P00E4
Exhaust Heat Exchanger Exhaust Bypass Valve A Stuck Closed
The exhaust heat exchanger bypass valve A is stuck closed. Risk of overheating because exhaust always passes through the heat exchanger.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Valve stuck closed by carbonCommon
- Carbon or debris buildup preventing free movementLess likely
- Component wear with age - mechanical playLess likely
Parts involved
- Exhaust Bypass Valve A
- Heat Exchanger
P00E4 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.