Circuit Description
The torque converter clutch (TCC) power transfer capacity is controlled by the balance of automatic transmission fluid (ATF) supply, and discharges to and from the torque converter. As hydraulic pressure in the internal pressure side increases, the power transfer capacity of the TCC increases. The direction of hydraulic pressure supply is switched by TCC solenoid valve and the lock-up shift valve. When the powertrain control module (PCM) commands the TCC enable solenoid valve ON, 12 V, the ATF is supplied from the internal pressure side. When the PCM commands the TCC enable solenoid valve OFF, 0 V, the ATF is supplied from the back pressure side. The balance of internal pressure and back pressure is controlled by the combination of the clutch pressure control (PC) solenoid valve, the lock-up control valve and the lock-up timing valve. The TCC PC solenoid valve maximizes the TCC power transfer capacity when the PCM command is ON, 100%, and it minimizes the TCC power transfer capacity when the PCM command is OFF, 0%.
If the proportion of engine speed and transmission input speed is not approximately 1, while the PCM is commanding the TCC enable solenoid valve and the TCC PC solenoid valve ON, 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 ECT DTCs P0116, P0117, P0118. |
| • | No TP DTCs P0122, P0123, P0222, or P0223. |
| • | No VSS DTCs P0501, P0502, or P0503. |
| • | No TR Switch DTCs P0705, or P0706. |
| • | No AT ISS DTCs P0716, P0717, or P0718. |
| • | No Clutch PC Performance DTCs P0746, P0747, P0776, or P0777. |
| • | No SS Valve Performance DTCs P0751, P0752, P0756, P0761, P0757, or P0762. |
| • | No Incorrect Shift Pattern DTC P0780. |
| • | No Clutch PC Solenoid Electrical DTCs P0962, or P0963. |
| • | No Clutch PC Solenoid 2 DTCs P0966, or P0967. |
| • | No SS 1 DTCs P0973 or P0974. |
| • | No SS 2 DTCs P0976 or P0977. |
| • | No SS 3 DTCs P0979 or P0980. |
| • | No TAC DTCs P2101, P2108, P2111, P2112, or P2553. |
| • | No APP DTC P2122, P2123, P2127, P2128, P2135, or P2138. |
| • | No Minimum Idle Position DTC P2176. |
| • | No TCC PC Solenoid DTCs P2763 or P2764. |
| • | No TCC Enable Solenoid DTCs P2769 or P2770. |
| • | No TAC Communication DTC U0107. |
| • | The system voltage is 11 volts or greater. |
| • | The engine coolant temperature (ECT) is 70-100°C (158-212°F). |
| • | The commanded gear is 5th. |
| • | The TCC is enabled. |
| • | The vehicle is at a steady speed of 80 km/h (50 mph)-120 km/h (75 mph) for greater than 20 seconds. |
Conditions for Setting the DTC
The TCC slip ratio to the APP angle is as follows:
| • | If the throttle angle is 18.4%, the Torque Converter Efficiency must be less than 93 or greater than 102. |
| • | If the throttle angle is 15.6%, the Torque Converter Efficiency must be less than 95 or greater than 102. |
| • | If the throttle angle is 13.2%, the Torque Converter Efficiency must be less than 96 or greater than 102. |
| • | If the throttle angle is 6.2%, the Torque Converter Efficiency must be less than 98 or greater than 102. |
| • | If the throttle angle is 3.1%, the Torque Converter Efficiency must be less than 98 or greater than 102. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
| • | The PCM stores DTC P0741 in PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Inspect for a mechanical failure of the TCC. |
| • | Inspect for a mechanical failure of the TCC PC solenoid valve. |
| • | Inspect for a mechanical failure of the TCC enable solenoid valve. |
| • | Inspect for a stuck lock-up shift valve. |
| • | Inspect for a stuck lock-up control valve. |
| • | Inspect for a stuck lock-up timing valve. |
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.
-
During the TCC enable solenoid valve operation, listen for an audible click. Command the ON and the OFF states. Repeat the commands as necessary.
Step | Action | Values | Yes | No | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||||||||
Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check | |||||||||||||||
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 PCM. Does the TCC PC Solenoid Functional Test Status display complete? | -- | Go to Diagnostic Aids | Go to Step 4 | |||||||||||||||
Does the TCC enable solenoid valve click with each command? | -- | Go to Step 5 | Go to Step 6 | |||||||||||||||
5 |
Did you complete the repair? | -- | Go to Step 7 | -- | ||||||||||||||
6 | Replace the TCC enable solenoid valve. Refer to Accumulator Valve Body Assembly Overhaul . Did you complete the replacement? | -- | Go to Step 7 | -- | ||||||||||||||
7 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | 93-102 % | Go to Step 8 | Go to Step 2 | ||||||||||||||
8 | 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? | -- | System OK |
