Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Ignition voltage is provided to the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. The PCM controls the solenoid with a negative duty cycle in order to control application and release of the TCC. When the solenoid is commanded OFF, the PCM senses high voltage. When the solenoid is commanded ON, the PCM senses low voltage.
If the PCM detects a continuous open, short to ground or short to voltage in the TCC PWM valve circuit, then DTC P1860 sets. DTC P1860 is a type B DTC.