Circuit Description
The ignition 1 voltage is supplied to the torque converter clutch pulse width modulated (TCC PWM) solenoid valve. The transmission control module (TCM) controls the ON and OFF time of the TCC PWM solenoid by controlling the ground side of the TCC solenoid valve control circuit. The TCM uses a PWM duty cycle, in order to control application and release of the TCC. When the solenoid is commanded OFF, the TCM senses high voltage. When the solenoid is commanded ON, the TCM senses low voltage.
When the TCM detects a continuous open or short to ground in the TCC Solenoid valve control circuit, then DTC P2764 sets. DTC P2764 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2764 Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid Control Circuit Low Voltage
Conditions for Running the DTC
The engine run time is greater than 5 seconds.
Conditions for Setting the DTC
DTC P2764 sets when the TCM detects an open and short to ground in the TCC PWM solenoid valve circuit.
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 commands TCC ON. |
| • | The TCM freezes transmission adaptive function. |
| • | 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 P2764 in TCM history. |
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 default actions when the ignition is OFF long enough in order to power down the TCM. |
Diagnostic Aids
| • | Rapid fluctuation in line pressure may set DTC P0742. Refer to Line Pressure Check . |
| • | The customer may notice an engine stalling condition. |
| • | Potentially DTC P0742 can false fail and may have been set due to another DTC. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
Important:
Does the solenoid click when commanded ON and OFF? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |||||||
3 |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 7 | ||||||
4 |
Refer to Component Resistance . Does the resistance measure within the specified range? | 10.0-15.0ohms | Go to Step 5 | Go to Step 8 | ||||||
5 | Using the DMM, measure the resistance between terminal U of the J 44152 and ground. Does the resistance measure greater than the specified value? | 50Kohms | Go to Step 6 | Go to Step 8 | ||||||
6 |
Refer to Testing for Continuity , Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||||
7 |
Refer to Testing for Continuity , Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 12 | -- | ||||||
8 | Test the TCC PWM solenoid wiring from the 20-way connector to the TCC PWM solenoid connector for the following conditions:
Refer to Testing for Continuity and Testing for Short to Ground . Did you find a condition? | -- | Go to Step 10 | Go to Step 11 | ||||||
9 | Replace the TCM. Refer to Control Module References . Is the action complete? | -- | Go to Step 12 | -- | ||||||
10 |
Important: The automatic transmission wiring harness consists of two separate harnesses, the Automatic Transmission Wiring Harness Assembly and the Automatic Transmission Wiring Extension Harness Assembly. In order to avoid the unnecessary replacement of parts, only replace the Automatic Transmission Wiring Harness Assembly. Replace the automatic transmission wiring harness. Refer to Input Speed Sensor and Wiring Harness Removal in the 4T80-E section of the Transmission Unit Repair Manual. Is the action complete? | -- | Go to Step 12 | -- | ||||||
11 | Replace the TCC PWM solenoid valve. Refer to Control Valve Upper Body Disassemble in the 4T80-E section of the Transmission Unit Repair Manual. Is the action complete? | -- | Go to Step 12 | -- | ||||||
12 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 13 | Go to Step 2 | ||||||
13 | 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 |
