What are the common causes of P0855?

An open in the drive switch input wire. A drive switch stuck open. A backed out drive switch connector pin. A TCM or ECM fault.

Read drive switch input voltage. Test the input wire for an open. Wiggle test the drive switch connector. Check the TCM and ECM for stored faults. Replace the switch if the signal stays high. Clear the code and retest.

P0855

Drive Switch Input Circuit High

System: Transmission (P code)
Lamp: Check Engine Light
Category: Powertrain - Transmission

What it means

P0855 means Drive Switch Input Circuit High.

Where it lives

For P0855, the circuit described runs through the switch. The description of P0855 reports a fault at the switch.

Check these first

An open in the drive switch input wire
A drive switch stuck open
A backed out drive switch connector pin
A TCM or ECM fault

What to do next

Read drive switch input voltage
Test the input wire for an open
Wiggle test the drive switch connector
Check the TCM and ECM for stored faults
Replace the switch if the signal stays high
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.