P28F8
Exhaust Pressure Too High Bank 2
The exhaust pressure measured on bank 2 exceeds the calibrated maximum. Common causes are clogged DPF, restricted exhaust path, or stuck exhaust brake/back-pressure valve.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- DPF clogged with soot or ashCommon
- Back-pressure valve stuck closedPossible
Parts involved
- Exhaust Pressure Sensor B2
- Particulate Filter
- Exhaust System
P28F8 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.