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Battery charge light will not go out following alternator and battery replacement

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OK, what should have been a simple alternator change has turned into a fiasco with the local Toyota service department.

Three weeks ago the alternator starts to fail on a trip to Sydney from the Gold Coast, car dies at Hexham 160 kms from my destination. The NRMA guy tells me the alternator is not putting out enough volts to charge until it is revved at which point it is charging but he reckons it will be dead shortly.

Long story short, I have a LOT of important things to do so I push on to Sydney and the car gets there fine with the battery charge light out all the way.

While driving around Sydney of a night time I find all I have to do is knock the gearbox into neutral and keep the revs up to keep the alternator charging the battery and the light stays out.

The car gets me all the way home and then I send it to the local Toyota service people to have the alternator swapped out, this is done but now the battery light is on all the time.

New battery is fitted, still the light is on, another alternator is fitted, putting out 13.8V at idle but still the battery charge light is on.

They reset the ECU codes to put the light out but no good.

Now they are saying that possibly there was a surge or spike that went through the system and fried a wire ............. if this happened then it was them that did it.

Has anyone ever seen this before as I know it was fine when I put it on the back of a truck to be sent to the service people because I had to put another battery in and the car started fine and all the lights were out.

Are the Lexus people the only one that can fix this ??

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What model?? check the charge rate yourself with a volt meter at the battery 13.8-14.2 give it a rev, it maybe a computer issue let us know how you go.

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It's an IS250 sport luxury if that makes any difference, I checked it with a new multimeter and it is a steady 13.94V and moves minimally to 13.97V when revved to 2000 .

The battery is reading 12.97 with the car turned off as this is a new battery put in 2 days ago.

They suspected the new alternator was not putting out the right voltage so they got a new one and it went from 13.5V for the old to 13.9V for the new but even after clearing the code the battery light remained on.

If it's the computer can this be fixed without a new computer ?

God only knows what Lexus will charge for that :wacko:

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OK, got some sanity today from another service centre which all makes perfect sense in hindsight.

The service people I went to couldn't get the right alternator so they put an after market unit in that charged but wasn't recognised by the computer so when you rev the engine it didn't change the charge rage and also the computer kept the battery charge light on due to computer to alternator lack of communication.

The Lexus unit is the same as a lot of other Toyota alternators but the units the first service people tried were not compatible with the Lexus ECU so battery warning light.

I'll update this when they put the new alternator in next week :whistling1:

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