P2534
Ignition Switch On/Start Position Circuit Low
The On/Start input reads stuck low — short to ground or permanently closed contact. The ECM may see crank request when the key is at rest, blocking accessory functions or causing unexpected starter cut-off logic.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- On/Start wire shorted to groundCommon
- Connector pins corroded - high contact resistanceLess likely
- Harness chafing through insulationLess likely
Parts involved
- Ignition Switch
- Wiring Harness
P2534 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.