Gear Shift Control Module A Communication Circuit High
What it means
P0862 means the voltage on the communication line to gear shift control module "A" is abnormally high, so the transmission control system can't reliably talk to the shift-by-wire module that reports and commands gear position. The engine still starts, but if that link fails the transmission may stick in a gear or stop shifting. It's a wiring/communication fault worth diagnosing before drivability gets worse.
Can I keep driving? The engine starts, but if the shift control module stops communicating the transmission may stick in one gear or refuse to shift; drive as little as possible until it's diagnosed.
Common symptoms
What you'll notice
- Check-engine light on
- Delayed, erratic, or missing gear changes
- Transmission stuck in one gear
- Unable to shift at all in some cases
Common causes
Most likely first
- Open or short to power on the gear shift module communication circuit (reads high)Likely
- Loose or corroded connector at the gear shift moduleCommon
- Faulty gear shift control moduleCommon
- Failed transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the module connector and communication wiring for damage or shorts to power.
- Check continuity and voltage on the communication circuit between the shift module and TCM with a meter.
- Test the gear shift control module and replace it if it fails to communicate.
- If the circuit and module are good, suspect the TCM. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0862?+
Can I just clear P0862?+
Related codes
Often seen with P0862
Read & clear P0862 yourself
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