P05E8
Engine Oil Bypass Valve Control Circuit Open
The oil bypass valve - which routes oil around the cooler to speed up warm-up - has an open control circuit. Without it, oil temperature rise during cold-start is slower than calibrated.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open in valve or harnessCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Oil Bypass Valve
P05E8 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.