P05BC
Stop-Start Mode Switch Circuit Open
The driver-controlled switch that disables stop-start has an open control circuit - the ECU cannot read the driver preference and falls back to the default mode.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Open in switch or harnessCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Stop Start Switch
P05BC 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.