Warning lights electrical problems

Geggy · February 8, 2016

Hi I need help. I have a rx400h 2006 150,000 miles, it's been faultless until the other day I came to start car and it started fine and then hybrid check light and Vsc light came on, I continued to drive and got home fine, the next day I decided to replace 12v Battery, but it is still the same, I also have various other electrical problems that are related to this.....tailgate won't open, mirrors won't work, electric Windows only work off individual button, no cruise, afs lights don't work, central locking works off fob( delayed) but not off button inside car, also you can hear the central locking make a noise once the door is closed. The car still drives fine, charges as it should. I've checked all fuses, I've plugged it into diagnostic and it only shows 1 code, u0146....lost communication with gateway a. My sister has identical car so I changed the gateway ecu over but made no difference, I'm wondering if anyone may have any ideas on this before I bite the bullet and take it to the dealers? Thanks in advance

Bluesman · February 8, 2016

Hi Greg and welcome to the LOC, we are a friendly bunch and some of us even know how to pull them to bits and put them back together again, with of course the one bolt and washer left over.

I cant help with your present queries but I'm sure someone will be along ASAP.

We recommend you spend a couple of mins looking over the rules of the LOC, we will be asking questions later

http://www.lexusownersclub.co.uk/terms-conditions/

Regards Mike.

RXJasonRX · February 9, 2016

Hi. Cars this complex need to be taken to the dealers I think. Long gone are the days when you can do them on the drive

Sent from my Nexus 7 using Tapatalk

Colin Jelf · January 15, 2020

Hi

Did you get your fault fixed as I have the same faults exactly

thankyou Colin

Herbie · January 15, 2020

I think the Gateway ECU may be faulty but I don't think you can just swap it out with a known good one to confirm that without it being coded to the car first.

crosscyl · March 11, 2020

On ‎2‎/‎8‎/‎2016 at 4:27 PM, Geggy said:

Hi I need help. I have a rx400h 2006 150,000 miles, it's been faultless until the other day I came to start car and it started fine and then hybrid check light and Vsc light came on, I continued to drive and got home fine, the next day I decided to replace 12v battery, but it is still the same, I also have various other electrical problems that are related to this.....tailgate won't open, mirrors won't work, electric Windows only work off individual button, no cruise, afs lights don't work, central locking works off fob( delayed) but not off button inside car, also you can hear the central locking make a noise once the door is closed. The car still drives fine, charges as it should. I've checked all fuses, I've plugged it into diagnostic and it only shows 1 code, u0146....lost communication with gateway a. My sister has identical car so I changed the gateway ecu over but made no difference, I'm wondering if anyone may have any ideas on this before I bite the bullet and take it to the dealers? Thanks in advance

On ‎1‎/‎15‎/‎2020 at 3:48 PM, Colin Jelf said:

Hi

Did you get your fault fixed as I have the same faults exactly

thankyou Colin

Hello all. Hard to believe it but I have exactly identical also as described by OP Geggy. OP did you get it nailed in the end ?? Would be most helpful if you can please chime back in just to give an update. Mine self corrects itself after a couple of days. All warnings disappear. Car always drives normally. This makes me think its a module / ecu / rusty contact. I am on my second episode of it roughly three weeks apart. On the first one, in addition to the very good description by the OP above, I also had the Centigrade/Celsius change to Fahrenheit on the screen for the duration of it which lasted a couple of days. All self resolved. Car has had a new 12v Battery since and has been checked for water ingress - thankfully all dry under the boot. Second episode yesterday, all self resolved today. I am awaiting a code reader to arrive. Last time there weren't any although by the time it was read, the errors had self cleared by then. No idea when the next episode is due / expected. I have seen the Hybrid Vehicle Control ECU mentioned in relation to these exact symptoms. Any clues / suggestions would be most helpful, thanks.

crosscyl · August 28, 2020

Currently going through another episode of this 🤨. Been to a specialist previously about it - no joy. No water ingress. No one seems to know what this one’s about. Rare one but certainly not totally unheard of as the above threads all describe the same very specific features. One to ignore I suppose as car is flawless otherwise. Just really annoying as boot can’t be opened during ‘the episode’ (can last one day or more) until it eventually self resolves itself, no memory seats during it, only driver’s window works from driver’s panel. Other windows only work from individual doors. My hunch says its a faulty control module somewhere which plays up only randomly without any links or asscoiations or triggers. The codes don’t persist. Indy said there was something which suggested some voltage variations but he couldn’t nail the root cause. Exhausted the forums. Doubt even a main dealer will nail this one. How frustrating. Anyone up for a challenge to try figure / diagnose this one (in person or remotely) - feel free to get in touch - I’ll more than happily drive some distance to have this never occur again !! I’d hate to sell it onwards to an unsuspecting buyer like this. Almost certain why the private seller I got it from shifted it. Can be episode free for months ...so would be very easy to shift onwards. Any clues or suggestions gratefully appreciated, many thanks !!

Herbie · August 28, 2020

Sorry to say I have no answers for you but I'm just curious about:

Quote

Been to a specialist previously about it [...] Indy said there was something which suggested some voltage variations but he couldn’t nail the root cause

Was that a properly qualified auto electrician?

I'm a firm believer in mechanics for mechanical and auto electricians for auto electrical work, especially for something as complicated as this.

crosscyl · August 30, 2020

On 8/28/2020 at 11:52 PM, Herbie said:

Sorry to say I have no answers for you but I'm just curious about:

Was that a properly qualified auto electrician?

I'm a firm believer in mechanics for mechanical and auto electricians for auto electrical work, especially for something as complicated as this.

Nope it wasn't an auto electrician - it was a Lexus independent specialist. But I agree now that this certainly needs an auto electrician specialist and that's what I'll do. Now hoping that it doesn't self correct itself until I get there or I'll need to wait for the next round / next episode before I travel to the electrician.

crosscyl · September 7, 2020

So this time it didn’t self correct like on previous occasions - which in a way is good as its now having diagnostics at an auto electrician.

m4rkw · September 10, 2020

Did they manage to figure out what was wrong with it?

Deynnis · July 28, 2021

Hi. I have the same malfunction. Does not work: central locking, mirrors, high beam. The temperature is shown in Fahrenheit. Previously, they said it might be a matter of additional (Alligator) signaling. Car rides. But the rear electric motors are not connected. Rear and front motors work for braking. Did you fix U0146 breakage?

Deynnis · August 10, 2021

Hi.
My car was repaired.
The contacts were in good condition. The electrician suggested that the BODY ECU is defective. We could not check it. We put a similar one from the right-hand car (I have a left-hand RX400). Repair cost + BODY ECU around £ 100.

Jollyjacktarjack · November 4, 2021

Hi all,

I have a carbon copy of the symptoms that crosscyl and Deynnis relate to above, does anyone have a definitive solution please?

Thanks

JJTJ

crosscyl · November 4, 2021

It’s due to possible moisture in the wiring / modules located behind the glove box (the issue with my car) and /or an issue with ‘body ecu’ (the issue with Deynnis’ car).

Really annoying problem - at one point I thought I need to get rid of the car due this. Like Deynnis, thankfully mine too is fine now.

Unless you know what you are doing and handy with doing this yourself - you need an AUTO ELECTRICIAN to diagnose and sort this for you. Good luck.

Jollyjacktarjack · November 8, 2021

Morning Crosscyl,

Thanks - so after a few dry days my Lexus has settled down and all lights (less the Lambda O2 sensor) have extinguished and normal service has resumed. I did take it to a local dealership and they produced an eye watering quote for them to do some investigatory work.

So, I spent a couple of hours resealing the known problematic areas around the rear tailgate and rear roof bar bolts. Interested in more details on the glovebox situation, assume that is water ingress around the windshield that causes that?

Thanks, JJTJ

crosscyl · November 8, 2021

This is the frustrating part with this issue - it goes away and then randomly returns. All very intermittent and unpredictable. May not even be any sort of water ingress whatsoever. Could even be simply condensation related to changes in ambient moisture and changes in weather !! Episodes started getting more frequent and of longer duration when I had had enough of it but thankfully it was somehow sorted by the electrician. In my case I don’t know what exactly the issue was - I was just told they looked at and identified some condensation / moisture in the wiring behind the glove box. This is different to the situation with Deynnis where changing a specific module / item was identified as the fix to this. Certainly not quite a DIY for most people. I searched high and low for threads all over the internet on forums - bumping up old threads (without luck) - where most original posters had never updated or replied to their stories as to what exactly happened with their cars eventually. In the end car was just left with an auto electrician for a week and hoped for the best. It’s been over 18 months now and the issue has not returned in my car. The most difficult aspect of this issue was that I wasn’t able to open the boot from anywhere during an episode.

Jollyjacktarjack · November 8, 2021

Morning Crosscyl,

Thanks and frustrating for sure!

Thanks, JJTJ

Delphius1 · November 9, 2021

Problems like this really need techstream to diagnose the issue. That way you can get the fault code out of the various modules and have a chance of finding out what's going on.

Something as simple as the brushes on the Battery cooling fans wearing can cause enough intereference on the power supply lines that it interrupts the CANBUS communications between the Battery management or hybrid module and others around the car, causing a cascade of faults. That's because various modules can rely on information from a single module being on the CANBUS network. If it's not there, then all the modules that rely on that information throw errors.

The same goes for a corroded earth causing a faulty power supply to a module, or a single sensor failing. The cars are so complex that they really need that extra level of diagnostic effort and experience to solve problems.

Jollyjacktarjack · November 9, 2021

1 hour ago, Delphius1 said:

Problems like this really need techstream to diagnose the issue. That way you can get the fault code out of the various modules and have a chance of finding out what's going on.

Something as simple as the brushes on the battery cooling fans wearing can cause enough intereference on the power supply lines that it interrupts the CANBUS communications between the Battery management or hybrid module and others around the car, causing a cascade of faults. That's because various modules can rely on information from a single module being on the CANBUS network. If it's not there, then all the modules that rely on that information throw errors.

The same goes for a corroded earth causing a faulty power supply to a module, or a single sensor failing. The cars are so complex that they really need that extra level of diagnostic effort and experience to solve problems.

Hi Delphius1 - thanks for the reply. I assume that Techstream gives a more in depth set of diagnostics than my Veepak OBD reader then please?

Herbie · November 9, 2021

5 minutes ago, Jollyjacktarjack said:

Hi Delphius1 - thanks for the reply. I assume that Techstream gives a more in depth set of diagnostics than my Veepak OBD reader then please?

It does indeed. It's the very same diagnostic software that Toyota/Lexus technicians use in dealer workshops.

If you have a laptop running Windows (even Win XP will do) then you can buy a miniVCI cable such as this one from eBay. It comes with a pirated copy of Techstream but we can't condone the use of that, that's a matter for your own conscience.

The correct way would be to freely and legitimately download a 'real' copy from https://www.lexus-tech.eu/DiagnosticTools/Setup and pay for a block of time to use it (€5/day, €10/week and so on). Whether you go legit or not, you'll still need that cable to connect the laptop to the car.

Jollyjacktarjack · November 9, 2021

Thanks Herbie

Delphius1 · November 9, 2021

This is a video that shows how something as simple as a worn out Battery cooling fan can throw up hybrid and VSC errors. Skip the Diesel DPF diversion half way through. Although it also shows having a resource that points you in the right direction is pretty useful too.

Jollyjacktarjack · November 10, 2021

Great link Delphius1, thank you, certainly food for thought!

Now off to Google an auto electrician in the SW...

Jollyjacktarjack · January 7, 2022

Evening All,

After 3 days the fault disappeared - good news!

Bad news the fault has returned, back seats removed but can't really see any signs of water ingress to the hybrid Battery area. Common sense tells me not to remove anymore covers around the Battery area, will leave it to air and hopefully dry out. Will report any progress back...