Air con faults

[quattromark]

I'm out of ideas with this -

The output of the climate control unit (C1) is connected to the blower unit for speed control and also to the AC temp/pressure sensor - The connection is a LIN signal.
The speed control of the blower works fine - the AC pressure temp sensor shows no signal/communication in VCDS.
The line from the pressure sensor to the climate control has continuity as does the connection to the blower motor - This connection parallels in a connector in the ECU box.

The AC pressure sensor shows 51 BAR in VCDS.....it shows the same if I disconnect the sensor!! -
I'm thinking that the new (from Audi) sensor is faulty...

[Crasher]

51 Bar, I didn’t know it could read that high, I don’t see it being the sensor.

[quattromark]

51 Bar, I didn’t know it could read that high, I don’t see it being the sensor.

Well this is my point.... there is no way ANY sensor on ANY car would have / need to measure 51 BAR - thats about 740 psi ...... maybe auto gearbox???

anyway.. my point... if the sensor is short/open circuit.... what does it show - is it 0 or 51 BAR- I am REALLY hoping that the sensor is faulty......irrelevant of whether that sensor is connected or not - vcds shows 51 BAR - so is the sensor open circuit?
It would be really good if someone with an A6C64F could pull the connector on the AC..... however considering the front end has to come off and then AC measured with VCDS, I'm not holding out for many takers!!!!

So, as a proving point - I have ordered ANOTHER sensor from Amazon - will be with me Sunday......lets see what happens.........

[Crasher]

Well this is my point.... there is no way ANY sensor on ANY car would have / need to measure 51 BAR - thats about 740 psi ...... maybe auto gearbox???

VAG common rail Diesel engines routinely operate at 2000 bar (circa 29000 psi) and some are in the 2800 bar range.

[quattromark]

Well this is my point.... there is no way ANY sensor on ANY car would have / need to measure 51 BAR - thats about 740 psi ...... maybe auto gearbox???

anyway.. my point... if the sensor is short/open circuit.... what does it show - is it 0 or 51 BAR- I am REALLY hoping that the sensor is faulty......irrelevant of whether that sensor is connected or not - vcds shows 51 BAR - so is the sensor open circuit?
It would be really good if someone with an A6C64F could pull the connector on the AC..... however considering the front end has to come off and then AC measured with VCDS, I'm not holding out for many takers!!!!

So, as a proving point - I have ordered ANOTHER sensor from Amazon - will be with me Sunday......lets see what happens.........

Well, new sensor fitted - no change ( not really surprised).

The climate control unit is displaying this fault in VCDS.

01087 - Basic Setting Not Performed
005 - No or Incorrect Basic Setting / Adaptation
Freeze Frame:
Fault Status: 01100101
Fault Priority: 2
Fault Frequency: 1
Reset counter: 231
Mileage: 358911 km
Time Indication: 0
Date: 2023.10.29
Time: 17:10:35

However, it has been showing this for 2 years - but oddly enough it will not let me perform a basic setting on it - fails everytime.

My next step is to get the CP removed from my spare Climate control unit and see where we go from there.

[dan2485]

You may need to do the addressing in the Basic settings as it may not recognise the new sensor, then try again.

[quattromark]

Well, I hate to admit this but I'm out of ideas!

I have spent all day looking for this air quality sensor - I know a lot of people don't bother with them as all it does is activate the re circ flap, however, I'm not sure how this interacts with the AC pressure/temp sensor.
According to the drawings I have, the air quality and pressure sensor are not connected - they have individual inputs to the climate control unit..........HOWEVER, I have been legged up with these drawings before.
It is possible that the air quality sensor is messing up the LIN signal if indeed they are joined......Its a shame I can't find it.

I have removed the blower motor box completely- Air quality sensor (or wiring) no where to be seen - I found the air temp sensor inside, but thats it!
Also removed A LOT of the dash so I could see which of the flap actuators were faulty so I can get them replaced.....Again, found temp sensors but no air quality sensor.

I'll have a look at ERWIN when I get time this week and probs print the wiring diagrams from it - just in case mine aren't correct.

[Crasher]

I find it odd the sensor isn’t there but I can’t see it causing the problem.

[quattromark]

So after subscribing to erWIN it turns out that I do have the correct diagrams after all -

What I did notice however, was that on the parts page for the AC, it shows the Basic AC climate control unit for my car, not the all singing flashing controller that I have fitted - I think its called the 'convenience' package - which incidentally the Air quality sensor is marked as being part of - Now I'm thinking that I don't have a sensor because I have the basic package/controller which the sensor is not part of. Could the controller have been retrofitted by previous owner?
Anyways, It does not matter - just want my aircon fixed - going to see if my tame Audi parts dept will exchange the genuine pressure sensor I bought for another unit just in case it is faulty.