P0387 - Crankshaft Position Sensor B Low Input

The ECM detected a crankshaft position sensor B low input fault.

Code Overview

The ECM detected a crankshaft position sensor B low input fault.

Common Causes

• Failed crankshaft position sensor
• Damaged wiring or connector
• Reluctor or timing problem affecting the signal

Diagnostic Steps

1. Inspect the sensor connector and harness
2. Check RPM signal during crank and run
3. Look for timing or reluctor issues if the signal is unstable

Likely Repairs & Cost Guides

Use test results to confirm the fault before pricing the repair.

Related OBD Codes

Browse the closest code-family pages when the same fault pattern often shows up nearby.

Next Steps

Move from the code to a diagnosis path, then into repair pricing once the fault is confirmed.