P1860

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) is a normally closed solenoid used to control the apply and release of the converter clutch. The Powertrain Control Module (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 low voltage. When the solenoid is commanded ON, the PCM senses high voltage.

When the PCM detects a continuous open, short to ground or short to power in the TCC PWM Sol. Valve circuit, then DTC P1860 sets. DTC P1860 is a type A DTC.

CONDITIONS FOR SETTING THE DTC

^ The system voltage is 9-16 volts.

^ The engine has been running for more than 5 seconds, and is not in fuel cut off.

^ The TCC PWM Sol. Valve duty cycle is less than 10% or greater than 90%.

^ The PCM detects an open, short to ground or a short to power on the TCC PWM Sol. Valve circuit within 5 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.

DTC P1860 is stored in PCM history.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS

^ Inspect the wiring at the PCM, the transmission 20-way connector and the TCC PWM Sol. Valve 2-way connector for the following conditions:

- A bent terminal.

- A backed out terminal.

- A damaged terminal.

- Poor terminal tension.

- A chafed wire.

- A broken wire inside the insulation.

- Moisture intrusion.

- Corrosion.

^ Ensure that the transmission fluid is at the proper level.

^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table.

2. DTCs P0753 and P0758 set if the power circuit is open.

11. This step tests the PCM and the wiring to the transmission 20-way connector.

14. This step tests circuit 418 for a short to battery power.

16. This step tests the circuit for correct resistance.