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ac help with audi s4


russian rocket

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hey guys im having issues with my ac in my 02 audi s4

it was working fine and all of a sudden stopped blowing cold air.

my dash is reading the correct temp and my compressor kicks on but does not cycle.

i took it to a shop and they said my low side was reading high and my high side was reading low. i tried adding refrigerant but it wouldnt take any.

any idea what it could be?

 

all fuses are good

no leaks

econ mode is off

compressor does kick on

 

the shop thinks its electrical related

 

any help is greatly appreciated.

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My leaning would be towards one of the pressure switches. Does the blower motor come on?

 

yep blower motor blows strong and the condenser fans kick on.

i would think if it was one of the pressure switches wouldnt the compressor not kick on?

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My first step would be to have the system evacuated and recharged. Does the clutch engage?

 

yep the clutch engages.

 

so do you think the refrigerant is bad or that something got clogged up?

because it was working just fine and then just stopped instantly, no gradual change, just went from cold to warm.

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yep the clutch engages.

 

so do you think the refrigerant is bad or that something got clogged up?

because it was working just fine and then just stopped instantly, no gradual change, just went from cold to warm.

 

The high side is throwing me for a bit of a loop. My thoughts are either A) There is a bad valve in the compressor or B) There may be a lot of moisture in the system.

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hey guys im having issues with my ac in my 02 audi s4

it was working fine and all of a sudden stopped blowing cold air.

my dash is reading the correct temp and my compressor kicks on but does not cycle.

i took it to a shop and they said my low side was reading high and my high side was reading low. i tried adding refrigerant but it wouldnt take any.

any idea what it could be?

 

all fuses are good

no leaks

econ mode is off

compressor does kick on

 

the shop thinks its electrical related

 

any help is greatly appreciated.

 

Find a new shop.

Compressor is being commanded on by the PCM (clutch is engaging) - usually this means there is sufficient charge in the system and all the sensors are giving a signal within the specs the PCM expects to see. However, low side high/high side low typically is one of two things:

1) Compressor internal issue (not pumping)

2) Expansion device issue (TXV) - this Audi uses an orifice tube so #2 is very unlikely

 

From what you're describing - the compressor is not pumping (hence no low side low pressure and no high side high pressure) - or, it is pumping, but there is no restriction (the expansion device) to cause the change in pressure (in this case an orifice tube so not likely the problem).

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Find a new shop.

Compressor is being commanded on by the PCM (clutch is engaging) - usually this means there is sufficient charge in the system and all the sensors are giving a signal within the specs the PCM expects to see. However, low side high/high side low typically is one of two things:

1) Compressor internal issue (not pumping)

2) Expansion device issue (TXV) - this Audi uses an orifice tube so #2 is very unlikely

 

From what you're describing - the compressor is not pumping (hence no low side low pressure and no high side high pressure) - or, it is pumping, but there is no restriction (the expansion device) to cause the change in pressure (in this case an orifice tube so not likely the problem).

That's my main thought. Internal valve failure = new compressor.

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