P0389 high Severity

P0389: Crankshaft Position Sensor B Circuit Intermittent

Potential no‑start condition, rough idle, stalling and loss of power due to intermittent crankshaft position data affecting ignition timing and fuel delivery

Overview

P0389 indicates an intermittent or erratic signal from the secondary crankshaft position (CKP) sensor B circuit, affecting engine timing and performance

Common Symptoms

  • Check Engine Light illuminated intermittently or steadily
  • Engine may not start or hard to start
  • Intermittent stalling or rough idle
  • Hesitation or lack of power during acceleration
  • Tachometer not registering RPM during crank

Most Common Causes

Faulty crankshaft position sensor B high

Sensor internal wear, contamination, or heat damage causing intermittent signal outputs

Damaged or corroded wiring/connectors to CKP sensor B high

Open, shorted, or poor connections can disrupt signal to PCM

Loose or poor electrical connections at sensor or harness medium

Intermittent contact can mimic sensor failure

PCM/ECM internal fault or software error low

Rare but possible if all other circuitry tests good

Diagnostic Steps

  1. Connect OBD‑II scanner and read stored codes including freeze‑frame data
    Expected: Presence of P0389 and related codes
    Interpretation: Confirm intermittent crankshaft position sensor B circuit fault
  2. Perform a visual inspection of sensor B wiring and connectors
    Expected: Check for damage, corrosion, oil or fluid contamination
    Interpretation: Wiring damage or poor connector condition supports circuit fault
  3. Measure voltage and resistance at CKP sensor B with multimeter/oscilloscope
    Expected: Stable reference, signal, and ground according to manufacturer specs
    Interpretation: Intermittent or no signal confirms sensor or wiring fault
  4. Check continuity of wiring harness from sensor to PCM
    Expected: Continuous circuit with proper resistance
    Interpretation: Open/shorted circuits indicate harness repair requirement
  5. If wiring and sensor check good, evaluate PCM input circuit and consider reprogramming
    Expected: Proper reception of test signal at PCM input
    Interpretation: Failure indicates possible PCM internal issue

Repair Solutions

Replace crankshaft position sensor B medium
Estimated Cost: $100 - $300

Typical part and labor range; cost varies by vehicle

Repair or replace damaged wiring/connectors medium
Estimated Cost: $50 - $200

Depends on extent of wiring harness damage

Clean and secure sensor connectors easy
Estimated Cost: $10 - $50

Quick fix if corrosion or contamination is present

Reprogram or replace PCM/ECM hard
Estimated Cost: $200 - $1000

Consider only after all sensor and wiring tests clear

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Misinterpreting intermittent wiring fault as sensor failure
  • Attributing symptoms solely to fuel or ignition issues unrelated to crankshaft sensor
  • Assuming secondary camshaft sensor fault instead of CKP sensor B

Frequently Asked Questions

What does the P0389 code mean?

Technically, the P0389 code represents Crankshaft Position Sensor B Circuit Intermittent. It usually points to a fault within the Ignition.

Can P0389 cause engine damage?

You should treat P0389 as a high issue. Potential no‑start condition, rough idle, stalling and loss of power due to intermittent crankshaft position data affecting ignition timing and fuel delivery

Common signs of the P0389 error code

Common symptoms include: Check Engine Light illuminated intermittently or steadily, Engine may not start or hard to start, Intermittent stalling or rough idle. You might also notice the Check Engine Light is on.

Common triggers for the P0389 error

It can be caused by several factors, most notably: Faulty crankshaft position sensor B, Damaged or corroded wiring/connectors to CKP sensor B, Loose or poor electrical connections at sensor or harness.

Estimated repair costs for different causes of P0389

The cost varies significantly based on the root cause. For example, replacing a Clean and secure sensor connectors typically costs between $10 and $50, while fixing a Reprogram or replace PCM/ECM can range from $200 to $1000.

Does P0389 affect Ford, Toyota, or Honda?

This is a universal code. You might see P0389 on Ford, Chevrolet, Toyota, Honda, Nissan, or any other OBD-II vehicle.

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