OBD-II Code · Network
P0860
Gear Shift Module Communication Circuit
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$200–$1,500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Communication between shifter module and TCM/PCM lost.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Cannot shift
- PRNDL display blank
- Check engine light
Likely causes
- Failed shifter moduleMost common
- Wiring
- CAN bus
Read the full diagnostic procedureP0860 sets when the PCM or BCM cannot communicate with the Gear Shift Module over the CAN bus — the controller is sending a request to the GSM (the e…
P0860 sets when the PCM or BCM cannot communicate with the Gear Shift Module over the CAN bus — the controller is sending a request to the GSM (the electronic shifter module on shift-by-wire vehicles) and either gets no response or gets a malformed response within the protocol timeout window. On a typical 500 kbps CAN bus the dominant state is ~2.5V on CAN-low and ~3.5V on CAN-high, with the recessive state at ~2.5V on both wires; a healthy bus shows steady oscillation between those states under scope.
Cheapest-first ladder
- Key-on and scope CAN-H and CAN-L at the gear shift module connector — both should show clean differential traffic. A flat-line on either wire means the bus is broken between the module and the rest of the network.
- Pull the GSM connector and check the module-side resistance between CAN-H and CAN-L; should read ~60 ohms (two 120-ohm terminators in parallel). Anything above ~80 ohms means one terminator is missing or the bus is broken; anything under ~40 ohms means a shorted module is loading the bus.
- Disconnect the GSM and watch the rest of the bus continue operating — if the network recovers and other modules talk again, the GSM is the failed node. Expensive-misdiagnosis caveat: P0860 with a no-shift complaint will tempt a shop to quote a TCM or valve body, but on shift-by-wire vehicles (Jaguar XF rotary, Lincoln MKZ push-button, Acura ZDX) the actual fault is usually a $300-$500 gear shift module that has lost CAN communication; replacing the transmission won't fix the code.
Vehicle-specific patterns2009-2015 Jaguar XF / XJ with the ZF 6HP and the famous rotary shift dial throws P0860 from a failed JaguarDrive Selector module — the rotary lifts o…
- 2009-2015Jaguar XF / XJ with the ZF 6HP and the famous rotary shift dial throws P0860 from a failed JaguarDrive Selector module — the rotary lifts out of the console on key-on and the failure mode is no-lift plus no-shift.
- 2013-2020Lincoln MKZ / Continental with the push-button shifter throws P0860 from a failed shifter module; Ford issued a TSB on early MKZ shift-by-wire units.
- 2010-2013Acura ZDX and 2014+ Acura TLX/MDX with the push-button shifter throws P0860 from a CAN comm fault at the integrated shift module — Acura's symptom is the gear indicator going blank on the dash.
- 2014-2019Ram 1500 with the rotary shifter throws P0860 from a failed shift module; the truck strands in Park and refuses to engage gear.
Estimated repair$300 to $1,200.
Look up another code
P0860 — frequently asked
What does a P0860 code mean?
Communication between shifter module and TCM/PCM lost.
What causes a P0860 code?
Common causes: Failed shifter module; Wiring; CAN bus.
What are the symptoms of a P0860 code?
Typical symptoms: Cannot shift; PRNDL display blank; Check engine light.
Is it safe to drive with a P0860 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $200-$1,500.
How do I diagnose a P0860 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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