S4 tantrum

Big of a long one here for anyone who can be bothered, but I figure it's better to have too much than too little info. Apologies in advance.

My S4 B8.5 has been running great...until this afternoon. At lunch time I get in, turn on the ignition when starting the car basically shat out a list of error messages which would rival a Jaguar. I turn Karen off and restart but the same thing happens, a huge amount of errors followed by copious sweating by me as I start imagining the worst. Thankfully it still drives, so I can still get home to my Pot Noodle.

Once home I calm down with a Bombay Bad Boy (King Size of course) and I start having a think. I remember that on Sunday when checking my dashcam for some footage that it didn't cut off after 2 hours parking as per my settings with my beloved Vico Battery Protect and it has been recording solid until today. I'm guessing my battery has been assaulted and I remember from my Jaguar ownership that a dying battery is usually the prime suspect behind such a random list of errors.

I double check my Vico unit and it's still set correctly so maybe after about seven years of faultless use it could be failing and not switching off after two hours. I pop my OBD2 fuse back in and hook up my Autel code reader dongle and start reading all the Audi modules. It's error galore from a variety modules, so unless my car has suddenly had a stroke then this has got to be the battery.

I do an auto error erase and it starts working through the modules, but the first two throw up errors again. The rest all clear and don't return. I try again and now everything disappears and doesn't return - but, I've been idling for a while so I figure my battery will be charged up a bit.

The type of errors coming up on the dash were things like stability control, parking brake, headlight auto adjusters etc. I can list all the error codes from the scan but they've gone now and I've not started the car back up since as I'm too busy at work. Also, I noticed one of the error codes was for the front left ABS wheel speed sensor (although it has cleared for now) and I mind that with Jaguar a faulty ABS sensor can also throw up lots of codes. I think the wheel bearing was previously replaced on this wheel as well.

My next step before I rush off and buy a battery or something is to see if the dash cam is now switching off after two hours since I reset it all, if not then I'll remove the switching fused connection so that it only comes on with the engine and then see how things go. I'll go out for a long drive as well to give the battery a good charge. I was wondering if anyone else has had a similar experience with a weak battery causing all these errors? The battery will be in its sixth year but start/stop works perfectly (I don't use it but sometimes forget to turn off) so I'm guessing it is still healthy? Or could it be the ABS sensor?

Many thanks in advance for anyone who bothered to read through all this, it was a bit of a scare after only having the car a few months.

Thanks for the replies. I've gone out for a long drive and got the battery to 92% charge but the codes won't clear now. It's also saying my battery is still at 62% of it's lifespan.

I'm now thinking about that ABS sensor. That code hasn't appeared again but there is a brake system error code showing. The roads are ****** awful so maybe a bad bump has damaged the sensor?

I'm going to save the error report and start researching. The warnings showing on the dash in order are:

Stabilisation control failure
Parking brake malfunction
Tyre pressure system malfunction
Headlight range control defective

And the relevant icons also appear. My traction control button doesn't work now. The car seems to drive fine except that I have no ABS. I had to brake sharp and I locked up.

JohnS3 said:

These are classic signs of energy management issues.

Stabilisation control failure
Parking brake malfunction
Tyre pressure system malfunction
Headlight range control defective

I’d be looking at a new battery. (And did so 6 months ago, problems gone)

Post a full scan and we can take a look.

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I'm really hoping it's just the battery. I'll need to see what battery mine takes as I don't always trust the online databases. I've also noticed that the steering wheel doesn't lock now when you remove the key.

Here's the report, I think I'll start with the battery as there's no harm replacing it anyway and then see what happens. Is there anything important I should know before changing the battery such as does it need to be coded or reset?


Thanks again.

Found a few references and I hope it's not the ECU box.


One thing is that I mind seeing an error for the front left ABS sensor which seems to have gone now. However, when I was getting my s/c and aux belts done at the local Audi indy last week I asked them to check my suspension as I knew there was something not quite right. They came back saying the front lower arms had a lot of movement and needed replacing.

Looking at that last link, I'm wondering if it possible they may have damaged the ABS wiring whilst checking out the arms, presumably with a tyre iron or such? Seems a little bit of a coincidence for this to happen so soon after being in there as nothing else has been touched since.

JohnS3 said:

I was expecting a scan from VCDS. That one you posted doesn’t show all the modules in the car. For example 03 ABS brakes is not shown and module 16 steering is telling you to look at the error codes in the brake module. A9 structure born sound (sound actuator) is also missing.

You say start/stop still works?

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I don't have VCDS I'm afraid, I don't even know how or exactly what to get with VCDS? I'm very new to Audi (and hoping I'm not going to regret it!). Is this all I need to buy as it says it unlocks the software as well: link

Stop/Start works, but I've not tried it since this problem came about today. Went for a long motorway drive without any problems, car seemed to drive like normal except for lack of ABS. I wasn't cornering hard or anything but I did do a few blips of acceleration and all was good.

I've got icarsoft as well with the Audi module, I'll try that tomorrow to see if it reads more modules.

Glad I kept my icarsoft. I think I'll start with this sensor and see what happens. Will inspect it first as I suspect Audi will want a pretty penny for a new one. Thanks so far, got everything crossed that it's this simple.

Edit: £105 at Audi or £25 for Bosch from Dingbro. For £25 I'll just replace it straight away rather than mess about inspecting first.

Headed into work just now and everything just cleared lol wtf? It is roasting outside though, maybe something has dried.

Autel now reading the front nearside ABS sensor, which is rather specific. I've managed to clear it all but I'm sure it will return.

Battery is 12.5V but drops to 12.2V within 30 seconds. I think that will be next on the list.

Damn thing is dug in like an alabama tick and when gently prying at the base I could hear the plastic start to break. Light is fading so going to get it in the garage tomorrow and prepare to drill it out.

Everything looks pretty decent so I'm surprised at it being stuck.

Well that turned into a pig of a job.

It did snap as expected so we ended up drilling away. The sensor was in there insanely tight, so much so that it wasn't until the last skinny part was left that a self tapping screw was then able to pull the remains out. Was worried about drilling too far or bits of plastic getting lost.

The new one was tight to go in despite the hole being clear and the sensor being lubed, I'm not sure why it needs to be so tight considering it's screwed down with a hex bolt. Anyway, now that it's connected the warnings are all gone.

£28 and 1. 5 hours work, so a few bottles of Amarone, I'm delighted with that.

JohnS3 said:

Yes, You need a PC running windows too.

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Thanks, I will probably use my laptop for this as it hardly gets used for anything else.

Nicked the brake pad wear sensor whilst in there and the brake disc retaining screw was rounded so that needed drilling out as well. Sorted it all this morning so now all that's left is the front lower and and apparently my exhaust hangers are in need of replacement. Then a full alignment and the car is mint.

I just noticed that this thread title might be taken as me having a tantrum at the car when I actually meant it was the car having a tantrum!