A/C Question
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,313
Likes: 512
From: Carmel CA
A/C Question
I have a problem in the A/C system on my 93. The system keeps giving me a fault code of 09 for low refrigerant. I have checked everything and the system has the correct amount of R134. I reset the A/C system and the engine ECU. It works for a few miles and fails again. I replaced the low pressure sensor and that did not fix the problem. Has anyone else had a similar problem and does anyone have a suggestion as to what my problem might be?
Thanks,
Doc
Thanks,
Doc
Le Mans Master
Joined: Aug 2005
Posts: 7,392
Likes: 218
From: Merritt Island, FL
The only way to check the amount of refrigerant present, is to evacuate it, and then weigh the recovered refrigerant. Hooking up gauges to the system is NOT an accurate way of assessing the state of charge.
I suspect you have a leak somewhere.
I suspect you have a leak somewhere.
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,313
Likes: 512
From: Carmel CA
I did scan the system and everything looked good. I charged it with freon and that did not help. If I clear the code by disconnecting the battery, the system works fine for a while, then the same problem comes back. I am tearing my last few hairs out.
Doc
Doc
Burning Brakes
Joined: Aug 2010
Posts: 951
Likes: 3
From: Placerville CA
When the code comes up, am I supposed to evacuate the system, and weigh the freon? I was not aware that I needed to do that.
My '94 Corvette FSM, FWIW, has a diagnostic for "insufficient cooling" (but maybe that's a separate issue from a fault code) that says the compressor should cycle on at 41-51 psi and off at 20-28 psi.
Or maybe I don't understand this problem.
Le Mans Master
Joined: Aug 2005
Posts: 7,392
Likes: 218
From: Merritt Island, FL
I'm curious, too. On my other cars the right amount of refrigerant is determined by pressure in the system. I have just added the amount necessary to get the pump to kick on while the engine is running and the a/c switch ON. Is the Corvette somehow different?
My '94 Corvette FSM, FWIW, has a diagnostic for "insufficient cooling" (but maybe that's a separate issue from a fault code) that says the compressor should cycle on at 41-51 psi and off at 20-28 psi.
Or maybe I don't understand this problem.
My '94 Corvette FSM, FWIW, has a diagnostic for "insufficient cooling" (but maybe that's a separate issue from a fault code) that says the compressor should cycle on at 41-51 psi and off at 20-28 psi.
Or maybe I don't understand this problem.
Pressure does not indicate how much refrigerant is present in the system. Yes, by adding enough to allow the system to function, you can be somewhat close, but less than the correct charge, may result in insufficient carriage of refrigerant oil to the compressor, shortening its lifespan.
Lots of people service their AC the shadetree mechanic way. Doesn't make it the right way.
Burning Brakes
Joined: Aug 2010
Posts: 951
Likes: 3
From: Placerville CA
Lots of people service their AC the shadetree mechanic way. Doesn't make it the right way.
Four cool, happy years and counting since I recharged my Maxima and a little longer than that for my daughter's Accord. Guess I'll have to stay in the shade.
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Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,313
Likes: 512
From: Carmel CA
When I checked my system, I used a gauge set-up. I am sure that removing the freon and weighing it is the proper method when you are concerned about the oil content. In my case, I am having a problem with the system sensing low pressure. I don't know if the sensor has some way of detecting oil, but I don't think that it does.
Doc
Doc
