What are the common causes of P251D?

Open wire in the PTO engine shutdown circuit. Failed PTO shutdown switch. Failed shutdown relay in the PTO circuit. Corroded or disconnected PTO shutdown connector.

Inspect the PTO shutdown circuit wiring for opens. Test the PTO shutdown switch for continuity. Check the shutdown relay and swap it with a known-good one. Inspect the PTO shutdown connector for corrosion. Repair the open in the shutdown circuit. Clear the code and retest.

P251D

PTO Engine Shutdown Circuit/Open

System: Speed and idle control (P code)
Lamp: Check Engine Light
Category: Powertrain - Computer and Auxiliary Controls

What it means

P251D means PTO Engine Shutdown Circuit/Open.

Check these first

Open wire in the PTO engine shutdown circuit
Failed PTO shutdown switch
Failed shutdown relay in the PTO circuit
Corroded or disconnected PTO shutdown connector

What to do next

Inspect the PTO shutdown circuit wiring for opens
Test the PTO shutdown switch for continuity
Check the shutdown relay and swap it with a known-good one
Inspect the PTO shutdown connector for corrosion
Repair the open in the shutdown circuit
Clear the code and retest

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Updated

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