A weird thing happened on the way home today...

[CPN]

Apologies up front for the long post but you'll see why... (my first real fault on my Mk4 maybe?)

On the way home, we stopped to fill up and something strange happened. I switched off and got out (wife still seated) and tried to open the tailgate to get my e10 additive out but the button wouldn't open it at all. So, I locked and unlocked the car again with the fob and this time, the tailgate opened. I thought nothing more about it and got on with filling the car.

Once filled up and paid for, when I got back into the car and started up, I straight away noticed that the HUD display was low (gone to its default position) from where I normally have it. It was as if the car had done some sort of "reset/refresh" or similar because when the radio started up it was "audio off" and when I switched in on, it defaulted to FM (which I never use) and at the bottom end of the band. After adjusting the HUD back to the position that I like and setting the radio back to DAB+ etc, we started to set off once more. Before I got going, I noticed that my window wouldn't "auto open/close" using the second pressure. I had to manually hold the button up or down for it to work (fully open or close). So, I quickly checked all the other windows from the driver's door controls and the windows on the nearside of the car worked as normally with the auto function fine. However, on my side of the car, I found that I couldn't operate the rear passenger window at all with the driver's control. Dead as a doornail. So reached over and used the switch on the door itself and although I could manually power it up and down from its own switch, the auto function wasn't working from that either! Curiouser and curiouser...

We set off and once home and parked in the garage, I decided to do some more digging with the Carista app and my OBDLink LX dongle. Whilst getting stuff sorted, I pressed the start button to get to ready mode and although it initially came on, a couple of seconds later everything went black and there was no power at all! Panic!!! Got out, tried the door locks, nothing, everything was dead. It was as if a contactor had flipped and cut the whole car off! Whilst I was trying to understand what was going on, suddenly the car powered up again itself and everything came back on into accessory mode but not "READY" (foot not on brake as it came back) without me actually touching anything! Straight away I noticed the HUD was down again, tried the radio and "audio off" again like last time and then into FM etc etc.

So, I depressed the brake pedal and went straight to "READY" mode to scan for fault codes. Nothing, no fault codes showed up. Checked my door window, auto function had returned and working normally. Rear passenger window on my side, still acting up. So, at this point I used Carista's deep dive diagnostics to scan all the ECUs and guess what popped up?

...and trying to reset it, did no good as you can see...

Anyone else experienced this or similar? Any ideas?

Before anyone suggests it, my 12v Battery is in rude health hovering between 12.8V & 13.0V when the vehicle is off.

Looks like a visit to the dealer is coming up...

 

[anchorman]

I don’t know Colin.  Yesterday I fitted a new Battery to my mate’s Yaris as he had been getting increasingly more frequent fail to starts.  We went for the upgraded output Yuasa Battery but my point is, it wouldn’t unlock the boot until I’d locked it and unlocked it again.  This is normal initialisation process after disconnecting a Battery.  I just wonder if your battery terminals are tight?

[TonyHSD]

Yeah, Battery terminals or perhaps the ground of the car there could be few to check and eventually a switch or fuse that can totally disconnect the 12v supply, but I am not good with electronics to tip you more. The rear window couldn’t complete the initiation process as a result of losing power imo. Strange indeed. Good luck and let us know . 👍

[Cyker]

I reckon it's the battery; Those are classic battery-starting-to-fail symptoms.

You need to see how the Battery is under load - When they start to go, they show okay voltages under no-load, but then sag below the minimum threshold when a load is applied to them.

There are some things like the brake booster vacuum pump which draw a load of current when the car 'wakes up', which could cause voltage sag. Once the brake booster is charged, subsequent attempts to power on the car are more likely to succeed as it doesn't have that big current draw spike, and my initial gut reaction is that's what happening here.

This does lend more credence to the bad batch of batteries theory of why there are an unusually high number of Mk4 owners with Battery issues, as they definitely should last more than 3 years!!

 

[flash22]

There is a known issue with the 12v Battery terminal, it's worth a check to make sure it's all tight, the Battery is lot cheaper than the agm one in the Mk3, iirc the Battery is only covered for the first year after that it's a wear and tear item

go get the battery tested, i bet it's dropped most of its CCA rating

 

 

[MikeSh]

4 hours ago, Cyker said:

the brake booster vacuum pump which draw a load of current when the car 'wakes up

It's annoying that it does this on opening the driver's door (on my MK3 anyway), though I can understand why.

If the car has stood for a while I usually try to get my foot on the pedal and press start as quickly as I can after opening the door, so the main Battery can do more of the heavy lifting at that point. Only delaying the inevitable of course.

Bright/dim idea ... When Battery is iffy leave the drivers window open when parked (security, weather, cover allowing). When it's time to start unlock the car but don't open the door. Reach in with a stick to press the brake and press start. Then get in. Would that work? Or does the driver door need opening before the car will start?

[TonyHSD]

1 hour ago, MikeSh said:

It's annoying that it does this on opening the driver's door (on my MK3 anyway), though I can understand why.

If the car has stood for a while I usually try to get my foot on the pedal and press start as quickly as I can after opening the door, so the main battery can do more of the heavy lifting at that point. Only delaying the inevitable of course.

Bright/dim idea ... When battery is iffy leave the drivers window open when parked (security, weather, cover allowing). When it's time to start unlock the car but don't open the door. Reach in with a stick to press the brake and press start. Then get in. Would that work? Or does the driver door need opening before the car will start?

Auris hybrid behaviour is exactly the same. Perhaps your idea may work but it’s a lot of hassle. I usually use the passenger side if I need to take something from the car while parked and doing so avoiding Battery drain. Also turn off interior lights if not driving at night because I walk around the car with key in my pocket. No need to stress much about anything we do with these cars become if the Battery is ok and we do use them even once a week for 30+ min or in ready mode we won’t have any problems. 

[CPN]

Thanks for all the replies thus far.

One thing that I didn't mention was that we got caught up in yesterday's A1 debacle between junctions 45-48 plus 7-8 miles of queuing traffic before, lasting some 2 hours of crawling along. We were forced off at the Wetherby turn off onto the A168 and had to stay on it until Boroughbridge in an enormous snake crawling along at no more than 15-20 mph. Sometime during this was when I first noticed the drop in the HUD display. Then the rest of the problems when we arrived at the filling station as before...

I wonder if any of that had any bearing? I'm definitely going to check all the earth straps and the Battery terminals.

[MikeSh]

1 hour ago, TonyHSD said:

but it’s a lot of hassle

Quite so. It was just a suggestion for the time between the Battery starting to play up and replacing it to lessen the chance of it refusing to get into ready mode.

Passenger door is another option unless it's not accessible ... mine is inches from the garage wall at home.

[CPN]

Take a bow all those that suggested I check the Battery terminals! Problem found and fixed!! 😁

It was the earth post (-ve) clamp. It would seem that when I installed my CTEK extension cable (eyelets) a couple of months ago, I was a bit conservative with the tightness of the nut and it would seem, several hard jolts over potholes later, that it had slowly rode up the post to the point where I could turn the whole thing easily by hand!

Made sure it was good and tight with a socket this time and just for good measure checked the positive post too after disconnecting it completely for at least 30 seconds so that everything had a good "reset".

Once back on, checked all the ECUs with Carista again and all was good including the operation of the right rear passenger window.

 

I must say that the window thing was pretty random considering all else! 🤪

Thanks for the pointers guys. 🙂

[TonyHSD]

I am glad it’s all sorted.
38 ECU’s scanned, in comparison to Auris from 2010 with only 21 ECU’s, almost double,  just my attention to details 😂🫢👌

[CPN]

24 minutes ago, TonyHSD said:

I am glad it’s all sorted.

I'm somewhat relieved it was nothing more serious also!

24 minutes ago, TonyHSD said:

38 ECU’s scanned, in comparison to Auris from 2010 with only 21 ECU’s, almost double,  just my attention to details 😂🫢👌

Lol! There is actually 42 if you use Techstream but Carista's app doesn't seem to know about the other 4 for some reason...

[flash22]

Low voltage will freak out electronics a resting voltage is fine but as the current rises the voltage drops anything below 9v and you're in trouble

[Derek.w]

Hi Colin I am glad you picked up the fault of loose Battery post clamp before buying a new Battery.

[Cyker]

Well at least most of us were close with suspecting it was battery-related, but blue peter badges for everyone who guessed the terminal post specifically!  

And good on CPN for actually checking that!!

[CPN]

15 minutes ago, Cyker said:

Well at least most of us were close with suspecting it was battery-related, but blue peter badges for everyone who guessed the terminal post specifically!  

And good on CPN for actually checking that!!

What is even more of a shocker is that I bought that CTEK extension cable back in November 2021 and would have fitted it then. So, it has taken a period of 18 months of driving to work loose!! I mostly manage to drive around bad potholes but I do remember a couple of really bad ones over the last 3 months where I was blind-sided by the vehicle in front and didn't spot them quickly enough. The thud as I hit them down the right side of the car was very disturbing. So much so that I made a visit to the dealer (primarily to change to my summer tyres) and asked them to do a thorough check of the wheel alignment and if any damage had been done.

I watched him do it through the viewing window and he was very thorough and the answer to both of those questions was a relieving "no". Who would have guessed that something like that would have shaken that terminal loose though? It's not like I purposely left them less than tightened! I guess there is always a potential for that to happen with a tapered Battery post...

[Cyker]

I wonder if I should add checking the Battery posts to my checks, given how many potholes and stuff I go over regularly!  

 

[CPN]

Probably not a bad idea given that it's relatively easy to do...

[CPN]

...and the icing on the cake?

Looks like the Battery likes the tighter connection too! Took the Battery off overnight charge at 03.45pm and it was...

  ... 1hr later it was... 

That is a good sign of rude health in the Battery! (that it rose at rest) 😁

[CPN]

@Cyker go wash your dirty mind! 🤣🤣

[Yugguy1970]

On 7/8/2023 at 6:08 PM, CPN said:

 

Once back on, checked all the ECUs with Carista again and all was good including the operation of the right rear passenger window.

 

Howdo, would you say the carista was a good buy, the adapter seems cheap enough but a tenner a month, or basically every time you have an issue seems a lot.

[TonyHSD]

1 hour ago, Yugguy1970 said:

Howdo, would you say the carista was a good buy, the adapter seems cheap enough but a tenner a month, or basically every time you have an issue seems a lot.

But if you buy a year subscription will cost less than £4 per month, not bad considering the dealer will charge excess of £100 just to run a diagnostic. Then you have a freedom to do your own diagnostic checks , Battery tests, some personal settings , I think it’s worth it.
I usually buy a subscription for one year after I had a problem with the car and then cancel the renewal and subscribe again after I have another problem, that’s  the cheapest way for me. You can use t(w adapter with other apps on android or iOS. 👍

[CPN]

2 hours ago, TonyHSD said:

But if you buy a year subscription will cost less than £4 per month, not bad considering the dealer will charge excess of £100 just to run a diagnostic. Then you have a freedom to do your own diagnostic checks , battery tests, some personal settings , I think it’s worth it.
I usually buy a subscription for one year after I had a problem with the car and then cancel the renewal and subscribe again after I have another problem, that’s  the cheapest way for me. You can use t(w adapter with other apps on android or iOS. 👍

Exactly what Tony just said!

(also, I did buy the Carista adapter a few years back but I ended up with the OBDLink Mx because it is way better and the Carista app works fine with it anyway)

[CPN]

4 hours ago, Yugguy1970 said:

Howdo, would you say the carista was a good buy, the adapter seems cheap enough but a tenner a month, or basically every time you have an issue seems a lot.

See ^^^ above

[Yugguy1970]

Cheers all and daft question I know but I guess this would work on any modern Toyota?