AutoCodes – Toyota – B278A 2014 Toyota RAV4

B278A 2014 Toyota RAV4 Code - Short to GND in Immobiliser System Power Source Circuit

Quick Answer

When there is a short to GND in the power supply for the Transponder Key Amplifier of the Engine Switch, the Certification ECU (Smart Key ECU Assembly) stores this Diagnostic Trouble Code (DTC). Common causes include Faulty Engine Switch, Engine Switch harness is open or shorted, Engine Switch circuit 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: B278A 2014 Toyota RAV4 indicates Short to GND in Immobiliser System Power Source Circuit.
Common causes: Common causes include Faulty Engine Switch, Engine Switch harness is open or shorted, Engine Switch circuit 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 254

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jan 16, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B278A 2014 Toyota RAV4 Description

When there is a short to GND in the power supply for the Transponder Key Amplifier of the Engine Switch, the Certification ECU (Smart Key ECU Assembly) stores this Diagnostic Trouble Code (DTC).

OBDII Code B278A 2014 Toyota RAV4 - Short to GND in Immobiliser System Power Source Circuit - AutoCodes.com — B278A 2014 Toyota RAV4 Code - Short to GND in Immobiliser System Power Source Circuit

What does this mean?

What are the Possible Causes of the DTC B278A 2014 Toyota RAV4?

Faulty Engine Switch
Engine Switch harness is open or shorted
Engine Switch circuit electrical connection
Faulty Certification ECU (Smart Key ECU Assembly)

How to Fix the DTC B278A 2014 Toyota RAV4?

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 B278A 2014 Toyota RAV4 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 B278A 2014 Toyota RAV4 code?

Need more information on how to fix the B278A 2014 Toyota RAV4 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B278A 2014 Toyota RAV4 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 B278A 2014 Toyota RAV4 Code

1. What are the common symptoms of OBDII code B278A in a 2014 Toyota RAV4?

- Common symptoms include starting issues, inability to turn over the engine, and the immobilizer system not recognizing the key.

2. What does the OBDII code B278A "Short to GND in Immobiliser System Power Source Circuit" mean in a 2014 Toyota RAV4?

- This code indicates a short to ground in the power source circuit of the immobilizer system, which can prevent the vehicle from starting.

3. What are the possible causes of OBDII code B278A in a 2014 Toyota RAV4?

- Possible causes include damaged wiring in the immobilizer system, faulty immobilizer control module, or a short circuit in the power source circuit.

4. How can I diagnose and repair OBDII code B278A in my 2014 Toyota RAV4?

- To diagnose this code, you may need to perform a thorough inspection of the immobilizer system wiring and components. Repair involves fixing any damaged wiring, replacing faulty components, and clearing the code.

5. Can I still drive my 2014 Toyota RAV4 with OBDII code B278A present?

- It's not recommended to drive the vehicle with this code active, as it can lead to starting issues and potential immobilizer system malfunctions.

6. Is it safe to reset the OBDII code B278A in my 2014 Toyota RAV4 using a diagnostic tool?

- You can attempt to clear the code using a diagnostic tool, but it's important to address the underlying issue causing the code to prevent further starting problems.

7. How much does it typically cost to repair OBDII code B278A in a 2014 Toyota RAV4?

- The cost of repair can vary depending on the specific cause of the code and whether any components need to be replaced. It's advisable to consult a professional for an accurate estimate.

8. Can a DIY enthusiast fix OBDII code B278A in a 2014 Toyota RAV4?

- While some aspects of diagnosing and repairing this code may be within reach of a skilled DIY enthusiast, it's recommended to seek professional help to ensure proper diagnosis and repair.

9. Will OBDII code B278A cause permanent damage to my 2014 Toyota RAV4 if not addressed promptly?

- Ignoring this code can lead to starting issues and potential immobilizer system malfunctions, so it's best to address it promptly to prevent further problems.

10. How can I prevent OBDII code B278A from occurring in my 2014 Toyota RAV4 in the future?

- Regular maintenance, checking the condition of wiring and components in the immobilizer system, and addressing any issues promptly can help prevent the recurrence of this code.