AutoCodes – GMC – B3935 2014 GMC Sierra

B3935 2014 GMC Sierra Code - Transponder Authentication

Quick Answer

When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the key is energized by the exciter coil surrounding the ignition lock cylinder. Common causes include Faulty Key/Transmitter, Faulty Body Control Module (BCM). 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: B3935 2014 GMC Sierra indicates Transponder Authentication.
Common causes: Common causes include Faulty Key/Transmitter, Faulty Body Control Module (BCM).
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 206

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jun 17, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3935 2014 GMC Sierra Description

When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the key is energized by the exciter coil surrounding the ignition lock cylinder. The transponder transmits a signal to the immobilizer control module. The immobilizer control module translates this signal to a serial data message which is sent to the Body Control Module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the Engine Control Module (ECM) If the learned key code does not match or a transponder value is not received, the BCM will send the start disable password to the ECM.

OBDII Code B3935 2014 GMC Sierra - Transponder Authentication - AutoCodes.com — B3935 2014 GMC Sierra Code - Transponder Authentication

What does this mean?

What are the Possible Causes of the DTC B3935 2014 GMC Sierra?

Faulty Key/Transmitter
Faulty Body Control Module (BCM)

How to Fix the DTC B3935 2014 GMC Sierra?

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 B3935 2014 GMC Sierra 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 B3935 2014 GMC Sierra code?

Need more information on how to fix the B3935 2014 GMC Sierra code? Get Access to Factory Service Manuals

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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 B3935 2014 GMC Sierra Code

1. What does OBDII code B3935 mean on a 2014 GMC Sierra?

Code B3935 indicates an issue with the transponder authentication system, which involves communication between the vehicle's key or key fob and the theft deterrent module.

2. What are the common symptoms of code B3935 in a 2014 GMC Sierra?

Symptoms may include the engine not starting, the security light staying illuminated on the dash, or intermittent starting issues.

3. What causes code B3935 to appear on a 2014 GMC Sierra?

Common causes include a faulty key or key fob, issues with the theft deterrent control module, damaged wiring, or an incorrect key being used.

4. How can I diagnose code B3935 on my 2014 GMC Sierra?

Start by checking the key or key fob for damage or battery issues, then inspect the wiring and connections to the theft deterrent module. A diagnostic scan tool can also check for related codes.

5. Can a weak key fob battery trigger code B3935?

Yes, a weak or dead key fob battery can cause communication issues with the transponder, potentially triggering this code.

6. Is it safe to drive with code B3935 active in my 2014 GMC Sierra?

No, this code typically prevents the vehicle from starting, so driving is not possible until the issue is resolved.

7. How do I fix code B3935 on my 2014 GMC Sierra?

Fixes may include replacing the key or key fob, reprogramming the theft deterrent module, repairing damaged wiring, or replacing a faulty module.

8. Can code B3935 be cleared without making repairs?

Clearing the code with a scan tool may temporarily reset it, but the issue will likely return unless the underlying problem is resolved.

9. How much does it cost to repair code B3935 on a 2014 GMC Sierra?

Repair costs vary but may include $50â€“$200 for a new key or fob, $100â€“$300 for reprogramming, and additional costs if the theft deterrent module or wiring needs repair.

10. Do I need to reprogram the key fob after fixing code B3935?

Yes, in many cases, reprogramming the key fob or theft deterrent system is necessary to ensure proper communication and resolve the code.