AutoCodes – GMC – B3935 2016 GMC Sierra

B3935 2016 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 2016 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 230

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 Jun 17, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3935 2016 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 2016 GMC Sierra - Transponder Authentication - AutoCodes.com — B3935 2016 GMC Sierra Code - Transponder Authentication

What does this mean?

What are the Possible Causes of the DTC B3935 2016 GMC Sierra?

Faulty Key/Transmitter
Faulty Body Control Module (BCM)

How to Fix the DTC B3935 2016 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 2016 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 2016 GMC Sierra code?

Need more information on how to fix the B3935 2016 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 2016 GMC Sierra Code

1. What does OBDII code B3935 on a 2016 GMC Sierra indicate?

The B3935 code specifically relates to Transponder Authentication issues in the vehicle's system.

2. What are common symptoms of OBDII code B3935 in a 2016 GMC Sierra?

Common symptoms include issues with starting the vehicle, intermittent stalling, or the vehicle failing to recognize the key fob.

3. What are potential causes of OBDII code B3935 in a 2016 GMC Sierra?

The code may be triggered by a faulty ignition key, a defective transponder, a damaged key fob, or issues with the vehicle's immobilizer system.

4. How can I diagnose OBDII code B3935 in my 2016 GMC Sierra?

Diagnosing the code typically involves using a diagnostic scan tool to retrieve the specific error code and checking the key fob's battery and functionality.

5. Can I repair OBDII code B3935 in my 2016 GMC Sierra myself?

If the issue is related to a faulty key fob battery, you may be able to replace it yourself. However, more complex issues with the transponder or immobilizer system may require professional diagnosis and repair.

6. Will driving with OBDII code B3935 on my 2016 GMC Sierra cause further damage?

Continued driving with this code may lead to persistent starting problems or potential immobilization of the vehicle, so it's best to address the issue promptly.

7. How much does it typically cost to repair OBDII code B3935 in a 2016 GMC Sierra?

The cost of repair can vary depending on the root cause of the issue. Simple fixes like replacing a key fob battery may be relatively inexpensive, while more complex repairs involving the transponder or immobilizer system could be costlier.

8. Can resetting the OBDII system clear the B3935 code in my 2016 GMC Sierra?

Resetting the system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear.

9. How can I prevent OBDII code B3935 from occurring in my 2016 GMC Sierra?

Regularly checking the functionality of your key fob, replacing batteries when needed, and ensuring proper maintenance of the vehicle's immobilizer system can help prevent this code from appearing.