AutoCodes – Toyota – B279A 2017 Toyota RAV4

B279A 2017 Toyota RAV4 Code - Theft Deterrent System Communication Line High Fixation

Quick Answer

The Diagnostic Trouble Code (DTC) will be set in the Engine Control Module (ECM) when the communication line (IMI - EFIO) between the Engine Control Module and the Certification ECU (Smart Key ECU Assembly) is stuck high. Common causes include Faulty Certification ECU (Smart Key ECU Assembly), Certification ECU harness is open or shorted, Certification ECU 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
B279A 2017 Toyota RAV4 indicates Theft Deterrent System Communication Line High Fixation.
Common causes
Common causes include Faulty Certification ECU (Smart Key ECU Assembly), Certification ECU harness is open or shorted, Certification ECU 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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 528
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jan 17, 2023
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Code B279A 2017 Toyota RAV4 Description

The Diagnostic Trouble Code (DTC) will be set in the Engine Control Module (ECM) when the communication line (IMI - EFIO) between the Engine Control Module and the Certification ECU (Smart Key ECU Assembly) is stuck high.
OBDII Code B279A 2017 Toyota RAV4 - Theft Deterrent System Communication Line High Fixation - AutoCodes.com
B279A 2017 Toyota RAV4 Code - Theft Deterrent System Communication Line High Fixation

What are the Possible Causes of the DTC B279A 2017 Toyota RAV4?

  • Faulty Certification ECU (Smart Key ECU Assembly)
  • Certification ECU harness is open or shorted
  • Certification ECU circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC B279A 2017 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 B279A 2017 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 B279A 2017 Toyota RAV4 code?

Need more information on how to fix the B279A 2017 Toyota RAV4 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B279A 2017 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 B279A 2017 Toyota RAV4 Code

1. What does OBDII code B279A mean in a 2017 Toyota RAV4?

Code B279A indicates an issue with the Theft Deterrent System Communication Line, specifically a "High Fixation" error, which means the communication signal is abnormal or out of range.

2. What are the common symptoms of code B279A in a 2017 Toyota RAV4?

Symptoms may include the engine failing to start, the security light staying on or flashing, or the vehicle being unable to recognize the key.

3. What causes the B279A code in a 2017 Toyota RAV4?

This code is often caused by a faulty key, malfunctioning immobilizer system, damaged wiring in the communication circuit, or an issue with the Engine Control Module (ECM).

4. Can a weak or dead key fob battery trigger the B279A code?

Yes, a weak or dead key fob battery can disrupt communication between the key and the Theft Deterrent System, potentially triggering this code.

5. How can I fix code B279A on my 2017 Toyota RAV4?

Start by checking the key fob battery and replacing it if necessary. Inspect the wiring and connectors in the immobilizer system for damage or corrosion. If the issue persists, a professional diagnosis may be needed to test the ECM or immobilizer.

6. Is it safe to drive with the B279A code active?

No, the B279A code often prevents the engine from starting, so the vehicle will likely be inoperable until the issue is resolved.

7. How much does it typically cost to fix the B279A code on a 2017 Toyota RAV4?

Repair costs can vary but typically range from $100 to $500, depending on whether the issue is a simple fix like replacing a key fob battery or a more complex repair involving the immobilizer or ECM.

8. Can a DIYer fix the B279A code on a 2017 Toyota RAV4?

Basic fixes, like replacing the key fob battery or inspecting wiring, can be done by a DIYer. However, advanced diagnostics and repairs involving the immobilizer or ECM should be handled by a professional.

9. Does the B279A code always mean a faulty immobilizer system?

Not always. While a faulty immobilizer is a common cause, the issue could also stem from wiring problems, a defective key, or ECM malfunctions.

10. Can a locksmith help resolve a B279A code on a 2017 Toyota RAV4?

Yes, an automotive locksmith can often diagnose and fix key-related issues, including reprogramming or replacing a faulty key, which may resolve the B279A code.

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