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B3902 2017 GMC Sierra Code - Incorrect Immobilizer Identifier Received

Quick Answer

The B3902 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates that an incorrect immobilizer identifier has been received. Common causes include Faulty key fob or key transponder, Wiring issues in the immobilizer system, ECM malfunction. 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
B3902 2017 GMC Sierra indicates Incorrect Immobilizer Identifier Received.
Common causes
Common causes include Faulty key fob or key transponder, Wiring issues in the immobilizer system, ECM malfunction.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 13, 2024
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Code B3902 2017 GMC Sierra Description

The B3902 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates that an incorrect immobilizer identifier has been received. The immobilizer system in a vehicle is designed to prevent unauthorized access and theft by requiring a specific code or identifier to start the engine. When the immobilizer identifier received is incorrect, it means that the vehicle's computer is not recognizing the correct code, which can lead to starting issues or the engine not running at all.

OBDII Code B3902 2017 GMC Sierra - Incorrect Immobilizer Identifier Received
B3902 2017 GMC Sierra Code - Incorrect Immobilizer Identifier Received

Common Causes of B3902 2017 GMC Sierra

  1. Faulty key fob or key transponder.
  2. Wiring issues in the immobilizer system.
  3. ECM malfunction.
  4. Battery voltage issues affecting the immobilizer system.
  5. Aftermarket modifications interfering with the immobilizer system.

Symptoms of B3902 2017 GMC Sierra

  1. Engine cranks but does not start.
  2. Engine starts and then immediately shuts off.
  3. Immobilizer warning light illuminated on the dashboard.
  4. Inability to turn the ignition key.

How to Fix B3902 2017 GMC Sierra

  1. Check and replace the key fob battery: Start by replacing the battery in the key fob to ensure it is transmitting the correct signal.
  2. Check wiring connections: Inspect the wiring connections in the immobilizer system for any loose or damaged wires and repair as needed.
  3. Reset the ECM: Perform a reset on the ECM to clear any stored codes and relearn the immobilizer system.
  4. Reprogram the key fob: If the key fob is not transmitting the correct signal, it may need to be reprogrammed to sync with the vehicle's immobilizer system.
  5. Consult a professional: If the issue persists after these steps, it is recommended to consult a professional automotive technician with experience in immobilizer systems for further diagnosis and repair.

Cost to Fix B3902 2017 GMC Sierra

The typical repair costs for addressing an incorrect immobilizer identifier received code can vary depending on the specific cause of the issue. Replacement key fobs or key transponders can range from $50 to $200, while wiring repairs or ECM resets may cost between $100 and $300. Labor costs at auto repair shops can range from $80 to $150 per hour, and the total repair bill can add up based on the complexity of the diagnosis and repair process. It is advisable to get a detailed estimate from a trusted automotive technician to determine the exact cost for resolving this issue.

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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 B3902 2017 GMC Sierra Code

1. What does the OBDII code B3902 mean on a 2017 GMC Sierra?

The B3902 code indicates that the vehicle’s immobilizer system has detected an incorrect identifier, preventing the engine from starting.

2. What are the common symptoms of the B3902 code in a GMC Sierra?

Symptoms include the engine not starting, the security light staying illuminated or flashing on the dashboard, and possible intermittent starting issues.

3. What causes the B3902 code in a 2017 GMC Sierra?

Common causes include a faulty key fob, a damaged or unprogrammed key, issues with the immobilizer control module, or wiring/connectivity problems in the security system.

4. Can a weak key fob battery cause the B3902 code?

Yes, a weak or dead key fob battery can interfere with proper communication between the key and the immobilizer system, triggering the code.

5. How can I fix the B3902 code on my GMC Sierra?

Start by replacing the key fob battery, ensuring the key is programmed correctly, and checking for any wiring or connection issues in the immobilizer system. If the problem persists, consult a professional.

6. Will clearing the B3902 code make my GMC Sierra start?

Clearing the code alone won’t resolve the issue unless the underlying cause is fixed. The immobilizer system must recognize the correct identifier to allow the engine to start.

7. Do I need to reprogram my key if I see the B3902 code?

If the key has lost its programming or is not recognized by the immobilizer system, reprogramming it may be necessary to resolve the issue.

8. Can a faulty immobilizer module trigger the B3902 code?

Yes, a malfunctioning immobilizer control module can fail to properly identify the key and trigger the B3902 code.

9. How much does it cost to fix a B3902 code on a 2017 GMC Sierra?

Repair costs can vary, but replacing a key fob or reprogramming it may cost $100–$300. If the immobilizer module needs replacement, costs could exceed $500, depending on labor rates.

10. Can a locksmith fix the B3902 code issue?

Yes, a qualified automotive locksmith can often reprogram or replace a key and troubleshoot immobilizer-related issues for less than a dealership.

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