ECON light wont turn off / AC not working

[Arese]

Hi everyone,

The AC of my 2009 Audi A4 B7 2.0 TFSI S-Line convertible stopped working and the ECON button won't turn off anymore. I actually already did some digging and found out that it could be:

- Blown fuse (I'm going to check this tomorrow can you tell me which fuse number I should check?)
- Low gas level
- Faulty pressure sensor (g65)
- Leak or part of the AC system broken

In order to pinpoint what's causing the system to go to safe mode I need an ODB2 reader in order to read the system's faults (it could be as simple as a low gas level).

I've read on this forum that you can either buy the more expansive official Ross Tech ODB2 cable to do modifications to the car or buy a cheap generic ODB2 cable that only allows you to read faults.

If it turns out it's only a low level on freon I can go to an AC shop and get a refill. If it's a faulty G65 sensor same I can go to a car shop and specificially ask them to replace the sensor which won't cost much as I saw online that it was quiet easy to change.

Basically if I know what's the issue they won't be able to charge me extra for imaginary extra needed repairs.

Would anyone be kind enough to point to the correct cable for my car? If you got an Aliexpress or ebay link that would be really perfect :)

Anyone what kind of ODB2 reader I should buy for my car?

Would this one to the trick? (I don't need to erase codes, just read them)
https://www.ebay.com.au/itm/All-OBD-...EAAOSwKptcZXyZ

Thanks everyone

[EvolutionArmory]

Buy VCDS. It’s the best 200 you’ll ever spend on your car.

You gotta start by making sure it has the correct amount of refrigerant. The pressure switches won’t allow the AC to turn on if the pressure is too low or too high. If you still have issues after a regas, then the fun begins. Then you get to check pressure switches, the orifice tube, leaks from seals, etc.

I HATE AC work.

And this is where VCDS really comes in handy. It has most of the features the factory scan tool has so you can check many sensor reading for the climate control system.

[oVeRdOsE]

B7 are known to leak from the pressure sensor, its a easy fix.

for the reader, if you're planning to use it often, yeah VCDS is a must, or the OBD-Eleven.



what is does :

https://www.youtube.com/watch?v=1Vzz33IDL4E

where it is :

https://www.youtube.com/watch?v=5ueG8k374Aw

[dalmation53]

B7 are known to leak from the pressure sensor, its a easy fix.

for the reader, if you're planning to use it often, yeah VCDS is a must, or the OBD-Eleven.



what is does :

https://www.youtube.com/watch?v=1Vzz33IDL4E

where it is :

https://www.youtube.com/watch?v=5ueG8k374Aw

You beat me to it. Same thing happen to my friends b7 shop could no figure it out and i'm an amateur and i figured it out lol

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[oVeRdOsE]

You beat me to it. Same thing happen to my friends b7 shop could no figure it out and i'm an amateur and i figured it out lol

Sent from my Vivo One Plus using Audizine mobile app

cost me a dryer, condenser few hours and 2 flush/refill because I could find the leak. I made a test leak at a local shop, and he was telling me that the condenser was hit and it was leaking.

I went back to the shop a 2nd time after I figured it out, bring the sensor with me, and telling him that he should know about this common issue since the shop owner own a rs4 b7 lol

at least he did a refill no charge.

iirc the sensor was about 70$ a local Audi dealer, and the flush/refill about 125$.

But a I got a A/C rebuilt kit on rock auto, + leak test labor + sensor + beer + flush/refill : cost me about 600$... ahhh car work.
rockauto rebuilt kit looks way cheaper than OEM, I wish I still have my OEM one on the car...

[Arese]

Buy VCDS. It’s the best 200 you’ll ever spend on your car.

You gotta start by making sure it has the correct amount of refrigerant. The pressure switches won’t allow the AC to turn on if the pressure is too low or too high. If you still have issues after a regas, then the fun begins. Then you get to check pressure switches, the orifice tube, leaks from seals, etc.

I HATE AC work.

And this is where VCDS really comes in handy. It has most of the features the factory scan tool has so you can check many sensor reading for the climate control system.

Thank you very much for your very insightful answer.
So you reckon I should start first with a regas before diving into anything more complexe.
Ok I'll take it this weekend to the AC shop for a refill and we will see how it goes. I may only be low on freon as I remember last month noticing that the air blown wasn't as cold as it should be.

Just a question for my personal knowledge. Let's say the issue was indeed a low level of freon. When you regas and when the pressure sensor detects a correct amount of pressure in the compressor, will the AC work back by itself or do you still need to erase the code?

You beat me to it. Same thing happen to my friends b7 shop could no figure it out and i'm an amateur and i figured it out lol

Sent from my Vivo One Plus using Audizine mobile app

Exactly why I want to be able to diagnostic the car myself and go to the shop with clear instruction what to do because I don't trust them. They won't spent time doing research online to pinpoint what could be the cause of the issue they will just repair whatever come across their mind and hope for the best while charging you of course

B7 are known to leak from the pressure sensor, its a easy fix.

for the reader, if you're planning to use it often, yeah VCDS is a must, or the OBD-Eleven.



what is does :

https://www.youtube.com/watch?v=1Vzz33IDL4E

where it is :

https://www.youtube.com/watch?v=5ueG8k374Aw

Super interesting videos. So the pressure sensor shown in your videos, is that the G65 pressure sensor?So basically when the sensor breaks, the air leaks through the sensor lowering the pressure measured by the sensor which prompts the computer to go in safe mode resulting in the ECON button to stay on. Did I get it right?

With regards VCDS I know it's an awesome tool but I don't plan on using it often that's why its cost is not justified in my case. I just want the cheapest available tool to read codes. I don't do repairs by myself anymore. I just want to be able to read faults code and go to the shop and tell them what I want done.
When I was younger I bought a cheap ODB2 cable on ebay and was able to read codes on my old VW Golf.
I checked the ODB11 and that looks neat but they don't deliver to Australia unfortunately. Though my parents are in France so I might get myself one for later. Do you use it? How does it compare with VCDS? It can read all the faults code including climate system sensors? If yes for that price it's hell of a deal

[EvolutionArmory]

Cheap scan tools usually don’t allow you to access advanced control modules like the climate control system. VCDS allows you to access them all. You’ll have to look around and see if a lesser scan tool will allow you to access that module.

If you get your AC regassed you can have them add leak detection dye that will glow with UV light. If the regas fixes the issue you’ll know it was low and the dye will tell you if you have a leak after driving for a day or 2. All you need is UV light and just trace the AC system and see if you have a glowing leak.

[Arese]

Sounds like a great idea I'll do that.

And yes I see what you mean about cheap ODB2 cable not being able to read climate system sensors. I message an ebay seller and he told me his cable couldn't read the climate system sensors.

Thanks again for all the information, really appreciate it.

[ifloppedtrips]

My Econ light was also on and system not working. Ended up being the compressor that needed to be replaced. Took one of a car at the junkyard for $30 and swapped it pretty easily. Then $80 for evac/recharge.


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[Arese]

My Econ light was also on and system not working. Ended up being the compressor that needed to be replaced. Took one of a car at the junkyard for $30 and swapped it pretty easily. Then $80 for evac/recharge.


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You did really good! Normally it's quiet expensive to get the compressor replaced at the shop no?
Hopefully my compressor is ok but was easy are talking to swap the compressor? Do you have a link to a tutorial or video by any chance?

[Kingzilla17]

Same issue on my end. AC was blowing ice balls last summer and a few days ago I finally cut it on (Temps hit 80s) but its not blowing cold. I took it to a shop and they are telling me its a bad compressor as it wont hold pressure. The ECON light stayed lit after I left the shop. Ran a scan via VCDS and got code 00819- High Pressure sensor (G65) signal too low. Purchased the sensor and hoping this might help. Is there a way to personally check the compressor? This shop I took it too was just a random one I stopped by and the guy just plugged it up for a few minutes before he was pitching me a new compressor for $400 with a year warranty. Seemed a little sketchy. The heater is working perfect, not sure if that tells anything.

[Theiceman]

As you are not reaching minimum pressure for the high pressure sensor i guess he is assuming compressor is bad. Did you try the sensor ?

I imagine if he threw gauges on it he saw the same thing your sensor did. Question would be is the compressor running ?


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[ifloppedtrips]

yes its usually expensive for the compressor but if you just loosen the belt off it and go under the car its just a few bolts and maybe a sensor should take you about 20 min, its right up front. Also I replaced the condenser, high pressure switch and got recharged before getting a new compressor which ended up being the real culprit.