B2799 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 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.
Code B2799 Description
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.
What are the Possible Causes of the DTC B2799?
-
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?
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 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 B2799 code?
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Information for Specific Makes
- B2799 Lexus — Engine Immobiliser System Malfunction
- B2799 Scion — Engine Immobiliser System Malfunction
- B2799 Toyota — Engine Immobiliser System Malfunction
Frequently Asked Questions about B2799 Code
1. What does OBDII code B2799 mean?
B2799 indicates a malfunction in the engine immobilizer system, which is designed to prevent unauthorized vehicle operation by disabling the engine start function.
2. What are the common symptoms of code B2799?
Common symptoms include the engine failing to start, the security or immobilizer light staying on or flashing, and no communication between the key and the immobilizer system.
3. What causes the B2799 code to appear?
Possible causes include a faulty immobilizer control module, damaged or incorrectly programmed key, wiring issues, or problems with the engine control module (ECM).
4. Can a dead key fob battery trigger the B2799 code?
Yes, a dead or weak key fob battery can prevent proper communication between the key and the immobilizer system, which may trigger the code.
5. How can I diagnose the B2799 code?
Diagnose the code by scanning for trouble codes, checking the key and immobilizer system for proper operation, inspecting wiring and connectors, and testing the immobilizer control module.
6. Can I fix the B2799 code myself?
If the issue is a dead key fob battery or a loose connection, you may be able to fix it yourself. For more complex issues like reprogramming keys or replacing the immobilizer module, professional assistance is recommended.
7. Do I need to reprogram the key if I get the B2799 code?
Reprogramming may be necessary if the key has lost synchronization with the immobilizer system or if a new key needs to be paired with the vehicle.
8. How much does it cost to repair a B2799 code?
Repair costs can vary widely, ranging from $50–$100 for a key fob battery replacement to $200–$500 or more for reprogramming, module replacement, or wiring repairs.
9. Can a faulty ECM cause the B2799 code?
Yes, a malfunctioning ECM can fail to communicate properly with the immobilizer system, which may result in the B2799 code.
10. Will clearing the B2799 code solve the problem?
Clearing the code without addressing the underlying issue will not solve the problem, and the code will likely reappear. Proper diagnosis and repair are necessary.
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