Goddammed warning symbol!!

[Paulgo]

As part of a process of elimination to finally eradicate the cause of the dreaded (!) symbol and three annoying beeps Im going to try swapping the brake fluid reservoir/tank. I think there’s a float in there which can cause problems. I know the tank basically plugs into two grommeted holes on top of the master cylinder and can be pulled off. Other than draining the excess fluid out of the tank is there anything to look out for? Also will I need to bleed the brakes afterwards?

The warning symbol seems to be level related. Sharp movement, or even just pulling away will set it off and it’s the bane of my life! Been on the car since I bought it and never got to the bottom of it. I know the bomb is good as it takes a about 50 or so pumps for the pedal to go hard. I’ve swapped and cleaned the float / cap on the power steering pump reservoir to no avail. Even totally unplugging it seemed to make no difference either. Same with the little grey sensor under the brake fluid reservoir. Swapped that for a spare and it made no difference, as did totally disconnecting it. Ive just swapped the two pin brass sensor that’s tucked away right under the master cylinder - no difference. The warning light normally comes on about two seconds after I pull away. Sometimes later, but usually not much Admittedly, I not used brand new replacement bits and I could just be that unlucky – and I will buy new if the tank doesn’t work.

I could still have the levels themselves wrong. Its not that easy to judge what the correct level for the power steering fluid should be in the tank – the level mark is hidden and is that level supposed to be with the tube-like filter housing in? Brake fluid to be honest should be changed as its been in probably too long, but it must be a sensor of some sort

Paul.

[Jamo]

The bomb test is not fool proof. My old bomb used to pass the test and until I changed it I got the warning

[Fat Audi 80]

I agree with Jamo. If you are only getting on start up then it is likely to be the bomb bleeding enough pressure away while parked up. Mine has done it since I bought the car 4 and a half years ago. Mine also passes the bomb "test" with about 50 - 60 pumps.

( I can't be bothered to buy a new bomb and replace it, which I know is the only cure...!)

If, however it is doing it intermittently while you are driving that is a different matter altogether!

HTH

Cheers,

Steve

[Jamo]

Mine got really bad, if I broke medium to hard the warning symbol would come on the dash it was quite scary!

[GazzaG60]

you dont want it to fail do you.

my light comes on when i brake hard sometimes but that the stupid shape reservoir and being a fraction low.

top it up a little further. even a couple of mm below the line wityh the movement can be enough to beep-beep

[Christophski]

My light came on a load in cornering, pulling away sometimes and even going over bumps so I filled up power steering and brake reservoirs over the markers, maybe not the best to do but it got rid of the annoying symbol! If u try this and it continues u can always sypher some out really easily to put the levels back down

[Paulgo]

cheers guys - its completely random, corners, turning, can be just about anything like that and at different times - so not just pulling away. Just did it heading home going over a speed bump. Its usually movement related and not connected with braking in that respect which is why Ive not thought too closely about the bomb - but you never can rule that out I guess. I will try topping up the levels a little - you never know!

[Quattro Ayes]

Can it make the warning if the brakes are too worn?

[Fat Audi 80]

Check the wiring on the cap of the power steering reservoir. If you move mine to the wrong position it does (!) all the time randomly.

Worth a try.

HTH

Cheers,

Steve.

[Mikes2]

Almost certainly not the reservoir.

I had this on my 90q 20v and the warning came on before starting the engine and it stayed on constantly.

It's a good test to turn on the ignition and not start the engine. If you get the warning, it's a level problem. If it doesn't come on until you start up - it's a pressure problem

[johne]

Almost certainly not the reservoir.

I had this on my 90q 20v and the warning came on before starting the engine and it stayed on constantly.

It's a good test to turn on the ignition and not start the engine. If you get the warning, it's a level problem. If it doesn't come on until you start up - it's a pressure problem

I disagree, based on my experience, it certainly could be the brake fluid reservoir level sensor playing up but there's any easy way to check without having to change it. Just disconnect the plug from the sensor and if your random triggerings go away you know it's that sensor.

I had the same problem and solved it by leaving the plug off permantently.

John

[gedu]

Also "bomb-error" can be checked with disconnecting wiring. At least in LHD UrS4 servo pressure sensor is in servo. Just disconnect wires from servo and it wont yell at you when bomb is gone.

How do I know this? I quite like my bad bomb and heavy brake pedal, but MOT engineer doesn't like red warninglights and loud sounds

[Jamo]

It could also be the PAS pump being worn and not supplying enough pressure

[steve1234]

i had this annoying sound and symbol

it turned out to be the seal gone on the clutch master cylinder and was weeping brake fluid into the footwell. It might be worth checking if you have any fluid deposited under the mat! it wasnt very noticeable until i lifted the matt and the carpet was drenched. Are losing a lot of fluid and having to top up constantly??? Its a bit of a long shot but i thought i would share the experience of owning the wonderful S2.

[Paulgo]

Thanks for the responses guys. (Topping up the levels made no difference )

It's a good test to turn on the ignition and not start the engine. If you get the warning, it's a level problem. If it doesn't come on until you start up - it's a pressure problem

That a really good tip Mike – I’ll give that a try. I cant say I’ve ever noticed it do it just on ignition / autocheck, or even when the engine is running and the car it stationary. It only seems to be when the car is moving – but will check that again tonight. Also it doesn’t always clear if I re-- start the car after a short time. Had to get some petrol this morning and it was still on when I drove away.

Check the wiring on the cap of the power steering reservoir. If you move mine to the wrong position it does (!) all the time randomly

I have had a problem with one of the wires coming off the connector to the cap – sheared at the tail of the spade connector, probably from the amount of times I had the booger on & off. When I discovered that I thought “Ah-ha!”. Soldered a short bridging length of wire to the connector to patch it up - but it made no difference. It could be more sensitive than I think tho and interesting to see that was the cause of your very similar problems, so worth having another look and possibly improve the repair!

it certainly could be the brake fluid reservoir level sensor playing up but there's any easy way to check without having to change it. Just disconnect the plug from the sensor and if your random triggerings go away you know it's that sensor. I had the same problem and solved it by leaving the plug off permantently

I’ve done the same but it made no difference, perhaps made it a little worse. Which is why I was thinking that changing the tank might not solve the problem as the float must send its info via the little grey sensor that lives in a slot underneath and the connector. (I will recheck the wiring to the connector tho!) I don’t think the sensor costs a fortune from Audi so will probably invest in one of those anyway. I actually thought that disconnecting it would permanently trigger the alarm, which it didn’t, but it unfortunately it didn’t make it go away!

Thinking about things logically - and from the comments above - although everything to me seemed to point to a sensor playing up over levels (as its triggered by some form of change in movement or just movement of the car itself, rather than braking necessarily) I seem to have ruled out most of the culprits one way or another. Messing around with the brake and power steering reservoirs and sensors appears to make no difference. I recently changed the PAS pump so I doubt it’s that and there's no evidence of any fluid leaks that I can see such as Steve suggested – levels, certainly brake fluid, are fine.

So – and especially after Mikes suggested test - that brings me back to a pressure issue which I’m assuming can only have the bomb as the root cause? Are there any other sensors that I’ve missed?

Cheers

Paul.