AutoCodes – Cadillac – B3935 Cadillac

B3935 Cadillac 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 Cadillac 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 2,682

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

What does this mean?

What are the Possible Causes of the DTC B3935 Cadillac?

Faulty Key/Transmitter
Faulty Body Control Module (BCM)

How to Fix the DTC B3935 Cadillac?

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 Cadillac 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 Cadillac code?

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

Need Help with the Code?

Get the B3935 Cadillac 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 Cadillac Code

1. What does OBDII code B3935 in a Cadillac indicate?

The B3935 code typically indicates a transponder authentication error in the vehicle's system.

2. What are some common symptoms of OBDII code B3935 in a Cadillac?

Common symptoms include issues with starting the vehicle, the engine not turning over, or the vehicle going into theft mode.

3. What can cause OBDII code B3935 to trigger in a Cadillac?

The B3935 code may be triggered by problems with the transponder key, faulty transponder antenna, or issues with the security system module.

4. How can I diagnose the cause of OBDII code B3935 in my Cadillac?

Diagnosing the B3935 code typically involves checking the transponder key, inspecting the transponder antenna, and using a diagnostic tool to scan the vehicle's security system.

5. Is it safe to continue driving with OBDII code B3935 in my Cadillac?

It is not recommended to drive the vehicle with the B3935 code present, as it may result in starting or security issues that could leave you stranded.

6. Can I repair OBDII code B3935 in my Cadillac myself?

Repairing the B3935 code may require specialized equipment and knowledge, so it is recommended to have a professional technician diagnose and repair the issue.

7. How much does it cost to fix OBDII code B3935 in a Cadillac?

The cost of fixing the B3935 code can vary depending on the underlying cause and the shop's labor rates. It is advisable to get a few quotes from different mechanics.

8. Are there any preventive measures to avoid OBDII code B3935 in a Cadillac?

Ensuring the transponder key is in good condition, keeping the transponder antenna clean, and following the manufacturer's recommended maintenance schedule can help prevent the B3935 code from appearing.

9. Can a weak car battery trigger OBDII code B3935 in a Cadillac?

A weak car battery can potentially cause issues with the transponder system, leading to the B3935 code being triggered. It's essential to maintain a healthy battery to prevent such problems.

10. Will resetting the OBDII system clear the B3935 code in a Cadillac?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to return. It's important to diagnose and repair the root cause of the problem.