P1860

DTC P1860

Schematic:

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 PCM operates the solenoid with a negative duty cycle. When vehicle operating conditions are appropriate to apply the TCC, the PCM immediately increases the duty cycle to approximately 42 percent. The PCM then ramps the duty cycle to approximately 90 percent to achieve full TCC apply pressure. When the solenoid is commanded OFF, the PCM senses high voltage. When the solenoid is commanded ON, the PCM senses low voltage.
When the PCM detects a continuous open, short to ground or short to voltage in the TCC PWM solenoid valve circuit, then DTC P1860 sets. DTC P1860 is a type A DTC.

Conditions for Running the DTC
- The system voltage is 8 - 18 volts.
- The engine run time is greater than 5 seconds.
- The engine is not in fuel cut off.
- The TCC PWM solenoid valve duty cycle is less than 10 percent, or greater than 90 percent.
- The TP sensor is 10-90 percent.

Conditions for Setting the DTC
The PCM 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 PCM illuminates the Malfunction Indicator Lamp (MIL).
- The PCM inhibits TCC engagement.
- The PCM freezes transmission adapt functions.
- 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 P1860 in PCM history.

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.

Test Description

Steps 1-7:

Steps 8-17:

Steps 18-25:

The numbers below refer to the step numbers on the diagnostic table.
11. This step tests the PCM and the wiring to the AT inline 20-way connector.
14. This step tests the control circuit for a short to voltage.
16. This step tests the circuit for correct resistance.