P2535
Ignition Switch On/Start Position Circuit High
The On/Start input reads stuck high — short to battery voltage. The ECM cannot read the crank state, modules dependent on this signal are unable to time their wake-up correctly.
- 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 battery voltageCommon
- Connector pins corroded - high contact resistanceLess likely
- Supply wire pinched against B+ sourceLess likely
Parts involved
- Ignition Switch
- Wiring Harness
P2535 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.