AutoCodes – Saturn – B3935 Saturn

B3935 Saturn 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 Saturn 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 739

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 Saturn 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 Saturn - Transponder Authentication - AutoCodes.com — B3935 Saturn Code - Transponder Authentication

What does this mean?

What are the Possible Causes of the DTC B3935 Saturn?

Faulty Key/Transmitter
Faulty Body Control Module (BCM)

How to Fix the DTC B3935 Saturn?

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 Saturn 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 Saturn code?

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

Need Help with the Code?

Get the B3935 Saturn 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 B3935 Saturn Code

1. What is OBDII code B3935 Saturn related to Transponder Authentication?

- OBDII code B3935 Saturn indicates a problem with the transponder authentication system, which is a security feature that allows the vehicle to start only when a recognized key is used.

2. What are common symptoms of OBDII code B3935 Saturn?

- Common symptoms of OBDII code B3935 Saturn may include difficulty starting the vehicle, the engine not turning over, or the security light staying illuminated on the dashboard.

3. What are possible causes of OBDII code B3935 Saturn?

- Possible causes of OBDII code B3935 Saturn include a faulty transponder key, a damaged transponder antenna, issues with the transponder module, or problems with the immobilizer system.

4. How can I diagnose OBDII code B3935 Saturn?

- Diagnosing OBDII code B3935 Saturn typically involves using a diagnostic scanner to retrieve the code, checking the transponder key for damage, inspecting the transponder antenna, and testing the transponder module and immobilizer system.

5. Can I repair OBDII code B3935 Saturn myself?

- Repairing OBDII code B3935 Saturn may require specialized tools and knowledge, so it is recommended to consult with a professional automotive technician to accurately diagnose and fix the issue.

6. How much does it cost to repair OBDII code B3935 Saturn?

- The cost to repair OBDII code B3935 Saturn can vary depending on the specific cause of the issue. It is best to get a diagnostic assessment from a qualified mechanic to determine the exact cost of repairs.

7. What happens if I ignore OBDII code B3935 Saturn?

- Ignoring OBDII code B3935 Saturn may lead to continued difficulties starting your vehicle and potential security concerns. It is advisable to address this issue promptly to ensure the proper functioning of the transponder authentication system.

8. Can OBDII code B3935 Saturn cause other problems in my Saturn?

- OBDII code B3935 Saturn specifically relates to transponder authentication, so if left unresolved, it may not directly cause other problems in your Saturn. However, it can impact the vehicle's ability to start and run smoothly.

9. How long does it take to repair OBDII code B3935 Saturn?

- The repair time for OBDII code B3935 Saturn can vary depending on the exact cause of the issue and the complexity of the repair. Some repairs may be quick, while others may require more time for diagnosis and parts replacement.

10. Can OBDII code B3935 Saturn be intermittent?

- Yes, OBDII code B3935 Saturn can be intermittent, meaning the issue may come and go. It is essential to address intermittent issues promptly as they can worsen over time if left unresolved.