AutoCodes – Scion – B2799 Scion

B2799 Scion Code - Engine Immobiliser System Malfunction

Quick Answer

The Engine Control Module (ECM) stores this Diagnostic Trouble Code (DTC) when the communication line between the ECM and Transponder Key ECU Assembly is malfunctioning, or the communication ID of the ECM and Transponder Key ECU Assembly does not match. Common causes include Without Smart Key, Faulty Transponder Key ECU Assembly, Transponder Key ECU Assembly harness is open or shorted. 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: B2799 Scion indicates Engine Immobiliser System Malfunction.
Common causes: Common causes include Without Smart Key, Faulty Transponder Key ECU Assembly, Transponder Key ECU Assembly harness is open or shorted.
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 20,217

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
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2799 Scion Description

The Engine Control Module (ECM) stores this Diagnostic Trouble Code (DTC) when the communication line between the ECM and Transponder Key ECU Assembly is malfunctioning, or the communication ID of the ECM and Transponder Key ECU Assembly does not match.
For vehicles with Smart Key, this DTC will be set when there are communication malfunctions between the ECM and certification ECU (Smart Key ECU Assembly), or when the communication ID codes do not match, the ECM stores this DTC.
Before troubleshooting this DTC, ensure that no DTC is detected in the transponder key ECU. If there is a key code-related DTC detected in the Transponder Key ECU Assembly or Certification ECU (Smart Key ECU Assembly), repair it first.

OBDII Code B2799 Scion - Engine Immobiliser System Malfunction - AutoCodes.com — B2799 Scion Code - Engine Immobiliser System Malfunction

What does this mean?

What are the Possible Causes of the DTC B2799 Scion?

Without Smart Key

Faulty Transponder Key ECU Assembly
Transponder Key ECU Assembly harness is open or shorted
Transponder Key ECU Assembly circuit poor electrical connection
Faulty Engine Control Module (ECM)
With Smart Key
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 B2799 Scion?

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 B2799 Scion 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.

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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 B2799 Scion Code

What does the OBDII code B2799 mean in a Scion?

Code B2799 indicates a malfunction in the engine immobilizer system, which prevents the engine from starting if the correct key is not detected.

What are common symptoms of code B2799 in a Scion?

Symptoms include the engine failing to start, security warning lights on the dashboard, and potential intermittent starting issues.

What causes code B2799 in a Scion?

Common causes include a faulty transponder key, a damaged immobilizer system antenna, wiring issues, or problems with the engine control module (ECM).

Can a weak car battery trigger code B2799?

Yes, a weak or failing battery can disrupt the immobilizer systemâ€™s operation, potentially leading to this code.

How do I fix code B2799 in a Scion?

Repairs may involve reprogramming or replacing the key, inspecting and repairing wiring, replacing the immobilizer antenna, or addressing ECM issues.

Can I clear code B2799 without fixing the issue?

Clearing the code without addressing the underlying problem may temporarily erase it, but the issue will likely return until the malfunction is resolved.

Will code B2799 prevent my Scion from starting?

Yes, this code can prevent the engine from starting due to immobilizer system failure.

How much does it cost to repair code B2799 in a Scion?

Repair costs vary depending on the issue but can range from $150 for reprogramming a key to over $500 for replacing immobilizer components.

Can code B2799 be caused by a faulty key fob?

Yes, a malfunctioning or improperly programmed key fob can trigger this code and prevent the immobilizer system from functioning correctly.

Do I need a professional to fix code B2799?

While some issues like reprogramming a key may require professional tools, diagnosing and repairing wiring or ECM problems typically requires a qualified technician.