AutoCodes – Generic – B2797

B2797 Code - Communication Malfunction No. 1 Immobilizer System

Quick Answer

This Diagnostic Trouble Code (DTC) is output when a communication error occurs between the key slot and transponder key ECU. 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: B2797 indicates Communication Malfunction No. 1 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 4,527

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 Jan 16, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2797 Description

This Diagnostic Trouble Code (DTC) is output when a communication error occurs between the key slot and transponder key ECU. The DTC B2797 is stored when a key with a BCC malfunction is inserted into the ignition key cylinder.

OBDII Code B2797 - Communication Malfunction No. 1 Immobilizer System - AutoCodes.com — B2797 Code - Communication Malfunction No. 1 Immobilizer System

What does this mean?

What are the Possible Causes of the DTC B2797?

Faulty Key
Faulty Transponder Key Coil
Faulty Transponder Key ECU Assembly

How to Fix the DTC B2797?

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 B2797 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 B2797 code?

Need more information on how to fix the B2797 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B2797 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B2797 Lexus — Communication Malfunction No. 1 Immobilizer System
B2797 Scion — Communication Malfunction No. 1 Immobilizer System
B2797 Toyota — Communication Malfunction No. 1 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 B2797 Code

1. What does the OBDII code B2797 mean?

B2797 indicates a communication malfunction in the immobilizer system, specifically between the Engine Control Module (ECM) and the immobilizer system's components.

2. What are the common symptoms of code B2797?

Symptoms may include the engine failing to start, the security or immobilizer warning light staying on, or difficulty programming new keys.

3. What causes the B2797 code to appear?

Common causes include a faulty key, damaged wiring or connectors in the immobilizer system, a malfunctioning ECM, or a defective immobilizer control module.

4. How do I diagnose the B2797 code?

Diagnosis typically involves checking the immobilizer system wiring and connectors for damage, testing the key, and verifying communication between the ECM and the immobilizer module.

5. Can a dead battery cause the B2797 code?

Yes, a dead or weak battery can disrupt communication in the immobilizer system, potentially triggering the B2797 code.

6. How do I fix the B2797 communication malfunction?

Repairs may include replacing damaged wiring, reprogramming or replacing the key, or repairing/replacing the immobilizer control module or ECM.

7. Can I clear the B2797 code without repairing the problem?

Clearing the code without addressing the underlying issue is not recommended, as the problem will likely recur and prevent the engine from starting.

8. Is it safe to drive with the B2797 code?

No, since this code often prevents the engine from starting, the vehicle may not be drivable until the issue is resolved.

9. Do I need to replace the key if code B2797 appears?

Not always. The key should be tested first to confirm if itâ€™s the source of the issue before replacement.

10. Can a software update fix the B2797 code?

In some cases, a software update for the ECM or immobilizer module may resolve communication issues, but this depends on the specific vehicle model and circumstances.