AC not turning on. results from scan9495 within

**BLK95TA** · 02-10-2014, 08:13 PM

So i realize it's February and half the country is freezing their ass off, but here in FL, it's AC weather. I had my AC system redone about 2.5 years ago, and of course the warranty was 2 years IIRC.

today i tried to use the AC and it won't kick on. i think it was working a few weeks ago. I tried changing some of the relays around but that didn't work, i also ran scan9495 on the car and am getting 82PSI for a reading with the AC on. It doesn't sound like my fans are kicking on when i turn on the AC so i think either the AC not coming on is keeping the fans off, or the fans not coming on is keeping the AC off?

i did not ever see the green communication light come on during scan9495 for the AC clutch. the AC green light would go on and off when i switched the AC on and off.

**firebird_1995** · 02-10-2014, 08:47 PM

Did you check the fuse?

***Fastbird*** · 02-10-2014, 08:53 PM

Is that 82 PSI reading the high or low side reading? Odds are it's the high side and that's too low for the PCM to kick the compressor on. Probably needs a charge due to a leak somewhere if that's the case.

**BLK95TA** · 02-10-2014, 09:15 PM

well i forgot to read DTCs and it was right in front of my nose "code 61 AC system fault test" i cleared the codes and the AC kicked back on. it's not super ice cold, but was showing around 100psi on and 74F was the coldest AC temp reading i got. i hear a bit of squeaking but i think it's a pulley or belt as it didn't seem to matter whether the AC was on or off. Similar thing happeend to me in 04 where i lost AC and spent $60 at a shop only to have them clear the codes. here's a reading from scan9495 after i got the AC working. sorry it's a bit blurry.

1653453_713387622027184_481466568_n.jpg

**firebird_1995** · 02-10-2014, 09:21 PM

There is only one sensor on the a/c circuit and it is on the high side, however, it only needs 25 psi to allow the clutch to engage. What is the ambient air temp right now?

**BLK95TA** · 02-10-2014, 09:27 PM

when i noticed the AC wasn't working earlier today? 82

current air temp is 65

the AC is definitely working now. i can feel a drop in termperature from vent on cool, to AC. and the comp kicks on. i took it for a drive and it seemed to cool more as i drove (noticed the temp reading went down from 90 to 74) but doesn't kick out much cool air at stop lights which i think is pretty normal. maybe it needs a charge, but i at least got it working. i'd assume if it was low enough to pose a threat to the AC system, the car would have immediately shut the AC down again when i tried to turn it on after clearing the DTC. i probably had it on in the garage for 5-10 minutes, then drove around the block, shut the car down, restarted and let it run for another few minutes and the AC stayed on the whole time.

**firebird_1995** · 02-10-2014, 09:37 PM

If its 65° outside and its not too different in car, you're only getting 75° from the vents and the pressure is 100 psi id say the system went flat or close to. Look around the compressor and all connections for oil. If the system didn't suck in any air from the leak you may get lucky and be able to tighten what's leaking and recharge. Otherwise its going to need to be evacuated and recharged

**firebird_1995** · 02-10-2014, 09:39 PM

@65° ambient temp you should have ~40° air coming from the vents

**BLK95TA** · 02-11-2014, 12:26 PM

tested AC again today. AC seems to be working pretty good. was reading a little low on the gauge when it was 70 degrees this morning but now at 80 degrees it's reading right around 25psi right at the low end of the green on my gauge. maybe it needs topped off a bit but it is working. the car hasn't tripped the 61 code and shut off the aC again.

that 80-100psi i read on the computer must have been the high pressure side? i'm using one of those recharge kit gauges for the low side.

if there was a bad leak in the AC system, wouldn't turning the AC back on immediately shut it back off as soon as it hit X pressure? i did not add any R134 to the AC system. i only measured it with a gauge not even hooked to a refrigerant bottle.

**firebird_1995** · 02-11-2014, 02:17 PM

Refrigerant pressures will always be lower when the ambient temps are lower. The pressure transducer is on the high side. The idea is, when the system is off the lines will equalize. If the pressure is below 25 psi (at any time) the pcm will command the ac clutch off. Last night your high side pressure was about 15# lower than what it should be based off of 65° ambient temperature +/- 5# depending on humidity. The temp of the air coming out of the vents is a better indicator of performance rather that the auto store gauges in my opinion. Do you have a way to measure air temp?