P1860

DTC P1860





Circuit Description
The torque converter clutch pulse width modulated (TCC PWM) solenoid valve is a normally-closed solenoid used to control the apply and release of the converter clutch. The transmission control module (TCM) operates the solenoid with a negative duty cycle. When vehicle operating conditions are appropriate to apply the TCC, the TCM immediately increases the duty cycle to approximately 42 percent. The TCM then ramps the duty cycle to approximately 90 percent to achieve full TCC apply pressure. 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, short to ground or short to voltage in the TCC PWM solenoid valve circuit, DTC P1860 sets. DTC P1860 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1860 Torque Converter Clutch (TCC) Pulse Width Modulation (PWM) Solenoid Control Circuit

Conditions for Running the DTC
^ No TCC system DTCs P0741 or P0742.
^ The engine run time is greater than 5 seconds.
^ The TCC PWM solenoid valve duty cycle is less than 10 percent or greater than 80 percent.

Conditions for Setting the DTC
The TCM detects an open, short to ground or a short to voltage on the TCC PWM solenoid valve circuit for 4.3 seconds.

Action Taken When the DTC Sets
^ The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
^ The TCM inhibits TCC engagement.
^ The TCM freezes transmission adaptive functions.
^ 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.
^ 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 P1860 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.
^ 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 DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids
Ensure the wiring harness is not stretched too tightly or other components are pressing on the connector body. Also, inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections. Diagnostic Aids

Test Description











The numbers below refer to the step numbers on the diagnostic table.
7. This step tests the TCM and the wiring to the AT inline 20-way connector.
10. This step tests the control circuit for a short to voltage.
12. This step tests the circuit for correct resistance.