740ilsamue, that makes 2 of us who can't get the screen to show. Has anyone with a '01, '02 or '03 able to use this on-board voltage diagnostic test screen?

 

The on-board voltage reading shown at the bottom of post # 1 above is not available on '01 - '03. It does come up on my '06. The voltage reading on the screen (just after start-up) fluctuates from 14.1 - 14.3 v. --> 65K miles on the clock.

 

my alternator seems to be whining so i checked voltage through the nav screen and i am reading 12.2v not running and 13- 13.3 running.should i replace the alternator ? anyone know the best place to get a denso.thanks jim

 

What year, Jim? The '01 - '03 is part #210-0508. '04 - '06 is #210-0507.

Amazon is best for Denso remanufactured since no core charge. Here's the '04 - '06 Denso.
Here's my thread: https://www.clublexus.com/forums/ls-...001-ls430.html

Read this thread for '04 '- '06: https://www.clublexus.com/forums/ls-...ernator-3.html

 

tom its a 06 with 102k miles.i ordered one from advanceauto for $224 total core charge is $65 so $159 after its all said and done,denso alternator.i wish i could pick up at store but shipping only.

 

Jim, I would have the alternator properly tested first. Voltage is not really the proper way to test them. Amperage under load is. Voltage can vary a lot based on many factors. I kind of got carried away figuring this out and pretty much needlessly replaced my alternator but it's not a big deal. I don't have to worry about it now. Bad cell(s) or a failing battery will also affect the alternators readings. There are lots of shops in GA that can properly test the units. Amperage and doing a voltage drop test would be best.

Also, If the battery is old might be time to go ahead and replace it. I went with the Everstart Maxx line at Walmart made by Johnson Contols based off Consumer Report reviews. Comes with a good warranty.

Also, if you do need or just want to replace it I would seriously suggests not using the autozone brand and getting an oem Denso. The quality difference is tremendous. Amazon has good deals on them. LexTechs can source them locally too but their prices are not so great.

 

Lavrishevo is right on the money. A toyota or Lexus dealer can do a full diagnosis or just go to a parts store for a fast/free check.

 

I checked mine and it sis 13.7 at Coled star but then I maximum get 13.3 to 13.6. Battery new not eavin a month old.
New alternater will be in the plan next month.
The OEM is 130 amp, is it beter to fit a bigger one say 160 amp. Will it effect any thing.
Mine is OEM not planing to do any upgrades like amplifier. My understanding is the bigger alternater will last longer and reduce the load on the engine.

 

Probably nothing wrong with it. Have an amperage test done. Anything over 13 volts is normal. The voltage is directly related to amperage / draw. Have it tested properly before throwing your money away.

 

Of cours I will do a load test befor I replace it. But got the care about 2 months ago, the battery died after a month. Battery was new about 5 months old, but decided to go with a new one (Duracell) because of 2 things. The car was parked for about a month during that time it did not move mutch and the battery was AC Delco witch is not an amirican make. And the quality of that battery is rubbish at best, it's like ther is a timer in them they go bad after the warranty is over.
Had one died a day after warranty, another a week after, the there'd 1 months after the warranty.

 

lav,my alternator is whining so i check the voltage on the nav screen for kicks and grins.i ordered a denso from advance auto also i can smell the brushes burning a little.
two weeks ago i replaced the tensioner pulley and come to find out it is my alternator.the housing for the tensioner is bolted to the alternator so the vibration(noise)went straight to the tensioner pulley.will update when i get the alternator.

 

That makes sense Jim. If mine were whining and smelling burnt I would replace as well. 12.2 is a bit low on the battery but this could be because of the alternator is not charging it fully. If the battery is old might be worth replacing it at the same time.

 

i put a new battery in 2011 and it is the yellow top and havent had any problems yet.will see after the repair.

 

I use to have a yellow top in my LS400 as well. I always thought they were good batteries but I never saw them included in the Consumer Reports reviews. Not sure why. They are known to be more forgiving for those who play music with the car off, draining the battery down, and being charged rapidly by the alternator.

 

last year i left the map light on for 3 days and it had 10% left in it. i put a charger on it and it didnt miss a beat.i will buy another one when this one bites the dust.