P0388Crankshaft Position Sensor B Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Some engines have a second crankshaft sensor or a second track on the tone wheel – GM's 3.4/3.5/3.8-litre V6 use the low resolution track of a dual Hall sensor, the Honda 3.5-litre in the Saturn Vue Redline a second sensor – which the engine module checks against sensor A or the camshaft. By its J2012 name P0388 means the signal of sensor B stays above its upper limit – with a Hall sensor typically an open signal wire held high by the module's pull-up, or a short to positive. No manufacturer document available to us uses P0388: the engines with a sensor B report its electrical faults under P0385 and implausible signals under P0386. The description therefore follows the J2012 name, these component sources and CARB's monitoring requirement for crank angle sensors. The engine usually keeps running on sensor A; longer cranking is possible.
- What you may notice
- Check engine light on
- Longer cranking or starting problems
- Possibly rough running or misfire
- Often no noticeable symptoms while sensor A takes over
- Likely causes
- LikelySignal wire of sensor B open or connector corroded or loose
- PossibleSignal wire shorted to positive or reference voltage
- PossibleSensor ground open
- PossibleSensor B faulty internally
- RareEngine module input
- 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: €60 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.