P0860: Gear Shift Control Module A Communication Circuit
What to do
The selector may be ignored entirely. Use the parking brake whenever you leave the vehicle — with the selector module not communicating, the transmission may not have received the park request at all, and the dashboard display is your only confirmation. If the car will not move, have it recovered rather than forcing the lever.
What this code means
Communication with the gear shift module has failed. On a shift-by-wire vehicle the selector is not a switch on a wire — it is a small module of its own, which reads the lever and reports the driver's intention as a message on the data bus.
That makes this the communication counterpart to the sensor faults under P0820, and the consequence is the same by a different route: the transmission no longer knows what the driver wants. Modules faced with that silence hold their last known state or fall back to a safe default rather than guess, so the vehicle typically stays in whatever range it was in, or refuses to leave park.
Everything said under P0820 about park being a request rather than a mechanical fact applies here with more force, because here the request is not even arriving.
Likely causes
Start here
- Faulty gear shift module · specialist
- Damaged data bus wiring · specialist
- Corroded or loose connector · easy
Less common
- Liquid spilled into the gear selector · moderate
- Poor module ground connection · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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