AC shut off Need help with Codes

[bberg22]

Hi all,

So this morning it was raining pretty heavily and once i got off the highway after about a 30 mile highway commute, i noticed my windows start to fog up. I thought "thats weird, they usually don't do that" but didn't think much of it, parked the car and went into work. Come out of work (it is now 70 and sunny) jump in the car and get back on the highway. I look down and notice the AC button is off, and it will not stay on, so no cold air blowing from the vents. I get home check the codes with vagcom (please see below), and find a couple of weird faults that all seemed to happen around the same time. I cleared them and will see if they come back, but i'm curious if anyone had any insight or advice. I am still covered under Audi CPO warranty, should i get it looked at?

Edit: The AC did come back on once i got back into my driveway. I turned the car off and back on, that did not solve the issue. Turned the car back off, hooked up vagcom, scanned, turned car off. Turned car back on, and AC was back to normal, even before i cleared the codes.


Thursday,26,April,2018,16:47:12:62909
VCDS Version: Release 18.2.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 08: Auto HVAC Labels: Redir Fail!
Control Module Part Number: 8K1 820 043 T HW: 8K1 820 043 T
Component and/or Version: KLIMA 3 ZONEN H04 0121
Software Coding: 6600228000
Work Shop Code: WSC 06325 000 00000
VCID: 392C2477A956C91F756-806C
2 Faults Found:

01592 - Air Quality Sensor (G238)
004 - No Signal/Communication - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 6
Fault Frequency: 1
Reset counter: 229
Mileage: 124652 km
Time Indication: 0
Date: 2018.04.24
Time: 06:55:47

Freeze Frame:
Temperature: 7.0°C

00256 - A/C Pressure/Temperature Sensor (G395)
002 - Lower Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 235
Mileage: 124721 km
Time Indication: 0
Date: 2018.04.25
Time: 07:04:32

Freeze Frame:
Temperature: 15.0°C
Temperature: 73.0°C
Load: 0.0 %
Absolute Pres.: 0.6 bar
RPM: 1200 /min
Speed: 0.0 km/h
Current: 0.000 A
Temperature: 27.0°C




Thursday,26,April,2018,16:47:48:62909
VCDS Version: Release 18.2.0 (x64) Running on Windows 10 x64
www.Ross-Tech.com

Address 09: Cent. Elect. Labels: 8K0-907-063.clb
Control Module Part Number: 8K0 907 063 DH HW: 8K0 907 063 DH
Component and/or Version: BCM1 1.0 H16 0103
Software Coding: 26000091803CAFE0210040C300003D0D0F9CD308A209022100 0008004000030100000030000000
Work Shop Code: WSC 06325 000 00000
VCID: 78AAE173D2DC10174A8-802C
1 Fault Found:

03020 - Local databus 2
012 - Electrical Fault in Circuit - Intermittent
Freeze Frame:
Fault Status: 00101100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 229
Mileage: 124652 km
Time Indication: 0
Date: 2018.04.24
Time: 06:54:46

[drmonkey]

002 - Lower Limit Exceeded - Intermittent

That coupled with the fact that the A/C button wouldn't stay on and a/c not working. I would look at the HVAC Pressure Switch (near the front of the condensor)...might be faulty and not actuating properly which will cause the compressor to read higher or lower pressure in the lines. It's fairly cheap and can be changed without evacuating the system.

[bberg22]

That coupled with the fact that the A/C button wouldn't stay on and a/c not working. I would look at the HVAC Pressure Switch (near the front of the condensor)...might be faulty and not actuating properly which will cause the compressor to read higher or lower pressure in the lines. It's fairly cheap and can be changed without evacuating the system.

Awesome, thank you. It happened again this morning so it definitely needs to get looked at.

[steampunkjunker]

I had this issue too and had the dealer do it because I thought it was going to be a big deal...so a $50 part ended up costing me $300 installed. If you can just try to replace that sensor yourself.


Sent from my iPad using Audizine

[bberg22]

Yea I am going to replace the sensor myself. I think now its a $90 part but if it works, still better than paying the dealer.

[bberg22]

Update:

I got a new g395 sensor from Audi but when I went to take the old one off, the schrader valve did not close so the "freon" was leaking out. So i quickly reconnected the old sensor and tightened it down. I then checked the AC and it was now working. Is it possible the schrader valve was stuck closed causing the low pressure reading?

Will monitor for a few days and see how it behaves. Maybe this can save someone some money in the future...

Anyone know if Audi will give me a hard time if i try to return the unused part? I didn't even open it.

[drmonkey]

The schrader valve is also a common failure point of our a/c systems, it should close whenever your remove the pressure switch so I would bet that it's the faulty part. Unfortunately, you have to evacuate the system to replace it.