P2500Generator Lamp/L-Terminal Circuit Low
- Generic OBD-II code · Powertrain
- How the car detects it
- P2500 points to the L line, the turn-on wire between engine module and alternator regulator that on many older layouts also runs through the charge warning lamp. The module reads back the voltage on this wire; when it stays below the expected level, for instance because the line is chafed to ground or the regulator holds it down, this code is logged. A line pinned low can mean the regulator never receives its start command, so the field is not energised and the battery slowly drains. Ford lists P2500 in the code table of its 2014 BOSS 302S engine module, without a MIL marker; no maker publishes trigger values. P0621 covers the L circuit in general, P2501 is the high counterpart. The driver may see the battery lamp and later a weak or dead battery.
- What you may notice
- Battery or charge warning lamp on
- Battery voltage falls while driving
- Hard or no start after some time
- Likely causes
- LikelyL wire chafed through and shorted to ground
- PossibleAlternator regulator faulty and pulling the L terminal low
- PossibleCorroded or loose plug at the alternator
- RareOutput stage for the L line in the engine module defective
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.