P0388 — Crankshaft Position Sensor B Circuit High Input
Drive with caution — fix soon.
What P0388 means
This code means the engine computer detected a high voltage signal from crankshaft position sensor B. It's usually caused by an open circuit, a wiring fault, a failing sensor, or a loss of ground reference. It's a common circuit code and is typically repaired by fixing the wiring or replacing the sensor.
Common symptoms
- Check engine light is on
- Engine stalls or is hard to start
- Rough idle or misfires
- Hesitation or reduced power
- Intermittent no-start conditions
Common causes
- Open circuit in the sensor wiring
- Failing crankshaft position sensor B
- Corroded or loose connector at the sensor
- Loss of ground reference in the circuit
- Wiring damage causing high resistance
Typical repair cost
$150 – $500
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0388 code?
Short trips are usually fine, but don't rely on it. A high or unstable crankshaft signal can cause stalling or a no-start, so it's smart to get it checked before the sensor or wiring fails completely.
How much does it cost to fix a P0388 code?
Repairs generally cost $150 to $500. Fixing wiring or a connector can be cheaper, while replacing the sensor with labor sits in the middle to upper part of that range.
Is a P0388 code serious?
It's moderate. The engine may keep running for now, but an unreliable crankshaft signal can lead to sudden stalling, so it shouldn't be ignored for long.
What usually causes the high input in a P0388 code?
High input often comes from an open circuit or a broken wire that lets the voltage float high, rather than the sensor itself. Corroded connectors and a lost ground are also common culprits worth checking first.