# 01435, Brake Pressure Sensor 1(G201),008 Implausable signal



## DC240S (Sep 24, 2014)

Hi all,

ESP light has come on and a fault code scan revealed: 01435, Brake Pressure Sensor 1(G201),008 Implausible signal

Checked the brake lights and they work. I had my brake fluid changed at Audi a 100 miles ago, I changed the discs/pads - with no prior faults/ESP warnings.

Could the fluid change have any connection?

Cheers,

DC


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## jamman (May 6, 2002)

http://wiki.ross-tech.com/wiki/index.php/01435


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## DC240S (Sep 24, 2014)

Thanks for the info.

Been for a drive and the lights off again - will have to see how goes.

DC


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## Skeee (Jun 9, 2009)

DC240S said:


> ....................
> Could the fluid change have any connection? .........................


 Was an abs bleed done as part of the fluid change? For the full ABS bleed the car has to have all 4 wheels off the ground and be plugged into vagcom/VCDS.

If you have (legal) access to a safe grassy field you can "pump" the new fluid through the ABS pump yourself. :wink:

It could be the fluid but my guess (I read a little about this previously) is it's most likely one of the two pressure sensors (G201, G214) which on your ABS model (Teves Mk60) are under the Brake Master Cylinder.

There are some reports of the The Mk20 system (pre2003) failing with this code because of an electrical problem in the ABS Unit itself.

To confirm it is the sensors have a look each sensors pressure level output when they are cold and warm. I think the tolerance is plus/minus 5 (bar) but it will be obvious. 
When the brake pedal is released they should both be zero or around +/- 0.1 bar rising approximately together to either 30~40 or 50~60 bar depending how aggressive you are with the pedal!

Sensors cost 80 something each, common to do them as a pair.

Do a forum search for* G201 *and* G214 * as I've posted a little about this before.

IIRC sensor outputs are in the ABS Measuing Blocks (MVB) values 3, 4 or 5.


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## Skeee (Jun 9, 2009)

DC240S said:


> Thanks for the info.
> 
> Been for a drive and the lights off again - will have to see how goes.
> 
> DC


When mine failed, it was only out of tolerance as it got warm. So pumping the abs, or parking up for an hour or so would clear the fault.

Edit- if it comes bark, start with the obvious and check the plugs are secure. 
You can see them from underneath and maybe just reach them with your fingertips!!


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## DC240S (Sep 24, 2014)

Thanks for all this advice/info.

I don't know if an ABS bleed was done using vagcom/VCDS as described. Would this be an expected practice as part of the brake fluid service at the Audi dealership? I've asked the question at the dealer and I am waiting a reply.
I do know that I was told none of the wheels were removed which I found odd?

Unfortunately I don't have vagcom/VCDS to test each sensors pressure level output. Should this not be done during an ABS bleed as a precaution?

DC


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## Skeee (Jun 9, 2009)

DC240S said:


> Thanks for all this advice/info.
> 
> I don't know if an ABS bleed was done using vagcom/VCDS as described. Would this be an expected practice as part of the brake fluid service at the Audi dealership? I've asked the question at the dealer and I am waiting a reply.
> * Dealerships will charge extra to bleed the ABS, I was quoted £50 extra, but both my local indies did as part of the fluid change.
> ...


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## Domo86 (Jan 11, 2020)

How did this go in the end?? Having similar fault code g201 but seems that it is inside the mk60 rather than the earlier mk20 as apposed to what skee is saying above.


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## DC240S (Sep 24, 2014)

Domo86 said:


> How did this go in the end?? Having similar fault code g201 but seems that it is inside the mk60 rather than the earlier mk20 as apposed to what skee is saying above.


I replaced both sensors myself - saving a quoted £500 approx.

I provided some details in my build thread here:

https://www.ttforum.co.uk/forum/viewtop ... &start=675


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## Colin1s (11 mo ago)

I'm trying to find the procedure you used to move the master cylinder to replace G201 and G214 Sensors. I'm having a bit of a nightmare trying to figure out how to DIY the job. Already spent £400 at an independant Audi specialist. They said pins at the ABS had to be replaced and frankly that doesn't fit with the VAG readings I have which point to the sensors. Tomorrow I will confirm that with a friend in the car using measuring blocks while I drive (I.e. the ESP light comes on intermittantly while driving. Can be in a straight line without touching brakes.).


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## silverbug (Jan 1, 2020)

Using VCDS you can check the pressure readings being declared by each sensor at rest with foot on brake pedal…..so no need even for a road test, both sensors should have very similar pressure readings.
When I did the job there was a great thread by DC240S that I followed, will see if I can find it, think it’s in his quattro Sport build thread….

Its buried in here, page 40 of his thread.









Anyone here changed their G201/G214 brake pressure sensors?


So it looks as if my brake pressure sensor(s) on the master cylinder are playing up. The ESP light came on last week and after scanning it with VCDS the code P01435 Brake Pressure sensor 1 (G201) Intermittent electrical fault was found. Having checked the measuring blocks for the G201 switch the...




www.ttforum.co.uk





I didn’t remove the master cylinder reservoir when I did mine, access to the sensors is very limited and I wasn’t able to get a crows foot wrench in there to tighten up the new sensors to the correct torque so had to “guesstimate” how tight to do them up.
It really wasn’t that bad a job to do.


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## fire88 (Jul 15, 2021)

I have done it with master cylinder removed which gives better space and also cleaned it properly.

it's not that hard job depends on your tools and how handy.


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## Emsworthy (10 mo ago)

Just about to embark on this task myself. Quick question. Why does the clutch need bleeding afterwards? I totally get why the brake circuit does, as the sensors sit in the loop but as I understand it the clutch has its own reservoir and MC and just uses a gravity feed from the brake reservoir to keep the system topped up. If that’s the case then surely the clutch circuit has not been broken and no air can have been introduced?


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