P1860 - FAULT CODE - OBD2

P1860 BUICK, CADILLAC, CHEVROLET, GMC, OLDSMOBILE, PONTIAC, SATURN: TCC PWM SOLENOID CIRCUIT ELECTRICAL

The Torque Converter Clutch Pulse Width Modulation Solenoid (TCC PWM) controls the fluid passing over the converter clutch valve, which regulates the application and release of the TCC.

The PWM TCC is attached to the control valve body, which is located inside the transmission. The PCM (Powertrain Control Module) provides a ground signal on circuit 418 to the solenoid. Current is sent through the solenoid coil, taking into account the duty cycle, which translates into the percentage on/off time. This solenoid provides smooth clutch engagement by operating for a percentage of the duty cycle.

If the PCM notices a continuous open, short to ground, or power on the TCC PWM Solenoid TCC circuit, the P1860 OBD2 fault code will be set.

• Check Engine light illuminated.

Reasons to set the P1860 OBDII DTC P1860:

• The TCC PWM Solenoid TCC circuit wiring or connections may be faulty.
• The Torque Converter Clutch Pulse Width Modulation Solenoid may have a short in its circuit.
• Possibly the TCC PWM solenoid is faulty.

Steps to solve the P1860 OBD2 diagnostic code:

• Consult the TSB.
• Verify that the TCC PWM Solenoid circuit is not faulty in its wiring or connectors. If deficiencies are discovered due to common damage, make repairs if necessary.
• Measure the TCC PWM Solenoid circuit voltages to verify that there is no short or open circuit. If you find such conditions, make the respective corrections.
• Check the integrity of the Torque Converter Clutch Pulse Width Modulation Solenoid, following the diagnostic steps outlined in the vehicle information source. If the solenoid does not meet the minimum requirements for proper operation, make the replacement.