P1860

Torque Converter Clutch PWM Solenoid Wiring Schematic:

CIRCUIT DESCRIPTION
The purpose of the Torque Converter Clutch (TCC) feature is to eliminate the power loss of the torque convener when the vehicle is in a cruise condition. This allows the convenience of the automatic and the fuel economy of a manual transaxle. The heart of the system are two Powertrain Control Module (PCM) controlled solenoids located inside the transaxle.

When the TCC apply solenoid coil is activated "ON", the TCC is applied which results in a straight through mechanical coupling from the engine to the wheels. When the apply solenoid coil is deactivated "OFF", the TCC is released which allows the torque convener to operate in the conventional manner (fluidic coupling between engine and transaxle).

The TCC Pulse Width Modulated (PWM) solenoid is used to vary hydraulic pressure to the converter clutch regulator valve, allowing a smoother engagement of the converter clutch. The PCM uses a General FET Driver (GFD) to turn the TCC PWM solenoid "ON" and "OFF." The PCM monitors the electrical state of the GFD output and can detect a fault in the output circuitry.

DIAGNOSTIC TROUBLE CODE (DTC) P186O WILL SET WHEN
^ Incorrect voltage level is detected on TCC PWM solenoid circuit (CKT 418).
^ Above condition for over 5 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
With a current DTC P186O set, TCC may not be allowed to engage. DTC P186O does not illuminate the Malfunction Indicator Lamp (MIL).

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Ensures that the PCM is capable of controlling the TCC PWM solenoid driver properly.
2. Checks for CKT 418 shorted to ground.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.

Check for:
^ Poor connection or damaged harness - Inspect PCM harness connectors for backed out terminal "RA13", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.
^ Intermittent test - Monitor a digital voltmeter connected from affected terminal to ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change.