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P1860 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P1860 is an OBD-II Code that refers to TCC PWM Solenoid Circuit Electrical OBD-II Trouble Code


A P1860 code is a generic diagnostic trouble code that occurs when the PCM/ECM receives a signal indicating the torque converter clutch is not functioning properly due to an issue with the solenoid which is used to activate it. The PWM TCC is secured to the transmission’s control valve body, which is nested inside of it.

By operating for a percentage of the duty cycle, this solenoid provides smooth clutch engagement. If the PCM detects a persistent open, short to ground, or power issue on the TCC PWM Solenoid TCC circuit, the P1860 OBD2 fault code will be set.


Common causes for this code include:

  • The TCC PWM Solenoid TCC circuit wiring or connections may be damaged.
  • The Torque Converter Clutch Pulse Width Modulation Solenoid might be faulty.
  • Bad TCC PWM solenoid


The symptoms of a P1860 code are:

  • Illuminated Check Engine Light 
  • Engine might stall
  • Noticeable poor engine performance
  • Upshifts/downshifts that have failed
  • Slipping
  • The transmission may begin to overheat


To diagnose a P1860 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the wiring harness and connectors for damage.
  3. Test the TCC PWM Solenoid with a multimeter for correct resistance.
  4. Check for open, short to ground, or power on the TCC PWM Solenoid circuit.
  5. Clear codes and road test the vehicle to see if the code returns.
  6. Repair as necessary.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P1860 code:

  • Not thoroughly inspecting all the wiring and connectors.
  • Not checking the TCC PWM Solenoid for correct resistance.
  • Not clearing the codes and road testing the vehicle.
  • Repairing the wrong component.

How serious is this?

A P1860 code is considered a mid-level code, so it will likely cause your engine to run poorly. If not fixed, it could also cause your transmission to overheat and fail.

What repairs can fix the code?

repair manuals

The following are solutions that may fix this problem:

  • Check the TCC PWM Solenoid circuit for any faulty wiring or connections. If problems are identified as a result of typical damage, make appropriate repairs.
  • Provide regular maintenance for the transmission (i.e. change the transmission fluid and filter)
  • Replace the TCC PWM solenoid

Related codes

A P1860 is related to and may be accompanied by the following codes:

P0700 – Transmission Control System (Malfunction)

P0717 – Turbine Speed Sensor Circuit No Signal

P0732 – TCC Mechanism Slipping

P0740 – Torque Converter Clutch Circuit Malfunction


In conclusion, the P1860 code is a diagnostic trouble code that refers to a problem with the TCC PWM solenoid. This code may cause the engine to run poorly and the transmission to overheat and fail. To fix this problem, a technician may need to check the TCC PWM Solenoid circuit for any faulty wiring or connections, provide regular maintenance for the transmission, or replace the TCC PWM solenoid.