AutoCodes – Generic – B2478

B2478 Code - Anti-Theft Input Signal Short To Ground

Quick Answer

The Body Control Module (BCM) monitors the Anti-Theft Input Signal. Common causes include Faulty Anti-Theft System, Anti-Theft System harness is open or shorted, Anti-Theft System circuit poor electrical connection. 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: B2478 indicates Anti-Theft Input Signal Short To Ground.
Common causes: Common causes include Faulty Anti-Theft System, Anti-Theft System harness is open or shorted, Anti-Theft System circuit poor electrical connection.
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 3,465

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 Dec 09, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2478 Description

The Body Control Module (BCM) monitors the Anti-Theft Input Signal. The BCM sets the OBDII code when the Anti-Theft Input Signal is not to factory specifications.

OBDII Code B2478 - Anti-Theft Input Signal Short To Ground - AutoCodes.com — B2478 Code - Anti-Theft Input Signal Short To Ground

What does this mean?

What are the Possible Causes of the DTC B2478?

Faulty Anti-Theft System
Anti-Theft System harness is open or shorted
Anti-Theft System circuit poor electrical connection

How to Fix the DTC B2478?

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 B2478 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 B2478 code?

Need more information on how to fix the B2478 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B2478 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B2478 Buick — Reverse Light Relay Shorted To Battery
B2478 Cadillac — Reverse Light Relay Shorted To Battery
B2478 Chevrolet — Reverse Light Relay Shorted To Battery
B2478 GMC — Reverse Light Relay Shorted To Battery

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 B2478 Code

1. What are the common symptoms of OBDII code B2478 (Anti-Theft Input Signal Short To Ground)?

The common symptoms include the vehicle not starting, the security light staying on, and the key fob not working.

2. What are the possible causes of OBDII code B2478?

Possible causes include a short to ground in the anti-theft input signal circuit, a faulty anti-theft module, damaged wiring, or a defective key fob.

3. How can I diagnose OBDII code B2478?

Diagnosing this code typically involves checking the anti-theft system components for damage, testing the wiring for shorts, and inspecting the key fob for faults.

4. What are some repair tips for OBDII code B2478?

Repair tips include checking and repairing any damaged wiring, replacing a faulty anti-theft module, reprogramming key fobs, and ensuring all connections are secure.

5. Can OBDII code B2478 be fixed without professional help?

Depending on your experience and tools available, you may be able to fix this code yourself by following diagnostic procedures and making necessary repairs.

6. How serious is OBDII code B2478?

While this code may not directly affect the drivability of the vehicle, it can cause inconvenience by preventing the vehicle from starting or affecting the anti-theft system.

7. Can OBDII code B2478 cause other issues in the vehicle?

If left unresolved, this code may lead to further problems with the anti-theft system, potentially affecting the vehicle's security.

8. Is it safe to continue driving with OBDII code B2478 present?

It is not recommended to drive the vehicle with this code present, as it may result in the vehicle not starting or other anti-theft system issues.

9. How much does it typically cost to repair OBDII code B2478?

The cost of repairing this code can vary depending on the extent of the issue, the parts needed, and whether professional labor is required.

10. How can I prevent OBDII code B2478 from occurring again?

To prevent this code from recurring, it's essential to maintain the anti-theft system components, avoid damaging wiring during repairs or maintenance, and keep key fobs in good working condition.