P1860

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Schematic:

CIRCUIT DESCRIPTION
The Torque Converter Clutch Pulse Width Modulation (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%. The PCM then ramps the duty cycle to approximately 90% 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 has been running for more than 5 seconds, and is not in fuel cut off.
^ The TCC PWM solenoid valve duty cycle is less than 10% or greater than 90%.

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 shift adapts from being updated.
^ 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 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
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.