Code result
P25BB
Regeneration Control Switch Circuit Low
Moderate severity
What it means
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.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Switch wire shorted to ground
highOne of the most commonly reported causes for this code — check this first.
Connector pins corroded - high contact resistance
lowLess common, but worth ruling out after the more likely causes.
Harness chafing through insulation
lowLess common, but worth ruling out after the more likely causes.
Related help
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