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Ask Skyvisions Your Own Question
Skyvisions
Skyvisions, ASE Certified Technician
Category: Lexus
Satisfied Customers: 14412
Experience:  Lexus Expert
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Lexus GS300: I have a 2006 Lexus GS300 that will not start.

Customer Question

I have a 2006 Lexus GS300 that will not start. The battery died the night before, now it will not start. Code B2799 came on and I don't know how to reset it.
Submitted: 4 years ago.
Category: Lexus
Expert:  Skyvisions replied 4 years ago.
Thank you for choosing JustAnswer and allowing me to help you resolve your Lexus questions! Does the engine crank over normally or does the starter not engage in all? Do you have the smart start key function?
Customer: replied 4 years ago.

The

Customer: replied 4 years ago.

The starter does not crank, I have full power however the starter doesnt crank. Also, I can't lock and unlock the car with the remote.

Expert:  Skyvisions replied 4 years ago.
Even though there's enough power to turn on some of the components have you tried a jumpstart with good jumper cables to the battery? Have you had the battery tested? Do you have a pushbutton start system or a standard ignition key?
Customer: replied 4 years ago.

I gave direct current to the purple starter relay with my power probe. The car turns over fast so I know the battery is good. It has a push start ignition.


 

Expert:  Skyvisions replied 4 years ago.
Do you have another remote start key fobs?
Customer: replied 4 years ago.


Just one key.

Expert:  Skyvisions replied 4 years ago.
When you place your foot on the brake pedal does the light in the start button turn green or does it stay orange or red? If you place the smart start key fobs directly on the start button then use your finger to push the button down holding your foot on the brake does the engine crank over?
Customer: replied 4 years ago.


The light stays green. The engine does not crank over when I push the start button.

Expert:  Skyvisions replied 4 years ago.
If you remove the negative battery cable to erase the memory in the engine control computer does the code go away or does the code stay there when you power the ignition switch on?
Customer: replied 4 years ago.


yes

Expert:  Skyvisions replied 4 years ago.

This means that either the key immobilizer code is not communicating with the immobilizer ECU or the communication line between the immobilizer ECU and the engine control computer is malfunctioning. The weakest link is normally a bad key fob. The only way to know for certain is to use a Lexus scan tool that will communicate with both of these ECUs on the high-speed can network.

Customer: replied 4 years ago.


The car was running yesturday without any problems, I changed the battery because a light was on, is there any way to manually program the key?

Expert:  Skyvisions replied 4 years ago.
Unfortunately no a smart key can only be programmed or added with a scan tool from Lexus or Toyota. When the battery went dead yesterday was the vehicle jumped backwards at any time?
Customer: replied 4 years ago.

Yesturday I jumped the car with no problems, for the most part im stuck.

Expert:  Skyvisions replied 4 years ago.
After the battery went dead and you jumped the vehicle did it ever start or crank over?
Customer: replied 4 years ago.


The battery has gone dead before in the recent days and each time it has started with a booster with no problems, only until this morning did the same issue occur and this time I couldn't get the car to do anything.

Expert:  Skyvisions replied 4 years ago.
Normally the battery going dead will have no effect on the immobilizer system or set the 2799 code. In some rare cases I have seen where the battery internally will fail even with a jumpstart it can cause issues. If you keep having problems with the battery going dead my recommendation would be to replace the battery to see if that makes any difference. Immobilizer codes such as the 2799 are very difficult to diagnose without the proper equipment. You do not have any other keys to try so there's no way to tell whether it is a malfunction in the system or in the key or just a defective battery. The smart start systems are very voltage sensitive. If the battery needs replaced anyway it is cheaper to do that now just to make sure that's not the issue before you have to have it towed. Have you tried to manually unlock the drivers door with the metal key. There is a remote possibility that the security system has shut the ignition system down. Try locking the doors inside with the door lock switch then close the door wait about 5 min. and unlock the door with the mechanical key open the door put the smart start fob on the start switch and see if it will start even holding the start button down for 5 to 6 seconds.
Customer: replied 4 years ago.

I definitely beleive that the security system may be shutting the car down. The security light has been flashing, I've tried everything so far.

Expert:  Skyvisions replied 4 years ago.
If this is the factory system and nothing has been added to it the flashing light means the immobilizer ECU is not detecting the smart key or at least the immobilizer portion of it. We have exhausted about all attempts to get this revived. You may have simply lost communication with the immobilizer fob.

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