LX 470 Alternator/Battery Issue (Low Voltage) (1 Viewer)

[hortandr]

Hello all.

I am looking for some assistance. Problem is as follows. I was heading up north over the weekend when I noticed m car had a Battery light illuminating on the dash. It was not staying on though, it was fleshing rapidly. I will attempt to upload a video today.
That is when I looked at my Voltage Gauge and could see I was only at 12V. While cruising around 75-77mph.
I watched carefully and the voltage stayed low. I ended up missing an exit and had to hit a U-turn. Flooring it out of the U-turn my voltage spiked back to 14V on my gauge and I had no more issues. I thought I was in the clear maybe there was a wiring issue leading to the instrument panel but the next day I started driving and the same thing happened. This time I was not able to increase my voltage. When sitting off my battery is only holding 12.25V per my multimeter.

Any ideas?
I am thinking alternator.
When I start up my voltage drops to 11.68V.

 

[wthomp10]

Battery light is typically alternator. You can get it tested at the local auto store place I believe

 

[Octous]

It maybe the charge regulator (which is a part of the alternator). It’s also possible it is the alt-s fuse in the positive battery lead fuse block.

I had a similar issue it ended up needing a new alternator but I learned about the alt-s fuse along the way.

Basically the alternator has a feedback loop where it checks battery voltage and if it is below a certain level it charges. Above hat level and no charge.

12.4 is below the charge level

 

[2001LC]

The fact that "movement" changed the charge voltage on the dash gauge. Indicates a short! Most common is a loose battery post clamp or one or more wires hanging off it. We also need to check wire on alternator. To often after a service, where alternator was touched (T-belt, tensioner, alternator, etc.), a mistake is made.

Also we need a proper functioning fan belt, it's pulleys and tensioner.

Best to post your model, year, miles and toys wired in.

BTW: Picture of engine bay, battery etc are helpful.

 

[hortandr]

Thank you for your inputs guys. A little update. Day 1 of issue is as described above. Day 2 I have the issue come back and I noticed some things. When I was driving I noticed as I accelerate the battery light flashes and my voltage was no longer increasing, I noticed that at stops the light would come on solid but I was not dropping below 12v and if my foot was off of the accelerator there was no light at all. Reading wthomp10s comment I decided that was a great idea, I might as well stress test the battery at a auto store and then typically they will check alternator if the battery tests good. While on my way there I noticed my voltage was dropping, badly. I lost all lights and electronics inside but was able to turn around and get to the house. I then jumped the car to at least give the battery some juice because I couldn't even put the windows up. I ordered a new alternator fearing the worst but this was before I saw comments from Octous and 2001LC.

2006 Lexus LX 470 112k miles
I hope to GOD none of this is related but I did just purchase this vehicle two months ago and have had a few random issues. Chronological order as follows.
P2440 switching valve 1 stuck open
-cleared and has not come back (Hewitt Bypass on a shelf waiting for code to throw again)
P0031 & P0051 both at same time
-shop checked wiring on HTR o2 sensors and determined resistance etc. is to factory specs and recommend changing sensors to fix. (not done yet)
Driver door does not respond to key fob, most likely locking motor is bad.
- Not fixed yet


Only toy added right not is BT45 TOY I added second day I had vehicle.
I will check the Alt-s fuse and also upload some images today when I get back home.

 

[vipergrhd]

Just adding to what others have stated, if the alternator is the original one very likely it's just worn out brushes you can buy a kit from Toyota if you are brave enough to tackle it you can also check the rectifier while you are there. An inexpensive DVOM will work fine, my 93 Pick up alternator died at 200k and all it needed was new brush and it's back to life after that. Have the battery load tested too a shorted battery could kill an alternator and toast the rectifier which is expensive if you have to buy one.

 

[hortandr]

Thanks for the input vipergrhd. Any Part number you mays till have for that rebuild brush kit?
Also, I have never removed a battery from a car for long periods of time, say a couple days to test everything. Does anyone have any concerns with ECUs or PCMs when removing a battery on a LC??

Just found out about memory savers. I could just use one of those.

 

[2001LC]

Remember with the Hewitt bypass kit install, you're not street legal. IMHO there's a much better solution:

S.A.I. Filter Modification, in VVT engines. To prevent its failure! Alert Alert!

We've a $2.00 part in the S.A.I. (secondary air injection) system of the VVT engine, that is taking-out ~$7,000.00 $15,000 $25,000 (inflation) in parts. WOW! I've a very easy and cheap WORK AROUND. You are going to love this ;) This thread is dedicated to the 4.7L 2UZ-fe VVT engine, in the...

forum.ih8mud.com

These alternator tend to go bad around 250K plus miles. Earlier, if they're subjected to contaminants. 7 out of 10, I replace with lower miles. Have the #1 undershield missing.

But again. The fact your voltage reading changed with movement. Indicates a short (loose connection)

Two things I do when removing battery cables.
1) Clean battery with baking soda and water. Bake soda neutralizes acid.
2) Always remove negative clamp first and install it last

I clean battery post and clamp with wire brush or sandpaper, until shiny. Then coat with white lithium grease. Sung clamps, until clamp they will not spin on post. Do not overtighten clamps or they'll stretch and be damaged.

I also disconnect battery negative post, when cleaning battery, working any electronics even MAF sensor or pulling glove box to replace cabin HVAC filters..

When you reconnect battery in 03-07 LX470. You'll see the VGRS light is on. Just drive in straight line, up to ~25 MPH. Light goes off, then make left and right turns ( i do figure 8's).

The box hanging off the positive clamps, can get acid build up and damage.

 

[KeepGoing]

To me, this sounds like an alternator going out. Speaking from personal experience just a few weeks back, a few lights came on in the dash so I knew something was awry. When I stopped at a light, volt meter pegged then at cruising speed it was back down. Read a few things and suspected alternator. Drove it to my local LC shop and on the way same behavior, pegged volt meter then back down at speed. Also battery light on and off but ultimately stayed on toward the end of the drive.

Shop confirmed it was the alternator and also noticed my battery was shooting acid because of the 19+ volts it was reading. Replaced both and truck has been fine for ~1k miles.

Expensive by my standards. Battery and alternator here ~$900.

The good part I was in town and not out of repair range.

Time will tell if the spike could’ve hurt something else.

Hope this helps.

 

[hortandr]

Ok, 2001LC. What is that attached to the positive terminal? I wasn't familiar with the part. I have some sort of a rodent alarm on mine that can be switched on an off, making a intermittent high pitch screech when on. I am going to attempt to use my thermal imaging camera to hopefully locate any Parasitic draws or shorts. KeepGoing thanks for your input, glad you got back on road. Updates and images to come.

 

[2001LC]

First, it was the U-turn statement that pointed to short. But in the end, you may need and alternator. We need to make sure all in order first, before we test the alt.

"What is that attached to the positive terminal" It should be hanging on your positive battery clamp. Pictures?
It's a type of fuse box. It's use to connect wires to battery. Acid can get in and inhibit connections.

I remove all aftermarket wiring first thing, when I buy one. Last 2003, took three days and I filled 3 boxes with aftermarket wiring and toys. Was it any wonder, it came with battery tender.

If you a DVD player in rear cargo area. It is, a known parasitic draw. There are two inline fuse under glove box. It the hot key off one, IIRC I pull out the red. Some of the headrest DVD, also have a draw. Drop down or headrest DVD screens/players are all aftermarket (not installed at factory). Some of these guys butch our wiring, installing these and other toys.

The alarms I've seen, are for Deer. Switched off shouldn't be draw. But depends on how a where wired in. Easy test: Switch on key off, the key on!

 

[hortandr]

I do have the DVD player system in the back. I will look into these fuses. I also have some sort of a secondary security system in place. I only have one key/fob from Toyota the second is from some other company. Here are some basic images. I do believe the alarm I have under the hood tied to the battery is for rodents but either way here is an image. Nothing appeared to be draining on my thermo camera, my battery was the same voltage over a 24hr period as long as it is the same today I am going to rule out a power drain.

 

[reconranger]

I would second what 2001LC said. The fact that turning changed the voltage input leads me to believe either a loose wire, bad ground, frayed wire or bad alternator. I had similar issues that cause low voltage on my battery which came from a fading alternator.

 

[2001LC]

That does look like a face, on a rodent on the device attached to battery. Switched off, shouldn't be a draw.

Battery clamps "look" okay.

Make sure wires on alternator on correct. I've seen where the main hot wire which (has a gray cap covering it) has two prongs, not seated properly, or nut its not torque down, or wire stabilizer not clip into bracket on side of alternator. Or the wire housing block (plug in wires) not secure, due to busted retainer clip or wire housing not pressed all the way in locking it in.

In the end, it may not have been the U-turn movement. But the acceleration increasing RPMs increasing volts. If that the case, you'd likely see dash battery meter low (<~12V) at low RPM and higher (~14V) at higher RPMs.

The rear RH cargo DVD wires run under glove box, in the ones I've seen. I've seen where they'll be a draw at times and not at others.

Toyota's that come on Southern USA depot, go to a central location for these add-on's like DVD. So most installs are the same. In Northern states, the add-on's are done at Dealerships. So the vary how installed.

Parasitic Battery Drain drop down DVD

This can't be normal? The DVD player face plate light is on and I hear CD internals/motors with key on or off and drop down screen closed.

forum.ih8mud.com

Also:
You'll see in OM, it states: Do not leave headlights in auto position during prolonged parking. The reason is the light sensor (solar eye on dash (button)), draws amps when we do.

A battery not keep full charge, will sulfate and no longer except a full charge.

I notice you brake fluid reservoir overfilled and dark:

Brakes ...... Overdue write-up.

First and foremost: Brakes should only be worked by those, with high level of mechanical abilities and experienced with brake systems. With the age of all 100 series today, in our aging fleet. Any issue, with brake master assembly. IMHO, best and safest course of action. Have the whole brake...

forum.ih8mud.com

If you click on my master link below in signature line, you'll find many helpful links.

 

[hortandr]

Hello Gentlemen. I have been absent for a few days.
Here are my updates. I removed Battery and Alternator Friday night after work. Took them both to get tested at a local parts store. Alternator tested bad. Battery tested low, makes sense it tested low. in what I can only assume is proper land cruise fashion I immediately drove two hours north into the mountains with no issues since. I am working on a bit of a write up for the alternator job for those in the future. I will post here eventually. I do have leaky brake lines that I just noticed. There is some sort of a coupling fitting on both sides of brake lines leaking and weeping down frame etc. I will be most likely doing what 2001LC recommends and replace all brake lines etc. The vehicle is almost 20 ears old and many old parts are failing due to material etc.
Thank you all for your assistance, especially you Mr. 2001LC you are very well versed and inspirational in your LC knowledge.

 

[2001LC]

"coupling fitting on both sides of brake lines leaking and weeping down frame etc"

Again pictures are very helpful?
On the PS side front brake line. We see power steering leaks often, from reservoir hoses. These leaks, very often are mistaken for a brake line leak. As the drip onto brake lines.

Flexible brake line union (flare nut), between hard line and flexible line. I never see these leak, if still the factory install. But may see leak, if every touched after the factory install. The flexible lines do get old, and weep or even burst. Hard lines due rust out and leak, in rusty vehicles.

We lose brakes for one reason. No pressure!
We lose pressure for two reasons: No fluid or booster motor fails to run.