AutoCodes – Generic – B2798

B2798 Code - Communication Malfunction No. 2 Immobilizer System

Quick Answer

The Diagnostic Trouble Code (DTC) B2798 is stored when a key is inserted into the ignition key cylinder, but a communication error occurs between the key and Transponder Key ECU Assembly. Common causes include Faulty Key, Faulty Transponder Key Coil, Faulty Transponder Key ECU Assembly. 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: B2798 indicates Communication Malfunction No. 2 Immobilizer System.
Common causes: Common causes include Faulty Key, Faulty Transponder Key Coil, Faulty Transponder Key ECU Assembly.
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 9,276

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 B2798 Description

The Diagnostic Trouble Code (DTC) B2798 is stored when a key is inserted into the ignition key cylinder, but a communication error occurs between the key and Transponder Key ECU Assembly.

OBDII Code B2798 - Communication Malfunction No. 2 Immobilizer System - AutoCodes.com — B2798 Code - Communication Malfunction No. 2 Immobilizer System

What does this mean?

What are the Possible Causes of the DTC B2798?

Faulty Key
Faulty Transponder Key Coil
Faulty Transponder Key ECU Assembly

How to Fix the DTC B2798?

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 B2798 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 B2798 code?

Need more information on how to fix the B2798 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B2798 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B2798 Lexus — Communication Malfunction No. 2 Immobilizer System
B2798 Scion — Communication Malfunction No. 2 Immobilizer System
B2798 Toyota — Communication Malfunction No. 2 Immobilizer System

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 B2798 Code

1. What are the common symptoms of OBDII code B2798 (Communication Malfunction No. 2 Immobilizer System)?

- Common symptoms include difficulty starting the vehicle, engine stalling, and the immobilizer system light staying illuminated.

2. What are the possible causes of OBDII code B2798?

- Causes may include wiring issues, faulty immobilizer system components, a malfunctioning key fob, or a problem with the engine control module (ECM).

3. How can I diagnose the source of OBDII code B2798?

- Diagnosis typically involves checking the wiring connections, inspecting the immobilizer system components, testing the key fob, and scanning the ECM for related error codes.

4. Can OBDII code B2798 be repaired without professional help?

- Some simple repairs, such as checking and fixing loose wiring connections, can be done by DIY enthusiasts. However, for complex issues, it's advisable to seek professional assistance.

5. Is it safe to continue driving with OBDII code B2798 present?

- It is not recommended to drive the vehicle with this code active, as it may lead to starting issues or potential stalling while driving, compromising safety.

6. How much does it typically cost to repair OBDII code B2798?

- Repair costs can vary depending on the underlying issue, but they may range from $100 for minor fixes like wiring repairs to $500 or more for component replacements.

7. Can resetting the ECM clear OBDII code B2798?

- Resetting the ECM may temporarily clear the code, but if the underlying issue persists, the code is likely to reappear once the system detects the problem again.

8. Are there any preventative measures to avoid OBDII code B2798?

- Regular maintenance checks, ensuring proper key fob functionality, and promptly addressing any warning lights related to the immobilizer system can help prevent this code.

9. What role does the immobilizer system play in vehicle security?

- The immobilizer system is designed to prevent unauthorized access to the vehicle by disabling the engine's ignition system unless the correct key or key fob is used.

10. Can a malfunctioning immobilizer system affect other vehicle functions?

- Yes, a malfunctioning immobilizer system can impact the vehicle's overall performance and safety by causing starting issues and potential engine stalling, among other problems.