P0389 critical

Crankshaft Position Sensor B Circuit Intermittent

The P0389 code means the vehicle's onboard diagnostic system has detected: Crankshaft Position Sensor B Circuit Intermittent. This is a critical severity code.

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Keep driving?
No -- stop driving
DIY difficulty
moderate
Estimated cost
$80 - $400 (parts and labor)
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Common Symptoms

  • Intermittent stalling
  • Check Engine Light on
  • Random no-start
  • Engine hesitation

Probable Causes (Ranked by Likelihood)

  • Loose crank sensor B connector Very High
  • Intermittent wire break High
  • Sensor failing under heat Moderate
  • Vibration-induced fault Low

Step-by-Step Diagnostic Procedure

  1. Monitor sensor B signal while performing wiggle test.

  2. Check connector pins for looseness.

  3. Inspect wiring at stress points.

  4. Test sensor during hot and cold conditions.

Frequently Asked Questions

Why does the engine stall randomly?

An intermittent crank sensor signal causes momentary loss of engine position data, which can stall the engine.

Can heat cause P0389?

Yes, heat soak failure is common with crank sensors. The sensor may work cold and fail when hot.

How do I catch the intermittent fault?

Drive with a scan tool recording data. Look for momentary signal dropouts from sensor B.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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