P2500
Generator Lamp/L-Terminal Circuit Low
The L-terminal feedback line from the alternator (charging warning lamp circuit) reads below the lower limit. The lamp may stay on, and battery voltage may drift if regulation feedback is also affected.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- L-terminal shorted to groundCommon
- Alternator regulator failedPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Alternator
- Charging Warning Lamp Wiring
P2500 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.