Circuit Description
The PCM controls the torque converter clutch pulse width modulation
(TCC PWM) solenoid valve. The solenoid controls the hydraulic fluid
for TCC apply and release. When the TCC is fully applied, the engine is coupled
directly to the transmission through the TCC.
The TCC used is an electronically controlled capacity clutch (ECCC).
The PCM will normally allow a small amount of slip to occur with the ECCC.
When the TCC is engaged, TCC slip speed is maintained at approximately 20
to 50 RPM.
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 sensor DTC P0121, P0122 or P0123. |
• | No VSS DTC P0502 or P0503. |
• | No AT ISS sensor DTC P0716 or P0717. |
• | No TCC stuck ON DTC P0742. |
• | No TFP manual valve position switch DTC P1810. |
• | No TCC PWM solenoid valve DTC P1860. |
• | No TCC release switch DTC P1887. |
• | The engine speed is greater than 500 RPM for 5 seconds
and not in fuel shut off. |
• | The transmission gear range is D4, D3 or D2. |
• | The time since the last gear range change is greater than 6 seconds. |
• | The transmission fluid temperature is 20-130°C (68-266°F). |
• | The TCC PWM solenoid valve is commanded ON for more than
0.5 seconds. |
• | The TCC is at maximum apply pressure. |
Conditions for Setting the DTC
The TCC slip speed is greater than 180 RPM two times for 7 seconds
each, during the same ignition cycle.
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 freezes shift adapts. |
• | 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 the PCM history if the vehicle completes
40 consecutive warm-up cycles without an emission-related diagnostic fault
occurring. |
• | The PCM cancels the DTC default actions when the fault no longer
exists and the ignition switch is OFF long enough in order to power down the
PCM. |
Diagnostic Aids
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step verifies that the TCC engages when commanded ON by the Scan Tool
.
DTC P0741 TCC System Stuck Off
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Powertrain
Diagnostic System Check?
| --
|
Go to Step 2
| Go to
Powertrain On Board Diagnostic (OBD) System Check
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
.
- Start the engine.
Important: Before clearing the DTCs, use the Scan Tool
in order to record the Freeze Frame and Failure Records for
reference. Using the Clear Info function will erase the stored Freeze Frame
and Failure Records from the PCM.
- Record the Freeze Frame and Failure Records.
- Clear the DTCs.
- With the Scan Tool
, observe TCC release pressure.
Does the Scan Tool
indicate TCC release pressure is present?
| --
|
Go to Step 5
|
Go to Step 4
|
4
|
- Inspect the following components:
• | The TCC regulator apply valve |
• | The TCC PWM solenoid valve |
• | The pressure regulator valve |
- Repair or replace any malfunctioning components.
Refer to
Transmission Overhaul
in the 4T65-E Section of the Transmission Unit Repair Manual.
Did you complete the repair?
| --
|
Go to Step
7
| --
|
5
|
- Drive the vehicle above 72 km/h (45 mph) with a
TP angle of less than 30%.
- With the Scan Tool
, command the TCC PWM solenoid valve ON and monitor the TCC
slip speed display.
Does the Scan Tool
indicate the slip speed is within the specified value?
| -50 RPM to +50 RPM
| Go to
Diagnostic Aids
|
Go to Step 6
|
6
|
- Inspect the following components:
• | The TCC control valve for sticking |
• | The TCC regulator valve for sticking |
• | The TCC PWM solenoid valve and O-ring seal for leaking |
• | The TCC PWM solenoid valve filter for plugging |
• | The turbine shaft seals for leaks |
• | The torque converter clutch |
- Repair or replace the component as necessary.
Refer to
Transmission Overhaul
in the 4T65-E Section of the Transmission Unit Repair Manual.
Did you complete the inspection or repair?
| --
|
Go to Step 7
| --
|
7
| Perform the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Drive the vehicle in D2, D3 or D4 until the TCC is engaged.
• | TP angle must be 4-35%. |
• | Time since the last gear range change must be greater than 6 seconds. |
• | The TCC is commanded ON at greater than 50% duty cycle. |
• | TCC slip speed must be less than 50 RPM for at least 4 seconds. |
- Select Specific DTC.
- Enter DTC P0741.
Has the test run and passed?
| --
| System OK
|
Go to Step
1
|