B3935 2017 GMC Sierra Code - Transponder Authentication
Quick Answer
The B3935 diagnostic trouble code (DTC) for a 2017 GMC Sierra relates to an issue with transponder authentication. Common causes include Faulty transponder key, Malfunctioning immobilizer system, Wiring or connection issues between the transponder and immobilizer. 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 2017 GMC Sierra indicates Transponder Authentication.
- Common causes
- Common causes include Faulty transponder key, Malfunctioning immobilizer system, Wiring or connection issues between the transponder and immobilizer.
- 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 B3935 2017 GMC Sierra Description
The B3935 diagnostic trouble code (DTC) for a 2017 GMC Sierra relates to an issue with transponder authentication. In modern vehicles, transponders are small electronic devices embedded in key fobs or ignition keys that communicate with the vehicle's immobilizer system. The transponder sends a unique code to the vehicle's immobilizer system, which then verifies the code to allow the engine to start. If the transponder authentication process fails, the vehicle's engine may not start, or it may start and then immediately shut off.
Common Causes of B3935 2017 GMC Sierra
- Faulty transponder key
- Malfunctioning immobilizer system
- Wiring or connection issues between the transponder and immobilizer
- Low battery in the key fob
- Interference from other electronic devices
Symptoms of B3935 2017 GMC Sierra
- Engine cranks but does not start
- Engine starts but immediately shuts off
- Key fob not recognized by the vehicle
- Security light flashing on the dashboard
- Immobilizer warning message on the instrument cluster
How to Fix B3935 2017 GMC Sierra
- Check the battery in the key fob and replace if necessary.
- Attempt to reprogram the transponder key to the vehicle's immobilizer system.
- Inspect the wiring and connections between the transponder and immobilizer for any damage or loose connections.
- If the issue persists, replace the transponder key or repair/replace the immobilizer system.
- Clear the DTC from the vehicle's computer using a diagnostic scan tool.
Cost to Fix B3935 2017 GMC Sierra
The cost of repairing a transponder authentication issue can vary depending on the specific cause of the problem. Replacing a key fob battery is relatively inexpensive, while reprogramming a transponder key or replacing the key itself can be more costly. On average, the total repair cost for this issue can range from $100 to $500, including parts and labor. However, it's important to note that labor rates at auto repair shops can vary, so it's recommended to check with local shops for a more accurate estimate.
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Frequently Asked Questions about B3935 2017 GMC Sierra Code
1. What does the OBDII code B3935 mean on a 2017 GMC Sierra?
The code B3935 indicates an issue with the Transponder Authentication system, which is responsible for verifying the key's security code during engine start.
2. What are the common symptoms of the B3935 code on a GMC Sierra?
Symptoms may include the engine not starting, security light illumination on the dashboard, or intermittent starting issues.
3. What causes the B3935 code to appear?
Common causes include a malfunctioning transponder key, a damaged ignition switch, wiring issues, or a fault in the vehicle's theft deterrent module.
4. Can I still drive my GMC Sierra with the B3935 code?
If the engine starts, you can drive the vehicle, but the issue may worsen over time. It's best to address it promptly to avoid being locked out of starting your vehicle.
5. How can I fix the B3935 code on my 2017 GMC Sierra?
Repairs might involve reprogramming or replacing the transponder key, inspecting and repairing wiring connections, or replacing the theft deterrent module.
6. How do I know if my transponder key is faulty for the B3935 code?
If you use a spare key and the issue resolves, the original transponder key may be faulty and require replacement or reprogramming.
7. Can a dead key fob battery cause the B3935 code?
No, a dead key fob battery typically won't trigger the B3935 code because it relates to the transponder chip, not the remote functions.
8. How much does it cost to fix the B3935 code on a GMC Sierra?
The cost depends on the exact issue, but replacing or reprogramming a key may cost $50-$300, while module repairs could range from $200-$800.
9. Do I need a professional to fix the B3935 code?
Yes, diagnosing and fixing this code often requires specialized equipment to reprogram keys or diagnose the theft deterrent system.
10. Can disconnecting the battery clear the B3935 code?
No, disconnecting the battery won't solve the underlying issue. The code will likely return unless the root cause is addressed.
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