P1860

Circuit Description with 4T80-E Automatic Transaxle

Torque Converter Clutch (TCC) Pulse Width Modulation (PWM) Solenoid Circuit Schematic:

Ignition voltage is provided to the Torque Converter Clutch Pulse Width Modulation (TCC PWM) solenoid valve. The PCM controls the ON and OFF time of the solenoid by providing a ground through the output driver Module (ODM). The PCM uses a PWM duty cycle, in Order To Control application and release of the TCC. When the solenoid is commanded OFF, the PCM senses high volts. When the solenoid is commanded ON, the PCM senses low volts. If 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 B 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 10% or less or 90% or greater.

CONDITIONS FOR SETTING THE DTC
The TCC PWM solenoid valve feedback circuit indicates a continuous open, short to ground or short to voltage for 4.3 seconds.

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 TCC engagement.
^ The PCM inhibits 4th gear when the transmission is in hot mode.
^ 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 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 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 fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS
^ Inspect the connectors at the PCM, the TCC PWM solenoid valve and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Diagrams.
^ Ensure that the transmission fluid is at the proper level.

TEST DESCRIPTION

Steps 1 - 4:

Steps 5 - 14:

Steps 15 - 24:

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.