P01EF
Engine Coolant Heater B Control Circuit Performance
Engine Coolant Heater B Control Circuit Performance: the control circuit has an electrical fault.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Heater element failedCommon
Parts involved
- Coolant Heater B
P01EF 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.