P0387Crankshaft Position Sensor B Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- By its J2012 name P0387 means the signal of the second crankshaft sensor stays at a low level – typically a short to ground of the signal wire, a missing or shorted sensor supply, or with an inductive sensor an amplitude that is too small. No manufacturer document available to us uses P0387: the engines with a sensor B that we found (GM Northstar 4.6 and 3.8-litre V6, the Honda 3.5-litre in the Saturn Vue Redline) report its electrical faults under P0385 and implausible signals under P0386. The description therefore follows the J2012 name, the function of sensor B and CARB's monitoring requirement for crank angle sensors. As long as sensor A works, the engine usually keeps running; together with a sensor A fault it may not start.
- What you may notice
- Check engine light on
- Longer cranking
- Rough running, no start if sensor A also fails
- Likely causes
- LikelySignal wire shorted to ground
- PossibleSensor faulty
- PossibleSensor supply too low or shorted
- RareEngine module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.