It looks like I'm having my 1st ever Toyota/Lexus electrical issue, aside from just a battery. Dashboard symbol representing a battery came on with my wife driving, and the rig began to slow/run bad shortly thereafter. My rescue mission was to swap a known good battery and drive it home - that worked fine. Does this sound like an alternator? I'm usually a genuine Toyota parts guy, but due to convenience and cost, I may be willing to leave the reservation on this one. Do you think O'Reilly or similar parts store can determine the issue with one of their meters, and provide a part (if it is indeed the alternator) that will be decent?

 

Yes, sounds like alternator and yes O'Reilly's can diagnose properly as can you...

Using a DMM (digital multi-meter) connected to the battery terminals:

- with car off, (a known good battery) battery should show ~ 12.6V.
- with car running, should show ~ 13.5V (range of 13.2-14.4 typically) If less, car is running off battery mostly or alone... If more, voltage regulator is suspect.

Rebuilt alternator, or aftermkt one spec'd properly will be sufficient as alternators are fairly common in design across vehicles as long as load specs are met.

Good luck

 

My first guess would be bad battery, since I already have 258K miles so far on original alternator.
Most auto parts stores will test your battery and alternator function in your vehicle free of charge.
As in the first reply, very easy altermator test is to measure the voltage across battery terminals while engine is running. Any DC volt meter should be fine to use, analog in this case is even better than digital.

 

Sure enough, around 12.6 V at the battery terminals running and off. Trying to find an alternator locally - seems to be problematic. The install looks like a real treat! (detect the sarcasim?)

 

Well... on the bright side, you have what appears to be a good battery.

Not sure how many miles you have but if near 90k, you may consider biting the bullet and doing timing belt & WP at same time... killing two birds w/ one stone as "they" say

Good luck

 

To check if the alternator is dying, Why need to check the battery Volt. I think you should directly target the Alternator .
1. The Following Amperage should be available at these checks.
1. While Inspecting Charge without any load whatsoever, that is Disconnecting the wire of X terminal ( which is at the lower end of the Alternator and connect it to the Negative lead of the Ammeter.
2. Connect the Positive(+) lead of the ammeter to the same terminal X.( located at the side of the alternator clamped with a cord clip. X I have given just for ref sake
3. Now Connect the positive (+) lead of the voltmeter to also the terminal X
4. Ground the Neagive Lead of the Voltmeter and check the charging circuit. That is while Engine running at 2000 RP, you need to check the reading on the Ammeter and Voltmeter.
Standard Amp 10A or less
Standard Volt should be between 13.2 - 14.8V.
If the Voltmeter reading is more than the STandard Volttage, you need to replace the Voltage regulator.
If the Voltmeter is reading less than the Standard Volt then you need to check the following.
You need to inspect the Charging load across you SUV.
1. To do this Ensure you Engine running at 2000RPM, turn the High Beam of yr headlite and place the Heater Blower Switch to HI and now check the Ammeter reading. The Standard reading should be 30A or more. If the reading is less, then you need to replace the Alternator or get repair it.
This is standard Industry wide inspection for Alternators, We do the same on Aircraft Engines.

Now Second it Visual Checks - Carry out the wiring harness if they are fixed properly, check for Abnormal noises. Finally check while you turn the Ignition ON Check that the Charge Warning Light comes on. And when you start the Engine, That lite shud go off.
You could carry out the same.
Hope it helps

 

Mann777 - Of course your logic is very sensible and would be followed to a "T" in an ideal world. Turns out that under the hood of my GX is no such world! How on earth would you get to the alternator terminals? I think those #s could be checked more remotely if one had a good understanding of the wiring harness - I do not. But I would submit that it is physically impossible to check loads at the alternator, unless, perhaps, you had already disassembled enough of the vehicle to prepare for the alternator swap. And then, "watch those fingers!" I really could not access my terminals untilthe alternator was dangling by the wires!

In any event, my rough troubleshooting paid off. Pep Boys alternator for $159 w/ lifetime warranty installed, problem solved. Probably 5 hours for me, but I bet I could do it in half the next time. Today my time was worth it, given $500+ shop estimates and the fact I had no other vehicle to use for a drop-off, etc.


Thanks to everyone who responded.

 

Just a word of advice, In the future I would not take my car to Pep Boys. Everyone I know including myself had bad a experience with them. Their mechanic are not professionally trained.
-My 2 cents.

 

No Pep Boys touched it. Pep Boys alternator. I did the work. 2+ day wait for special order from other sources for 2x the $$. Lifetime warranty. It appears to be a genuine OEM case, rebuilt in Taiwan. Not my 1st choice, but certainly appropriate for the circumstances.

 

I just ran into the same problem this weekend. Fortunately I was able to make it home. Taking off the alternator on this bad boy was tough! I had to get this fixed yesterday - relieved that Autozone was open on Easter so I just threw in a Duralast alternator. I only had 70k on my 2006 on the car so I'm a bit surprised the original already died.

 

I'm surprised too since I have over 261K on original 2003 alternator, factory original battery was replaced 2 years ago with same oem.

 

thats crazy 261k miles? How does it drive still? How many miles did you buy it with??? Thats lexus engineering haha!

 

It runs and drives silky smooth, my wife doesn't want to come out of it and never touched my ML Mercedes since; do to soft and relaxed drive of the GX.
I paid for it whole $2,500 year ago fully loaded with bad engine (broken timing belt and bent valves) at 256K miles on it. Towed it home, replaced heads, water pump and timing for $900 and voila! Radiator had a slow leak, added another $230 for OEM Denso but didn't have to touch it in passed 9 months. Famous clunk was present but regreasing driveshaft permanently fixed it.
First owner was mayor of West Chicago (that's why every option included), secont was saleman (that's why so many highway miles on it) but still very nice and clean top of the line SUV.

 

AAA guy just left. They did a test and the diagnosis is that the alternator is bad. Draining the battery. I thought it was a bad core cause on the way the navi and stereo were turning off.

Very unexpected and very dissapointed as I just did the timing belt not two weeks ago. Driving the RX till I can deal with thre extra cost. I am thinking $160 + $400 or so from my mechanic. Grrrrrrrr

 

I just had this happen night before, had to tow it to Toyota, Lexus is hour away. I believe it to be the alternator. Due to the battery is new.
Last week being a good Mother, I had to break my rules and jump her car off. I dont like using my car for such. So I was thinking maybe a lose connection on my cables now. Or my alternator.. The car drove great all day, however I did notice at a stop it fumbled taking off, I thought my boot heel.. Then later standing on the side of road waiting on a tow.. Soo any inputs and what costs maybe ..How long does it take to replace in the sc430.