P25BA
Regeneration Control Switch Circuit/Open
The DPF/SCR forced-regeneration request switch — used on commercial vehicles to let the operator force a parked regeneration when the automatic regen has been postponed too often — is open. The ECM cannot honour an operator request for forced regen.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open switch wireCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Regen Request Switch
- Wiring Harness
P25BA 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.