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Pete, Technician
Category: Lexus
Satisfied Customers: 27834
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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2008 ls460 swb with check generator alert. Came on after

Customer Question

2008 ls460 swb with check generator alert.
Came on after replacing battery and starter. Can drive car 30 to 50 miles no problem. Then if i shut it down and come back aftwr 5 to 15m to leave again.. i get the msg.
We replaced the alternator and its still happens.
Submitted: 1 year ago.
Category: Lexus
Expert:  Pete replied 1 year ago.

Hi my name is ***** ***** I will be happy to help with this today.

With the battery and alternator both replaced with the message you see here the computer is seeing an issue with a charge output from the alternator and it looks like at start up.In some cases you can receive a faulty alternator with it needing replaced or rebuilt to correct this.I have run into this before a few times.I would have it tested and the battery as well just to make sure what you received is good parts.A local parts store will test these in your vehicle free of charge and let you know.

The other common fault is the battery current sensor itself.It should be located near the battery as shown below.This is a common component that fails internally and tells the computer that the alternator isn't charging properly and turns on this message.I have had to replace several of these before for this issue.

Check and make sure the cables from the battery to the alternator are clean and tight as well as at the large 150 amp fuse leading from the battery positive to the fuse panel.If these are all o.k. and your battery and alternator test good the battery current sensor needs replaced.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

Customer: replied 1 year ago.
ill check the voltage/outputs. We replaced the alternator after seeing this issue.. the old alternator tested fine.. certainly not at new rating after 90k miles. Its likely the battery current sensor and or a need to clean battery terminals.. fuse.
If my response adjusts your recommendation.. let me know
Expert:  Pete replied 1 year ago.

This is correct.Most likely you will either find an issue with the battery connections at the battery itself,alternator or to where they run and connect to and these will need cleaned or replaced or if these are all o.k. I suspect the battery current sensor needs replaced which is a common component to fail and causes this message here.I am leaning more on the sensor needing replaced as it is most common.It is easy to replace,you disconnect the battery and the cables from it and remove the bolts and replace it.

Thanks Pete

Customer: replied 1 year ago.
Is the battery current sensor something an autozone or oreillys would have.. or musti goto lexus? Also.. this there a spefici part number and name for it
Expert:  Pete replied 1 year ago.

I apologize for the delay.

My info doesn't give me the part number for it and in most cases this would be a part you would have to purchase at a dealer.It is called a Battery Current Sensor.You can call/check with local parts stores but I have had to get this from a dealer myself.

Thanks Pete