Circuit Description
The PCM 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 PCM detects high torque converter slip when the TCC is commanded ON,
then DTC P0741 sets. DTC P0741 is a type B DTC.
Conditions for Running the DTC
• | No TP DTCs P0121, P0122 or P0123. |
• | No VSS DTCs P0502 or P0503. |
• | No AT ISS DTCs P0716 or P0717. |
• | No TCC stuck ON DTC P0742. |
• | No IMS DTCs P1820, P1822, P1823 or P1825. |
• | No TCC PWM solenoid valve DTC P1860. |
• | The engine run time is greater than 5 seconds. |
• | The time since the gear select lever change is greater than 6 seconds. |
• | The IMS indicates D2, D3 or D4. |
• | The transmission gear ratio indicates 2nd, 3rd or 4th gear. |
• | The transmission fluid temperature is 20-133°C (68-271°F). |
• | The TP angle is 10-50 percent. |
• | The engine torque is 43-215 N·m (32-159 lb ft). |
• | The TCC solenoid valve is commanded ON. |
Conditions for Setting the DTC
TCC slip speed exceeds its limit for a given torque for 5 seconds.
Refer to
Torque Converter Clutch Slip Speed
.
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 inhibits 4th gear if the transmission is in hot mode. |
• | 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 during the second consecutive
trip in which the Conditions for Setting the DTC are met. |
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 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
| Value(s)
| Yes
| No
|
1
| Did you perform the Powertrain Diagnostic System Check?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Engine Controls
in Engine Controls
|
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 PCM.
- 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 20-133°C (68-271°F). |
• | The engine torque is 43-215 N·m (32-159 lb ft). |
• | Drive the vehicle in D4 with a throttle position (TP) angle of 10-50 %. |
• | 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 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.
Refer to
Transmission Overhaul
in the 4T80-E section of the Transmission Unit Repair Manual.
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 20-133°C (68-271°F). |
• | The engine torque is 43-215 N·m (32-159 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 +100 RPM
for 4 seconds. |
- Select Specific DTC.
- Enter DTC P0741.
Has the test run and passed?
| --
| System OK
| Go to
Step 1
|