Red (!) Warning light on

[Jack4688]

My auto check warning light came on intermittently the other day so I checked fluid levels. The only thing that looked under the min level was the header tank, so I topped it up. I noticed the power steering reservoir and oil level were low, but not under the min level.

The light came on again yesterday so I added some more oil and power steering fluid in the hope it would go away. Each time it had come on it was only for a few seconds but this morning it came on upon start up and stayed on. I stopped at Tesco before getting to work and switching the car off and sitting for a few minutes didn't reset it (which has happened with me in the past).

I press the brake pedal when I start out of habit now - to make the light warning go away - and I noticed the pedal felt a bit soft. I had the clutch replaced along with the gearbox in Feb and recently noticed a 'chirrup' noise when fully depressed. These are the only things I can think of that might have anything to do with it, but is there anything I'm missing? Does the (!) warning have much more to do with than just fluid levels?

[Christophski]

Take the PS fluid cap off and soak it in some cleaner and gently with a soft brush try cleaning the sensor nipple as sometimes this sticks down slightly causing the warning to appear.

[Jack4688]

I'll try that first thanks will some degreaser do the trick? I've got plenty of that here at work

[Christophski]

Umm... havent got a clue mate.

Be careful as the nipple on the outside of the cap bends easily. You want it to move really easily

[Jack4688]

Is the sensor nipple within the cap? The plunger (for lack of a better word) looks clean as a whistle so I'm not sure PAS fluid level is the reason for the (!)

[bluequattro]

Pas pump sound ok? Could be that or a failing bomb from my experience as the pump pressurises the bomb
Do a pump test on the pedal, search the forum as I can't remember how many pumps to check them
Have you been using correct pas fluid? They don't like the pink stuff

[Jack4688]

I replaced the pump in December, sounds OK at the moment I use central hydraulic fluid, that's correct right?

Pumping the pedal changed nothing - it remained soft-ish. Holding the pedal down as far as I could then starting the engine also resulted in no change surely the pedal should then go down much further as I gain servo assistance?

But here's the other thing, no (!) warning light Only difference from earlier today being I filled the tank having been almost dry am now parked on an incline, nose down - over the weekend I had the car on the front drive, nose up and at work I park on the level.

Having sat in the car with the engine running just now has made me want to go out for a drive so I'll go out and do some more investigation

[Jack4688]

So after a drive last night and to work this morning it's not gone away. Though not as bad as it was yesterday when it was on for the duration of my drive to work, it did come on a couple of times today. The power steering is definitely not making any noises so do we think it's the bomb?

[UrS4boy]

So after a drive last night and to work this morning it's not gone away. Though not as bad as it was yesterday when it was on for the duration of my drive to work, it did come on a couple of times today. The power steering is definitely not making any noises so do we think it's the bomb?

As of a few days ago, my 94 S4 V8 avant is throwing out this code. Oddly it started when I was messing with the aftermarket 3rd brakelight that was added when the car was imported into Canada in 2010. It doesn't come on until I make my first left turn and then it only stays on for maybe 15 seconds. Today, I checked the fluid level in the tandem pump Pentosin reservoir (fine) and I removed the level warning switch and cleaned it up and its harness connections. If it doesn't go away, I am going to clean the connections to the pressure switch on the brake servo.

Item 4 here (PN 443919081):



The connectors are the "24"s near the brake master cylinder and the BPS (brake pressure switch) here:

[UrS4boy]

As of a few days ago, my 94 S4 V8 avant is throwing out this code. Oddly it started when I was messing with the aftermarket 3rd brakelight that was added when the car was imported into Canada in 2010. It doesn't come on until I make my first left turn and then it only stays on for maybe 15 seconds. Today, I checked the fluid level in the tandem pump Pentosin reservoir (fine) and I removed the level warning switch and cleaned it up and its harness connections. If it doesn't go away, I am going to clean the connections to the pressure switch on the brake servo.

Just a follow-up. I did remove and clean the level float switch. Didn't solve the problem. Showed up again ((!)) in red the next morning. Then I bought a green can (1L) of the CH11 green Pentosin PS/PB system fluid. And the issue is gone (I hope - two days now).

The trick is I never put any of the fluid into the car. I just bought it. I presume that the car (94 S4 V8 avant)) just was feeling unloved and was crying out for attention (which it got lots of yesterday).

[Jack4688]

Well that's no help to me - my car gets plenty of love from me! And I always tell it that it's got much better personality than the younger, better looking cars on the road (which aren't actually better looking than mine )

[UrS4boy]

Well that's no help to me - my car gets plenty of love from me! And I always tell it that it's got much better personality than the younger, better looking cars on the road (which aren't actually better looking than mine )

Sorry about that. In that case, I suggest clecking and cleaning the PS/PB fluid level switch and also the two single connectors that connect to the high pressure switch on the brake servo (Item 2 below):

[Gold top]

hi jack, I had the same warning intermittently.
Thought oh **** what's this going to be now, and i imagened the price it might come to at Audi.
Anyway.... MOT was due and a local garage was advertising cheap mots and vag diagnostics. So I booked it in.
On the morning of MOT I gave my s2 a quick check over for bulbs etc, and noticed the rear lights were not too bright on one side, quickly stripped of rear bulb holder etc and cleaned off some corrosion etc WD40ed it all up, lights were sorted.
Set off to MOT and no warning lights etc but didn't for a minuite think I'd sorted it.
Guy at MOT garage reported NO codes or faults + a pass
Warnings have never ever ever come on again since.

Hope yours is a simple fix too, all the best.

[Guslotti]

Check the pressure reservoir. Maybe the problem is there.

[Jack4688]

Sounds like I've got a lot of cleaning to do!