P251E
PTO Engine Shutdown Circuit Low
The PTO engine-shutdown command line reads stuck low — usually a short to ground or a permanently asserted shutdown request. The ECM may treat this as an active shutdown command and refuse to start or keep the engine running while in PTO mode.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Shutdown wire shorted to groundCommon
- Connector pins corroded - high contact resistanceLess likely
- Harness chafing through insulationLess likely
Parts involved
- Pto Shutdown Circuit
P251E is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.