AC not cooling now

Joshawa

Joshawa

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Idk if my LS is a pile of crap because everything likes to break on it...

2nd Gen 03 LS V8 Sport. How would I go about using ForScan to find out what errors the system has? Would it just be listed with the modules?

I don't hear the Rad fan spinning up when I turn on the AC like I usually do, It blows hotter air if i turn up the heat, but it doesnt cool down.

I'm pretty sure I owe Joe like $250 by now for all the advice he's given me lol. any help would be appreciated, before the next thing breaks too...

RIP Rigs
 
Forscan will probably not diagnose your no AC problem, but it wouldn't hurt to see what it has to say.

Step one for you: Locate your AC compressor clutch. It is belt driven at the front left (driver's side) of the engine, down low. When the AC is off, the outer part (pulley) of the clutch spins with the engine running, but the inner part does not turn. With the AC on, the inner part spins at the same speed as the outer part. With the engine running and the AC on, is the inner part of the clutch spinning?
 
I'll check joe. You got a paypal? or a wishlist on amazon haha
 
That's a good question, let me test after I eat dinner and then plug in FORScan and see if it tells me anything. I'm probably gonna make just a boatload of FORScan tutorials one weekend and try and get it to be a pinned post
 
These are the errors I got on Forscan. Maybe this will shed some light. I will be able to check compressor tomorrow. Rattling is still there, sounds like its coming from somewhere else.

b1242.PNG


b1947.PNG
 
Well, looks like I was wrong and it possibly did diagnose your problem.

For the recirc error, do a little searching. There is a good thread on here about it. A plastic part breaks, and it may have broken because of an issue with the DATC itself. It's only a pain to fix because of the trouble getting to it, and junkyard parts are probably the only source for replacements. The good news is that this is not your no-cooling problem. If you do nothing at all to fix it, you may never even notice that it isn't working correctly.

The evap sensor error: This can and will cause no-cooling. It's a $20 part and it's actually easy to get to and replace. Even better, you can verify it by unplugging it. If you unplug it and the AC starts working again, it's the problem. If you look up under the dash on the driver's side, there is a big black air box at the center of the dash that runs from the floor to the top of the dash. On the side of that, there are two white sensors with two-wire connectors plugged in. One is very low, just about at the floor. The other is about mid-way up. That's the one you want. Just twist and pull to remove the sensor. The part number is XW4Z-19C734-BA.
 
Last edited:
joegr said:
Well, looks like I was wrong and it possibly did diagnose your problem.

For the recirc error, do a little searching. There is a good thread on here about it. A plastic part breaks, and it may have broken because of an issue with the DATC itself. It's only a pain to fix because of the trouble getting to it, and junkyard parts are probably the only source for replacements. The good news is that this is not your no-cooling problem. If you do nothing at all to fix it, you may never even notice that it isn't working correctly.

The evap sensor error: This can and will cause no-cooling. It's a $20 part and it's actually easy to get to and replace. Even better, you can verify it by unplugging it. If you unplug it and the AC starts working again, it's the problem. If you look up under the dash on the driver's side, there is a big black air box at the center of the dash that runs from the floor to the top of the dash. On the side of that, there are two white sensors with two-wire connectors plugged in. One is very low, just about at the floor. The other is about mid-way up. That's the one you want. Just twist and pull to remove the sensor. The part number is XW4Z-19C734-BA.
Click to expand...


FORScan is a frigging godsend, I'll test the sensor when I go on my lunch at work. And I'll probably dedicate this weekend to making a post about everything you can do with it!
 
Joe I'm having a difficult time locating it, maybe it's right in front of me and I just don't see it, here's up under the dash, where would it be?

20170829_090631.jpg
 
Also could a clogged Cabin Air filter cause issues? I'm reading on the Jag forums someone said that if it gets clogged there can be weird sensor problems.
 
If you have airflow from the vents, the filter is not the problem. (Still, if it's not white, replace it.)
I actually had to replace the sensor on my 04, but I'll have to look at one of mine to be sure. I think that it is the white rectangular thing (at an angle) at the upper right of your picture, on the black box. I actually have one (a defective one) still sitting on my desk right now. I'd take a picture, but I think that the part of it that you can't see till you remove it might confuse you.
 
I found it and unplugged it but no AC still. Damn. My rad fan still doesn't spin up when I turn on ac though.
 
Joshawa said:
I found it and unplugged it but no AC still. Damn. My rad fan still doesn't spin up when I turn on ac though.
Click to expand...

Scan and see if you are still getting the shorted error (also need to see if the clutch is engaged or not). If you still are, then it's the wiring to the sensor, or probably more likely the DATC itself.
 
What's the best way you'd suggest to see if the compressor is spinning?
 
Yes, below is better, but you can just barely see it from above, maybe.
 
the only code change from unplugging the sensor was the datc just saying it was a total failure now instead of a short to ground. I still have to check the clutch.
 
Ok so I verified that the compressor inside is spinning. My neighbor who's a mechanic that works on reefer units is bringing home the gauges tomorrow to test the pressures and I also recorded live data regarding the AC from FORScan ( I'll upload later). I replaced the sensor today and the error codes disappeared but the lack of cool air persisted. Can the compressor be jacked up internally? Would a bad DCCV cause this?
 
Possible, but rare. Often they first get to not cooling at idle, but still cooling at higher RPM.
The more painful possibility is the expansion valve. This too is rare.
The DCCV is a common problem, but this does not match with the common symptoms.
 
If it affects the option of a dccv at all, I still get cool air at highway speeds ( it's the speed not the rpm, verified by driving at 2500 rpm at low speed using sst). Not cold, but about a refreshing as you'd expect having the windows cracked. Once I slow down, it's back to hot air
 
I just went out to check, the Engine fan wasn't spinning when I had the AC on, however I did a KOER test earlier and it spun the fan to max. I also do hear the engine fan rev up when I turn it on after the car is already warmed up. Here are the screen shots from any data that ForSCAN could collect, as well as what they mean (I'm sure you know already but just in case and/or for other readers :) ).

Capture1.PNG


Capture2.PNG


I was told by my neighbor that the sensor should be getting 5 volts and the pressure should be near 300 psi. this equates to roughly 110 psi (kPa to PsI conversion). I thought that this was weird because that means both the pressure and voltage of that sensor are down to about 1/3 of normal operation.

He could be wrong based on he's never worked on an LS before, but it's just an observation until Joe confirms/denies. Of course, we aren't taking the computers word for it and we're testing the pressures with gauges tomorrow.
 
300 if it is close to 100 degrees there, otherwise somewhere in the 200s. 5v doesn't sound right, but I'm not positive on that. Pretty sure it has to be over 110 to turn the fan up.
 
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