Air Conditioning problem

2006 Audi A3 4 cyl Two Wheel Drive Automatic 96,000 miles

Recently the A/C will stop working and the ECON (Automatically turns off A/C Compressor for Audi) button lights up. I can not de-select it. The only solution is to turn the car off/on and start again.

1. The problem has gotten worse the hotter out it has gotten.

2. As long as the car is in motion it does not happen, but sitting idol at a stoplight etc seems to click it on (Engine gets hot with no air flow?).

3. AC Blows cold air otherwise when working.

4. Initial smell out of the vents is reminiscent of a dirty dish towel.

5. Since initial occurance I have had the water pump/timing belt remove/replace done (suggested at 110K by Audi).

6. Prior to Belt/Pump R2, car also ran hot, plenty of anti freeze/coolant in it, garage found radiator fan's had become disconnected. Connected them and that problem has gone away.

Question: Could a sticky temp sensor in the radiator system be at fault for this? (Curious since they did not replace it once they found the disconnected plugs on radiator fan) Or is it strictly a A/C issue.

Any suggestions will be helpful. I R2'd my O2 Sensors/ Fuel Filter and Coils/Plugs myself at 75K. (Complete write up here) so I am not afraid to get my hands in there.

Potential Trouble Shooting Ideas I have read so far:

1. Rock has come up and chipped a hole in your .. Line/Compressor (Where am I looking to find this?)

2. Also, siezed compressor happens a lot in 2006-2007 A3's here in the US... results in a burned belt... might be another explanation. (Which Belt, once again, pics would be helpfull)

3. Hi, check the small electric fan on the radiator is running with the ac on. If not, the system pressure runs too high and shuts down. The motor brushes wear and the fan packs up. You high pressure switch mounted on the condenser could also have failed. You can replace this without discharging R134a (screwed onto schrader valve) but you will need to remove OS headlamp to remove it
Also check the compressor clutch is engaged. If you have a late car and VAG com, you can check what pressure the system is running. (Will do this today, however I have not spent the $$ on a VAG, and I have no idea what a compressor clutch is, much less where it is and how to see if its engaged.)

4. Problem was, the system was overcharged by quite a bit hence the compressor shutting down to save itself or something like that. (Could this explain why it only happens when I am at a stand still and their is no air flow across the engine? Think its something to do with the fans not cooling the condenser when stationary as when you drive along the flowing air cools the condenser?)

5. Fuse 8 Actuators/sensors (engine compartment), radiator fan, main relay for ignition coil

Not sure what caused it to blow but it seemed to be causing the three problems I have.
1. The condenser radiator fans not working
2. Intake manifold fault which is an actuator/sensor
3. ECON light is not coming on when vehicle is stationary - as the fans are now running. (Will check this as well when I get home)

6. I have replaced the fuse a few times, it seems to be the intake manifold flap jamming which causes the problem. Mines ok at the minute, once the warmer weather is back it may blow more often and I will then have to replace the intake manifolf flap (Ok, where the heck is the Intake Manifold Flap located?)

7. High Pressure Sensor (G65) faulty (Anyone know where this is?)

8. Disconnect the battery for 20 mins, then reconnect, it fixed it for me. (Car has factory chip, so no harm/foul in trying this either I suppose other than cycling the locks/windows etc when I am done correct?)

 

My common sense tells me this:

When I start my car, and the enviromental system is shut off (Fans turned all the way down) and regardless of how hot it is outside, as long as I wait to get on the road and up to speed (30 MPH) and get some air flowing across the engine, I can start up the fans and turn on the A/C and it blows perfectly cold air. It STAYS on.....

However, If I pull up to traffic, or a stop sign or a red light, and I sit still for a minute... Boom, the ECON kicks on, the air starts blowing warm/hot and I am unable to turn ECON off.

However, If I pull up to the same situation, and proactively turn off the ECS by turning the fans down till the display goes dark and shut off A/C, then wait till I start moving again to turn it back on, it works fine.

Also, if it turns on ECON when I am sitting still, I can turn the car off and turn it back on and it works as well (as long as I quickly get the car moving).

1. I have coolant
2. The Compressor works
3. something is getting to hot and turning the A/C off and putting the ECON on permanently.

***** don't mind me, just thinking out loud**********

 

Bump in hope someone has something. Will check back monyanna

 

Bumpage, still have not had a chance to even pop the hood yet, kids change everything.

Regardless, just wanted to nudge it up in case some have not seen it yet.

And AC still works great and is ice cold, as long as I have the entire ECS fans and all turned off when the car comes to a stand still. And only turn it on while in motion (Air flowing over the engine).

If it sits at a light or sign for a min with the AC on or even with AC off but fans blowing, it kicks into ECON and stays there (Even if I push the button really really hard, or turn ECS all the way off and back on). The only remedy is to turn the car off and then back on.

 

Mine had a similar problem. Took it in to dealer for a check up. They added 300 grams of r134a. The system only holds 900 . That was in March. Just took into dealer last week had a complementary a/c checkup coupon. Still blowing cold air sometimes. However it would just stop and blow hot. Turns out the compressor was bad. Replaced under warranty.

 

Don't mean to resurrect a two year old thread, but for posterity - the underlying causes of this is one TWO things:

-Auxilliary electric fan is dead or dying. Run direct power to lower radiator hose thermoswitch, to verify. Fan should come on under direct power. If not, the fan circuit has a short and the car is actually overheating; the engine ECU will cut the A/C off to compensate(priority is to COOL engine ASAP - not driver!). Once it goes into A/C compressor bypass(ECON mode), the only other way to restore A/C function, is to re-start ignition....even if the car has cooled off considerably. Lack of air flow over the radiator is the leading cause for random ECON mode. The car overheats and goes into crisis mode and starts shutting off stuff that's not necessary....like A/C. Eight times out of ten - it's likely to be the auxilliary electric fans. The other causes of fan-related overheating is going to be either the engine fan clutch, or the fan control module/fan relay/fuses.

-A/C High/Low-Pressure switches. Located at the A/C condenser. The switches detect pressure changes and will shut off compressor, if high system pressures, high ambient heat, or low refrigerant is found. However, it's not as common for these switches to go out, as they are both designed to prevent catastrophic damage of the A/C system. Typically, over-charging the system with r134a will send internal pressures skyrocketing during searing summer heat, and force A/C cutoff. The compressor itself has a Schrader blow-off relief valve on the high-pressure side, once a cold pressure test finds excess r134a refrigerant, so a full evacuation and recharge is unnecessary. A few short bursts of the relief valve while under manifold gauges, is all that is needed to restore correct pressures.

 

my AC has been acting funny lately ... hope it's not any of these issues ...

 

Mine has recently done the same thing. I can not turn the ECON off and I only have hot air. I recently went and bought some canned AC Recharge since it literally had none in it and a week later was fully depleted again. Anyone know what this is probably going to be?