Circuit Description
The transmission control module (TCM) provides voltage to the torque converter clutch pulse width modulated (TCC PWM) solenoid valve through High Side Driver 2 (HSD2). The TCM controls the ON and OFF time of the solenoid by providing a ground through the output driver module (ODM) . 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 PWM Solenoid valve circuit, then DTC P1866 sets. DTC P1866 is a type B DTC.
Conditions for Running the DTC
| • | The system voltage is 8-18 volts. |
| • | The engine run time is greater than 5 seconds. |
| • | HSD2 is commanded ON. |
Conditions for Setting the DTC
DTC P1866 sets when either of the following conditions occurs:
| • | The TCM detects an open in the TCC PWM solenoid valve circuit when the PWM duty cycle is greater than 20 percent. |
| • | The TCM detects a short to ground in the TCC PWM solenoid valve circuit when the PWM duty cycle is greater than 20 percent but less than 50 percent. |
Action Taken When the DTC Sets
| • | The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive drive trip in which the Conditions for Setting the DTC are met. |
| • | The TCM turns off power to all solenoids. When the solenoids are off: |
| - | The transmission will operate in fifth gear if the vehicle has successfully completed a 1-2 upshift in the current ignition cycle. If the vehicle has not completed a 1-2 upshift in the current ignition cycle, the transmission will operate in fourth gear. If the transmission is operating in fifth gear, fourth gear may be obtained if the engine is stopped briefly and started again. |
| - | The line pressure is at maximum, and updates to the transmission adaptive pressure (TAP) memory cells are discontinued. |
| • | Torque management is inhibited. |
| • | At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record. |
| • | At the time of the second failure, the ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame. |
| • | The TCM stores DTC P1866 in TCM history. |
Conditions for Clearing the MIL/DTC
| • | The ECM turns OFF the MIL after the sixth consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | 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. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.6L and 3.2L | ||||||
Important:
Does the solenoid operate? | -- | Go to Step 9 | Go to Step 3 | |||||||
3 |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 7 | ||||||
4 |
Refer to Component Resistance . Is the resistance within the specified range? | 10.0-13.6ohms | Go to Step 5 | Go to Step 8 | ||||||
5 | Using the DMM, measure the resistance between terminal 17 of the J 45681 and ground. Is the resistance greater than the specified value? | 50K ohms | Go to Step 6 | Go to Step 8 | ||||||
6 |
Did you find a condition? | -- | Go to Step 10 | Go to Step 9 | ||||||
7 |
Did you find a condition? | -- | Go to Step 10 | Go to Step 9 | ||||||
8 |
Did you find a condition? | -- | Go to Step 11 | Go to Step 12 | ||||||
9 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 13 | -- | ||||||
10 | Perform the necessary wiring repairs. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 13 | -- | ||||||
11 | Replace the AT internal transmission wiring harness. Refer to Transmission Internal Electrical Harness Replacement . Is the action complete? | -- | Go to Step 13 | -- | ||||||
12 | Replace the TCC PWM solenoid valve. Refer to Torque Converter Clutch Solenoid Replacement . Is the action complete? | -- | Go to Step 13 | -- | ||||||
13 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 14 | Go to Step 2 | ||||||
14 | 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 in Engine Controls - 2.6L and 3.2L | System OK |
