OFF due to sediment or binding. |
| • | The TCC feed valve is stuck OFF due to sediment or binding. |
| • | The TCC enable valve is stuck OFF due to sediment or binding. |
- During TCC apply, if SOME change in TCC slip speed, inspect for the following conditions:
| • | The TCC PWM oil pressure screen is clogged. |
| • | The TCC PWM solenoid valve O-ring is leaking or cut. |
| • | The turbine shaft seal, case cover to drive sprocket seal and drive sprocket support are worn. |
- Repair any of the above items as necessary.
- If no problems found in previous conditions, replace the T/C viscous clutch.
Did you complete the repair?
| --
| Go to
Step 5
| --
|
5
| Perform the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Operate the vehicle under the following conditions:
| • | The TFT is 20-130°C (68-266°F). |
| • | The engine torque is 50-1492 N·m (37-1100 lb ft). |
| • | Drive the vehicle in D4 with a TP angle of 10-50%. |
| • | Ensure that the TCC applies and the slip speed is -20 to +55 RPM for 4 seconds. |
- Select Specific DTC.
- Enter DTC P0741.
Has the test run and passed?
| --
| Go to
Step 6
| Go to
Step 2
|
6
| With the scan tool, observe the stored information, capture info. and DTC info.
Does the scan tool display any DTCs that you have not diagnosed?
| --
| Go to
Diagnostic Trouble Code (DTC) List - Vehicle
| System OK
|
