OBD Guide
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U1401

Implausible Engine Speed Signal Received

U1401 is an OBD-II diagnostic trouble code meaning: Implausible Engine Speed Signal Received. Common causes: malfunction of the crankshaft position sensor, open or short circuit in the sensor circuit. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Unstable engine idling
  • Dips during acceleration
  • Difficulty starting the engine
  • Increased fuel consumption
  • Check Engine Light Is On

Causes

  • Malfunction of the crankshaft position sensor
  • Open or short circuit in the sensor circuit
  • Damage to the ring gear on the flywheel
  • Interference in the electrical system
  • ECM problems

How to Fix

  1. Check the condition of the crankshaft sensor and its wiring
  2. Check resistance and sensor signal
  3. Inspect the ring gear on the flywheel
  4. Check ECM for errors
  5. Replace faulty components

Related codes

U1400U1402P0335

FAQ

What does the U1401 code mean?

U1401 is an OBD-II diagnostic trouble code that indicates: Implausible Engine Speed Signal Received

What causes a U1401 error code?

The most common causes of U1401 include: Malfunction of the crankshaft position sensor; Open or short circuit in the sensor circuit; Damage to the ring gear on the flywheel; Interference in the electrical system.

How do I fix a U1401 diagnostic trouble code?

To fix U1401: Check the condition of the crankshaft sensor and its wiring. Check resistance and sensor signal. Inspect the ring gear on the flywheel. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1401?

Limited driving only, diagnose soon

How much does it cost to fix U1401?

The estimated repair cost for U1401 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat