# AC stuck in "economy" mode



## VW KEVIN G (Oct 26, 2000)

My air conditioning is stuck in economy mode on the control panel so my air conditioning won't turn on. There are no leaks in the system and all of the components like the compressor, condenser, and dryer were replaced last summer by VW. I took it back to them and they said their computer wouldn't fully talk with the Audi so they could only diagnose it so far.
Does anyone have experience with this problem? The VW dealer suggested it may be in the dash control unit.
My oil level light is stuck on due to broken wire(s) under he car, does this warning effect ac operation?


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## neu318 (Feb 18, 2003)

Having had AC issues recently, it's either you have no pressure/freeon in the system or the control valve on the compressor is bad. I call bull**** on the can't communicate with the system if you took it to the dealer. Might want to take it to an A/C technician to have them check it out.


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## Kevin A3 Quattro (Sep 10, 2014)

just had an AC hole in my 3.2 fixed and the system vacuumed. My light was staying on and obvi just blowing hot air. It does not seem like either of those issues would pertain to you being as how you just had your AC worked on.


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## Tcardio (Mar 19, 2009)

another example of why everyone who owns an audi and has paid a small fortune should own a VCDS cable for 300 bucks extra. I would pull the unit and unplug it and reconnect and see. run a scan


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## VW KEVIN G (Oct 26, 2000)

Tcardio said:


> another example of why everyone who owns an audi and has paid a small fortune should own a VCDS cable for 300 bucks extra. I would pull the unit and unplug it and reconnect and see. run a scan


Thanks for the info. I'll try that. I really do need to buy a VAG Com. The dealer has a VAG Com though so I don't know if it would have helped this time.


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## GvFx (Feb 16, 2015)

Had the same problem, was driving and out of nowhere it came on... Engine cooled down, and the problem went away. Haven't gotten it since.


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## Audi_Mechanic (Mar 24, 2012)

VW techs typically aren't as 'strong' as Audi techs are when it comes to diagnosis. But VW tech's don't have access to Audi specific information and we don't have access to VW specific information. I've been able to convince the audi dealer scan tool (ODIS software) that my R32 was an A3 3.2 so I don't see why the VW tech couldn't get your A3 to be scanned as a GTI/R32; maybe VW's version of ODIS isn't as elaborate. On the other hand, sometimes I have to grab a bentley scan tool with the older VAS-PC software just so I can diagnose old Audi's from the late 2000's and earlier (yeah that doesn't sound right). Current dealer scan tool software is sh!t for most non-current generation Audi's. Audi likes to make our lives difficult. So the excuse given by the VW dealer is mostly true. 


Anyways, did you get a copy of the scan that shows whether or not the climate control head stored any DTCs? Broken wires to the oil level sensor probably won't affect a/c operation, unless the breaks are due to rodent damage. In which case, inspect the wires to the refrigerant pressure sensor for breaks/rodent damage. You might have a failed pressure sensor, low refrigerant, failed compressor (being recently replaced doesn't mean much), failure with cooling fans, other wiring issues or something else I can't think of right now. If you obtain a way to scan it yourself, check refrigerant pressure in I think value block 1 of climate control module address 08. It should read somewhere in the range of 4-6 BAR with a/c off at about 70F. If it's much lower/higher than 4-6 bar than the sensor is likely bad. I think value block 1 also shows compressor solenoid current; it should read ~0.650A with a/c on, but that might not be a useful check if econ is stuck on. 

I'm working off memory so these values and block #'s might not be very accurate. I do so many different things each day that it gets hard to remember every little detail.


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## VW KEVIN G (Oct 26, 2000)

I guess the high pressure cutoff switch and air quality sensor are showing faults. Are these not things that would cause the ac not to work? I'm not sure why they would suspect the control unit if these things are showing faults.


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## Audi_Mechanic (Mar 24, 2012)

Give me your VIN and when I have time I'll look through wire diagrams to see if those components share circuits.


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## VW KEVIN G (Oct 26, 2000)

WAUHF78P46A061508

Thanks alot. I really appreciate the help. :beer:


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## Audi_Mechanic (Mar 24, 2012)

Those components share a ground circuit with the fresh air blow control module and the climate control module. So if you still get air blowing through your vents, then their common ground point is likely okay. However, there could be problems after their ground circuits split which is why taking a gander at wiring for external damage worn't hurt.

The high pressure sensor and air quality sensor are right next to each other on the same wire diagram page. The ground circuit continues off onto other pages. But their power supply comes from a 5A fuse SC4, which is on fuse panel C - on left side of dash. Check/replace that fuse to see if it pops again or if a/c comes alive. 

According to Audi's component location list, that fuse also supplies power to: 
ASR/ESP Button -E256- 
Back-Up Light Switch -F4- 
High Pressure Sensor -G65- 
Air Quality Sensor -G238- 
Oil Level Thermal Sensor -G266-

So check those components to see if they're operational. Perhaps the broken oil level sensor wires have caused that fuse to pop, thus disabling your pressure & air quality sensors. Looks like your oil level warning might actually be related.


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## VW KEVIN G (Oct 26, 2000)

Thank you!!


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## VW KEVIN G (Oct 26, 2000)

Thank you Audi_Mechanic!! The 5amp fuse in position 4 for the heating and air conditioning was blown. It probably happened when the wiring harness for the oil level sensor was broken. I now have cold air!:beer:


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## Audi_Mechanic (Mar 24, 2012)

You're welcome. Stay cool Kevin.


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## vwlippy (Jul 17, 2001)

VW KEVIN G said:


> Thank you Audi_Mechanic!! The 5amp fuse in position 4 for the heating and air conditioning was blown. It probably happened when the wiring harness for the oil level sensor was broken. I now have cold air!:beer:


Awesome!


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## azoceanblue (Aug 13, 2006)

VW KEVIN G said:


> Thank you Audi_Mechanic!! The 5amp fuse in position 4 for the heating and air conditioning was blown. It probably happened when the wiring harness for the oil level sensor was broken. I now have cold air!:beer:





vwlippy said:


> Awesome!


Fookin Wow! and what he said :thumbup:

Amazed that the $90 diagnosis would not have included checking the fuses :facepalm:


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## ECS Tuning - Audi (Oct 12, 2009)

Glad to hear it was a cheap fix! Most common issue with the econ light and no cold air I've heard is usually no refrigerant or the high pressure switch is bad. 

This is the first I've heard of the fuse being the cause. But definitely shouldn't be over looked as many times a fuse is the least expensive fix and can easily solve the issue. 

Jason


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## BeeAlk (Jun 3, 2013)

Audi_Mechanic said:


> Those components share a ground circuit with the fresh air blow control module and the climate control module. So if you still get air blowing through your vents, then their common ground point is likely okay. However, there could be problems after their ground circuits split which is why taking a gander at wiring for external damage worn't hurt.
> 
> The high pressure sensor and air quality sensor are right next to each other on the same wire diagram page. The ground circuit continues off onto other pages. But their power supply comes from a 5A fuse SC4, which is on fuse panel C - on left side of dash. Check/replace that fuse to see if it pops again or if a/c comes alive.
> 
> ...


You are a valuable resource to this forum and ^^^ is proof. You should be gilded or something!


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## louiekaps (Aug 12, 2013)

I agree that was exceptional tech support. Much better than the typical forum response "well I had ______ part go bad, so that is without a doubt what broke for you. Buy ______ part."


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## JBX (Jun 25, 2017)

Thanks for this thread. My fuse was burnt, too. Now I have AC but it takes a while from start-up to start cooling. The fans turn on with ECON light off but they are on low speed. If anyone knows how to get them to go to high speed with AC, I'd be grateful.

Thanks again. (Audi-Mechanic, you rock!)

--jb


2006 A3 3.2 S-line


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