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P0860 OBD-II Trouble Code: Gear Shift Module Communication Circuit

diagnostic check engine light

P0860 code definition

The P0860 code is a generic powertrain code related to the transmission, including pressure faults and sensor failures. In this case, the engine control module (ECM) has detected a fault with the gear shift module communication circuit.

What the P0860 code means

A code P0860 will be stored when the EMC has found a fault or error in the gear shift module communication circuit.

Note, the P0860 code will only apply to vehicles with an electronic traction control system.

The gear shift module communication circuit sends information through the vehicle’s controller area network (CAN) to the ECM, in addition to other controllers, to help calculate efficient vehicle operation. The CAN is a communication bus that helps different vehicle modules communicate with each other. The gear shift module helps the vehicle determine the proper gear shift timing.

What causes the P0860 code?

Several problems may cause a P0860 code including:

  • Damaged, open, or shorted wiring or connectors and related components
  • Damaged or defective manual lever position sensor
  • Excessive moisture levels in the gear shift module sensor connector

What are the symptoms of the P0860 code?

Symptoms of a P0860 code may include:

  • Check engine or warning light may illuminate
  • Traction control malfunction light may blink or stay illuminated
  • Reduced fuel economy
  • Vehicle may lack traction during slippery road conditions
  • Vehicle may shift roughly
  • Vehicle may not shift into or out of any gear
  • Vehicle may enter “limp” mode

How does a mechanic diagnose the P0860 code?

A mechanic may use several methods to diagnose a P0860 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored P0860 trouble code
  • Visually inspect all wiring and connectors related to the gear shift module for possible damage or corrosion
  • Use a specialized tool (such as an Autohex) to help pinpoint the error or malfunction
  • Use a memory saving device to store the memory of other modules during reprogramming
  • Use a diagnostic CAN scanner to see pin values and which control modules are in operation
  • Test control module ground circuits for continuity with battery ground
  • Check for loose or corroded electrical connectors that could increase the circuit’s resistance

Common mistakes when diagnosing the P0860 code

At times, the gear shift module is incorrectly determined to be the cause of the P0860 code, when the actual problem is in the electrical wiring or with a switch or sensor. It is recommended to fully diagnose any fault or trouble code prior to making repairs.

How serious is the P0860 code?

Because a vehicle’s safe driving operation most likely will be impacted due to faults that store a P0860 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What repairs can fix the P0860 code?

Several repairs can fix a P0860 trouble code and include:

Additional comments related to the P0860 code

As with any trouble code or maintenance problem related to the controller area network (CAN), the large amount and bulk of electrical circuitry.

Need help with a P0860 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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