AutoCodes – Generic – B1491

B1491 Code - Ignition Cylinder Sensor Circuit Failure

Quick Answer

The Body Control Module (BCM) monitors the Ignition Cylinder Sensor. Common causes include Faulty Ignition Cylinder Sensor, Ignition Cylinder Sensor harness is open or shorted, Ignition Cylinder Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1491 indicates Ignition Cylinder Sensor Circuit Failure.
Common causes: Common causes include Faulty Ignition Cylinder Sensor, Ignition Cylinder Sensor harness is open or shorted, Ignition Cylinder Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 8,576

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 14, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1491 Description

The Body Control Module (BCM) monitors the Ignition Cylinder Sensor. The BCM sets the OBDII code when the Ignition Cylinder Sensor is not to factory specifications.

OBDII Code B1491 - Ignition Cylinder Sensor Circuit Failure - AutoCodes.com — B1491 Code - Ignition Cylinder Sensor Circuit Failure

What does this mean?

What are the Possible Causes of the DTC B1491?

Faulty Ignition Cylinder Sensor
Ignition Cylinder Sensor harness is open or shorted
Ignition Cylinder Sensor circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B1491?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1491 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1491 code?

Need more information on how to fix the B1491 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1491 code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1491 Code

1. What are the common symptoms of OBDII code B1491 (Ignition Cylinder Sensor Circuit Failure)?

- Common symptoms include difficulty starting the vehicle, ignition key not turning smoothly, and the engine stalling unexpectedly.

2. What are the possible causes of OBDII code B1491?

- The code B1491 can be triggered by a faulty ignition cylinder sensor, damaged wiring in the sensor circuit, or a malfunctioning ignition switch.

3. How can I diagnose the issue causing OBDII code B1491?

- Diagnosing the issue typically involves checking the condition of the ignition cylinder sensor, inspecting the sensor circuit for any damage, and testing the functionality of the ignition switch.

4. Can I still drive my vehicle with OBDII code B1491 present?

- It is not recommended to drive the vehicle with OBDII code B1491 present, as it can lead to potential safety hazards and further damage to the ignition system.

5. How can I repair OBDII code B1491 (Ignition Cylinder Sensor Circuit Failure)?

- Repairing the issue may involve replacing the faulty ignition cylinder sensor, repairing any damaged wiring in the sensor circuit, or replacing the ignition switch if necessary.

6. Is it possible to reset OBDII code B1491 without fixing the underlying issue?

- While you can reset the code using an OBDII scanner, it is crucial to address the root cause of the problem to prevent the code from reappearing.

7. Are there any DIY tips for troubleshooting OBDII code B1491?

- DIY tips include visually inspecting the ignition cylinder sensor, checking for loose or damaged wires in the sensor circuit, and ensuring the ignition switch is functioning correctly.

8. Can a professional mechanic help with diagnosing and repairing OBDII code B1491?

- Yes, a certified mechanic can assist in accurately diagnosing the issue causing the code and performing the necessary repairs to fix the Ignition Cylinder Sensor Circuit Failure.

9. How long does it typically take to repair OBDII code B1491?

- The repair time can vary depending on the extent of the issue, but it may take anywhere from 1 to 3 hours to diagnose and fix the Ignition Cylinder Sensor Circuit Failure.

10. What happens if OBDII code B1491 is ignored?

- Ignoring OBDII code B1491 can lead to potential safety risks, such as the vehicle not starting or stalling unexpectedly, and may cause further damage to the ignition system if left unresolved.