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Battery and A/T temp high light on


New Member
Jul 30, 2022
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Hi everyone. Looking for some help / guidance. I have a 2001 100 series 2uz. This morning I went out to start it. Started no problem but the battery light and a/t temp high light stayed on even though the car was cold. Other then this the Cars running fine and not lumpy. Battery is showing good charge wise on the dash and the belts were all replaced less then 2k miles ago so they are all good. So I'm just wondering would anyone in the brain trust here have any idea what the issue might be. Thanks. Peter
Hi Karl. The dash is showing it holding the charge right in the middle. Don't have access at the moment to a metre to check it at the battery but starting each time perfectly
Fist thought was the alternator as you know the battery light usually means it's not charging. Does the battery light ever go out?

You say the fan/aux belt(s) has been changed - obviously it's the exact right belt and it's not slipping etc
Ya that's what I was thinking too with the battery light so that's why I checked the belt but all seems to be in order. Headlights don't dip either. Its the a/t oil temp light I was more concerned about as the car was cold. Its not a daily so has been about 10 days since I last drove it
From the Haynes diagram it looks like theres two temp sensors on the auto box. Can you plug in a scan tool and see what they're reporting in the live data?

Can't see any obvious link between the battery light and the temp light, but lots of weird things happen when the battery / alternator voltage isn't reliable - maybe check battery and alternator terminals for good connection and ensure no resistance between battery terminal and the cable itself and also check low/no resistance between battery negative and any ground points you can find (terminals, alternator case, engine block etc)
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Mechanic is going to have a plug in tomorrow evening and see how we get on. He agrees with you and reckons the alternator is on the way out. The gauge in the car reads half but he thinks it should be 3/4 so not charging the correct amount. I have read that these throw up some odd faults when there is a battery issue like what you are saying. The mechanic is a gent but doesn't really have much experience with these types of vehicles so I will pass on the info and hence me coming here for some advice aswell. They are rare beasts over here so there is pros and cons of owning them. Thanks a million for your help so far Karl and if I can ever do anything for you just ask.
Little update. Turned out the problem was the alternater as first suggested. Also finding one wasn't easy either but it's fixed and back on the road again. Thanks for the help and suggestions.