Hi folks,

 

My 2012 mk2 Fabia's brake system warning light comes on after a few seconds of starting the car (three beeps, and the ((!)) light).

 

According to the manual, this light means either the fluid level is low, or there is a problem with the ABS (if accompanied by the ABS warning light). The ABS light does not come on.

 

The brake fluid levels if fine. If I disconnect the level sensor, the warning light goes off/doesn't come on.

 

My model has a separate handbrake warning light, that warns if the handbrake is on.

 

Any ideas?

 

Does the circuit with the sensor on have anything else on it that could be causing the problem? Can the sensor be replaced?

 

Thanks!

 

Jake

I've never ever had any trouble with a VW Group car brake fluid level sensor, but I'd think that it is just a float switch.

So, if that is correct, after disconnecting the connector, remove the cover-sensor assembly and connect a DVM across the connector pins and see if moving the float fully up and fully down changes the state of the circuit through the sensor contacts, if it doesn't then you need a new cover-sensor.

Not sure anything else is on this circuit but a friends car had an issue the same and it was a faulty cap, when we broke it apart there was +a brass type ring that had come off the plastic and was resting on the contacts allowing the circuit to complete, one used cap from a breakers later and problem solved, if it's getting on your nerves you can always pull one of the wires off and just keep a eye on the level like we all did for many years before fancy lights came out

Thanks for your replies.

 

It's a bit annoying that the sensor is built in to the reservoir, not the cap, so is harder to get at and test.

 

My brother suggested that I buy a reservoir with sensor, and plug this in to see if that solves/reproduces the problem.

 

If there's nothing else that it can be warning me of, then I'd be reasonably happy to unplug and just keep an eye on the level. I just didn't want to have got the diagnosis wrong, and later have a catastrophic failure due to something completely different. 

I would monitor it as you say, and find a second hand one on Ebay to replaced it with.

5 hours ago, JakeR said:

Thanks for your replies.

 

It's a bit annoying that the sensor is built in to the reservoir, not the cap, so is harder to get at and test.

 

My brother suggested that I buy a reservoir with sensor, and plug this in to see if that solves/reproduces the problem.

 

If there's nothing else that it can be warning me of, then I'd be reasonably happy to unplug and just keep an eye on the level. I just didn't want to have got the diagnosis wrong, and later have a catastrophic failure due to something completely different. 

 

Oh, that is not good, so the sensor is in the reservoir, bother that!

My new (used) brake fluid reservoir/master cylinder arrived.

 

Plugging it in to the sensor cable (instead of the in situ one) causes the warning light to come on if upright, and go off if I flip it over.

 

So this seems to confirm that the sensor is the problem (since the in situ reservoir has plenty of fluid).

 

Does anyone know if it's possible to replace just the reservoir? The sensor is bonded in to it...

Have a look at this parts diagram brake master cylinder; reservoir - Fabia(FAB) [EUROPA 2012 year] (7zap.com)

 

The reservoir pushes in to 2 rubber bungs mounted in the Master Cylinder.

 

There is a screw through the MC that screws into the reservoir which will need to be removed. Part  No 2.

Then just lever up the reservoir.

Best if you siphon out as much brake fluid as you can first & have rags underneath to catch the rest.

Successfully swapped out the duff reservoir/sensor this morning. Pumped out as much fluid as I could using an old soap dispenser thing, undid the hose to the clutch, and popped off the reservoir. New one popped in easily. Even remembered to replace the retaining screw!

 

Don't think I introduced any bubbles, but gave everything a jiggle anyway.

 

Checked the old sensor with a multimeter, and it is indeed stuck such that the circuit is made whichever way up it was.

 

Altogether pretty pleased with myself! 

Excellent result !! Nothing like fixing a fault yourself.    Just imagine how much that would have cost at a dealers with new parts !!