P25BB: Regeneration Control Switch Circuit Low
Standardized SAE J2012 code · P25xx — Auxiliary inputs
What does P25BB mean?
Regeneration control switch input reads stuck low — short to ground or stuck-closed contact. The ECM may see a constant regen request which it cannot service while the vehicle is moving.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Switch wire shorted to ground
- Low Connector pins corroded - high contact resistance
- Low Harness chafing through insulation
Likelihood is a general estimate across vehicles; your make and model may differ.
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P25BB in the community
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