OBD Guide
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B1491

Ignition Cylinder Sensor Circuit Failure

B1491 is an OBD-II diagnostic trouble code meaning: Ignition Cylinder Sensor Circuit Failure. Common causes: open or short circuit in wiring harness, ignition cylinder sensor malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Misfires
  • Unstable engine operation
  • Power reduction
  • Difficulty starting the engine

Causes

  • Open or short circuit in wiring harness
  • Ignition cylinder sensor malfunction
  • Poor contact in connectors
  • ECU malfunction

How to Fix

  1. Check wiring harness for open or short circuit
  2. Check sensor connectors for oxidation or damage.
  3. Replace the ignition cylinder sensor if necessary
  4. Check the operation of the computer

Related codes

P0300P0301P0302P0303P0304

FAQ

What does the B1491 code mean?

B1491 is an OBD-II diagnostic trouble code that indicates: Ignition Cylinder Sensor Circuit Failure

What causes a B1491 error code?

The most common causes of B1491 include: Open or short circuit in wiring harness; Ignition cylinder sensor malfunction; Poor contact in connectors; ECU malfunction.

How do I fix a B1491 diagnostic trouble code?

To fix B1491: Check wiring harness for open or short circuit. Check sensor connectors for oxidation or damage.. Replace the ignition cylinder sensor if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1491?

Limited driving only, diagnose soon

How much does it cost to fix B1491?

The estimated repair cost for B1491 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat