stubble

Hi all, on my 2011 GX460 I have been having a strange electrical issue: initially the NAV occasionally rebooting while I’m driving. Then I noticed that all the lights flash off for a split second when this happens. Last night it was bad, happening a lot, and I saw the LED running lights actually flickering slightly while parked with the engine running as though there was a low voltage situation.

Battery connections are good, battery is pretty new. Do I check the alternator? Regulator?

thanks in advance.

Acrad

What voltage is showing up on the battery posts while vehicle is running? If it is less than like 14.2 or 14.3 I believe that could make alternator suspect

stubble

I have a radar detector that shows voltage and usually it’s over 14 but I did see it was low 13s and even below while this was happening a lot last night. I didn’t check at the battery. Today it’s back to normal (this behavior is intermittent) but I’m going to check at terminals anyway. Would it be unheard of for an an alternator to fail intermittently like this?

how is the r&r job on the 460?

NewB2Lexus

I strongly suggest you to get to the bottom of this. If your alternator is not charging properly and your battery starts running out your least problem will be the NAV reboot. The engine and drive train are all controlled by electronics that need proper power.

I would check the connections at the battery and the alternator first. A loose cable can cause all sorts of problems.

stubble

Hi all, I have not made any progress on troubleshooting this issue. It seemed to have gone away for a while and I got busy. It's been happening this week and I have a couple of new observations:

• When the issue is likely to happen, the voltage reading is jumpy, fluctuating from 13-14+ rapidly (read on my radar detector display). If that is happening, I can predict that the next time I hit the brakes or some other sudden electrical change occurs, the nav may reboot and lights will blink out for a second.
• If the voltage reading is steady, none of this will happen.
• There's no pattern to when it's steady or erratic, just comes and goes.
• I've had no flat battery issues

All that feels like a voltage regulator. Right?

Anyone have a DIY replacement steps or video for the alternator? I can only find first-gen info.

Thanks

John00

your radar display is not good enough for reading a voltage. it will have some averaging that cancels out short quick spikes and dips. You need to get an oscilloscope or some higher frequency voltage logger. you might be going from 9 to 25 and not know it.
to stabilize voltages you can add capacitance. this doesnt address whatever the root cause is but it does smooth out fluctuations. The battery should be enough to stabilize voltages but if the drop is more localized you might need closer placed caps.

clearmysix

This happened to me. It was simply that the battery terminals were not tight enough. I know it sounds strange because you will look at the terminal and it looks okay, but try to loosen the terminal, move them around a bit, then re-secure the bolts.

stubble

Just to follow-up, it was indeed the alternator (regulator). Dealer is replacing the alternator. It's an EXPENSIVE part at the dealer, plus several hours labor.

NewB2Lexus

Wow, it's in the $750 range online which is quite steep even for a luxury brand. Looks like Rockauto has Denso re-manufactured, which I would trust in a heartbeat, for the fraction of this price.

John00

remy has remans for about 140$

GX460SA

Hi all, 1st post on the forum. This symptom seems to have popped up on wife's 2014. We just got it a month ago with 75k. Car died on her yesterday morning and she brought up the fact that the radio would cut out from time to time. Didn't say a word till yesterday. I did find the positive terminal loose on the battery. Very surprised since we had bought the truck from a Toyota dealer and would have expected them to have checked it out in the detailing process.

So right now it's showing 13V with the vehicle running. Seems a little low. I fired up my 5.7 Tundra and see the voltage at about 13.5 so not sure if they run lower as I would imagine the electrical systems are very similar between the 2 as they are both Tundra type engines. She has an appointment tomorrow at the Lexus dealer, but I worry about them charging an arm and a leg should they say that the alternator is bad as I'm pretty handy with a wrenching on vehicles. I may just have her take it in and have the system tested and look for codes. What say the hive? I am assuming the regulator is in the alternator as I don't see the part available at Rock Auto. TIA

PhillipT

Regulator attaches to the back of the altenator. In theory it could be replaced separately, in practice it is usually done as an assembly. Buy reman Denso, swap it yourself...

GX460SA

Yeah Phil, I'm thinking 13 Volts is marginal at this point. I'm going to let her take it in and get them to test the electrical system and check diagnostics. If they say it needs a new alternator, I'll tell her to bring it home. If the price was reasonable say $400 or so, that's one thing. If they say more than that, that's another thing. I've just not had any issues with alternators on my Infiniti I had or her 2006 RX. This is a new car for us. We buy older cars these days. But we go for quality and dependability and not having a car note. Plus all the gadgets these days aren't that appealing.

PhillipT

13 is a bit low, normally it hovers around 14 with the turning engine. The replacement should not require special tools. May look at changing the belt as well since it is coming off anyways. I always check the idler pulleys when i do belts just for the peace of mind.
I am with you on the staying off the payments routine. To me 3 used cars in the family (his, hers and a spare) is the way to go. You can take a break and order parts online at a quater of dealers price.

GX460SA

Copy that. I'm going to let her take up to the dealership and see what they say. I told her to tell them she wants the rundown with diags etc on the truck and estimated costs for anything wrong that needs attention. It needs a high amp battery like a truck battery. At least they will wash it and try to get the business for $125. I want to see the report. It's worth a 2nd opinion. But they won't do a transmission fluid swap. Hmm