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Ju1ce

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Discussion starter · #1 ·
Hey SwedeSpeed,

Just a quick write-up of a recent repair I thought the DIY community would be interested in....especially with the record breaking heat we are dealing with!

Observe all appropriate safety precautions when lifting a vehicle, working around a running engine and/or walking down stairs. I accept no liability for your actions.

Symptom: Intermittent A/C compressor operation

Fault: Weak compressor clutch/ Excessive Air gap

Test: Engine running, A/C "on" but compressor is not engaged. With a small piece of wood (hammer handle, stick, etc) give the face of the clutch a quick tap between the 6 and 7 o'clock position. If the fault is a weak clutch (what this write-up will address) the compressor will immediately engage and may knock your tool out of your hand or possibly into your hand (the 6-7 o'clock recommendation will reduce the chance of being knocked into your hand).

From what I can observe the air gap on these compressors are set by three small rubber bumpers. I slipped a suitable sized e-clip http://bfy.tw/Iw5u between the large part of the rubber bumper and the metal of the clutch. It is a little bit of a fight to get both ears of the clip started between the rubber and face of the clutch, I found a screwdriver to pry the air gap shut opened up the slot better, pair of needle nose pliers to insert the clip to start and then regular pliers to squeeze it home worked the best. With a little practice the last one will go in surprisingly easy. Still with the engine off rotate the face of the clutch to make sure it still moves freely and no dragging.

I estimate this closed my air gap by ~.010 and after the installing the three clips my compressor engaged 10 out of 10 tries! :cool:

Good luck, hope this works for some more people! Happy motoring!

Mods: This repair will work on any compressor that uses these rubber bumpers, I am confident they are used on many (if not all) other models. It may be helpful to sticky this somewhere it will get better visibility. If pics are necessary to get the point across I can take some/ upload after I get back from my trip.
 
Thanks for sharing this fix, which I thought I needed. Upon experiencing a gradual reduction in cabin cooling after an hour or so, I checked my compressor clutch air gap and found it to be just shy of .3mm - so that does not seem to be the problem. Then I hooked up my VDash for the first time since adding a tune. It gave an impressive list of DTC's, all the more amazing since everything on the car works! There were faults relating to power steering, wheel sensors, etc etc, but that's a topic or three for another day. Here are the CCM DTC's displayed, both before and after refresh:

Red X - CCM-0009 Blower fan motor passenger compartment temperature sensor. Blocked.
Yellow X - CCM-DD33 Damper motor defroster. No communication.
" CCM-DD32 Right temperature damper motor. No communication.
" CCM-DD15 Left temperature [ditto above].
" CCM-DD16 Damper motor air distribution. No communication.
" CCM-DD31 Recirculation damper motor. No communication.

Back last winter we had a similar problem with heating effect going away after an hour or so. I checked the sensor that sits under a cover behind the waterfall and cleaned it, with little apparent change. We dealt with that problem by simply turning the temperature control to "Hi". By the same logic, turning cooling control to "Lo" should solve the current problem.

Above is pretty much the sum total of my knowledge of Volvo climate control. If there are tutorials or stickies I should read, please link them.

And if this post constitutes a thread hijack, I apologize and will start a new thread. tia,

686Sport
 
Discussion starter · #3 ·
Hey 686sport,

Not sure if your dealing with the same problem or not. General rule thumb with so many DTCs is: write them down, clear and drive it for while then re-scan, fix the ones that return first.

If you want to check if it is air gap related, drive it around until it's not cooling well and check to see if the compressor is engaged. If not, give it a whack. If it engages and continues to cool for a while try the shimming I described.

I first noticed that my cooling was hit or miss when I started the car and after 30 min of driving it would drop out and not come back, assume it was cycling to keep from freezing up and not re-engaging
 
Already many threads about fixing an intermittent AC with the best one already stickied (but thank you for contributing to the forum! DIYers like you make this community great and it's valuable to have your shared knowledge). https://forums.swedespeed.com/showthread.php?141183

What you have done is known as the "bread clip fix," which can be done with E clips or plastic bread bag clips, but I do not advise it. While it will work for a few days or even a few years, the clips put added pressure at their points of contact and your clutch is not making a perfectly even contact with the compressor. You also run the risk of the clips eventually popping out, causing very uneven wear and eventually trashing the clutch long before it's useful life is over.

The proper fix is to remove the clutch and then remove/replace the washer shims on the center bolt to get your clutch gap back within spec. It's a pretty easy 20-30 minute job once you know what you're doing. A clutch puller tool will make the job much easier, but you can also carefully pry the clutch off (once the center bolt is removed) using multiple flat head screwdrivers and evenly prying from multiple sides at once.

Make sure you still have sufficient gap between your clutch and the compressor so that it can easily disengage when it gets warmed. Otherwise you will also risk the clutch getting stuck engaged and burning itself out.


https://blog.fcpeuro.com/how-to-fix-intermittent-ac-in-a-volvo-p1
 
Following advice from this thread, I printed DTC's and deleted. After a short drive, I rechecked and then refreshed DTC's. Now there are only 3:

CEM-3AOO ECM software. Faulty signal.
ECM-740C Communication central electronic module (CEM). Signal too high.
CCM-0009 Blower fan motor passenger compartment temperature sensor. Blocked.

Of course I'm curious about the first two, but suspect that only the third obtains in this case. Does this just mean I need to remove and clean the temp sensor that sits behind the plastic cover in front of the waterfall? As described at

https://www.justanswer.com/volvo/7jaj8-recent-service-visit-dealer-diagnosed-problem.html

tia, 686Sport
 
I'd start by putting a vacuum nozzle up to the little 3-bar grille and pulling out the dust kitties. The sensor is just a little glass-bead thing that sits right behind the grille. The fan pulls air past it. Don't give it too big a vacuum shot, that fan will really spin!

Those CEM and ECM codes are pretty serious, but likely not related to your a/c issue. Basically they are saying the CEM and ECM can't talk to one another at least in some communication channels. Have you had any major service, and/or have you checked for coolant leaks above the CEM (behind glove box)?
 
Is it necessary to remove the waterfall before vacuumimg?
Look just below the ignition switch, near your right knee, you'll see the grille.
 
Just for s**ts and giggles I removed the waterfall and then got a good look straight in to the fan and thermistor. No action from the fan before or after using a battery-powered "detail" vacuum.

Subsequent codes included lots of ccm and infotainment stuff, all of which went away upon reset. All that remained were the blocked fan fault and ECM-740C. Tuner says that just shows that there is non-OEM software in the system.

So I assume that silent fan and continuing blocked fan message can only be remedied by replacing CCM. Can this be done without additional software reset?

tia, 686Sport
 
I'm not sure why you removed the waterfall - that's the actual console vertical piece, and the CCM is a control module with all the buttons on it.

The piece you want is in the dash itself, attached to the panel which covers the steering and pedal guts above the driver's legs. I just happened to be into mine today to replace the cabin air filter, so I snapped some pics for you. Mines a 2005, you may have some differences in your 2008.

Here's the fan (and the hole it clips into), just a little dust in mine but I cleaned it out not too long ago.



And here's the back side of the unit, with a part number 3524841 visible (it ain't cheap!)
 
Aha! Thank you, sir. I removed the waterfall because various online sources [not SS] indicated that the fan was in the vicinity of the cabin heat control knob. I had done this just before your post which clarified the location. Another post also stated that the fan was integral with the CCM, so that replacing the fan required installing a new [or at least different] CCM. Now I see that the fan and thermistor unit is available by itself - a bargain at only $169.42 at FCP.
So as soon as I can stoke up the desire, I can get rid of the code and fix my CC issue. Now I kinda wish it had been the clutch slipping instead...

686Sport
Former: 1963 PV544 [B18], 1964 122S [a dog], 1970 145S [Wonder Wagon w/cam, 123GT intake, full iPd chassis], 2004 V70 awd 2.5T [bigger brakes, 16T w/ARD tune]
Current: 2008 V50 T5 awd [ARD Stage II, 3" dp/cat, Typhoon oep, do88 i/c, soon to have 320's]
 
Discussion starter · #16 ·
Didn't realize there were already repair instructions available, feel free to lock/ delete/ or otherwise.

Already many threads about fixing an intermittent AC with the best one already stickied (but thank you for contributing to the forum! DIYers like you make this community great and it's valuable to have your shared knowledge). https://forums.swedespeed.com/showthread.php?141183

your clutch is not making a perfectly even contact with the compressor.

https://blog.fcpeuro.com/how-to-fix-intermittent-ac-in-a-volvo-p1
Wrong.

When the clutch is engaged the pressure is set by the electromagnetic force which pulls the clutch face clear of the rubber bumpers and shims, only when the clutch is disengaged are the news shims holding the air gap closer than tighter than it had been before.
 
HELP!!

Hey guys! Long time no see!

Anyone know whether they sell just the A/C Clutch and shims themselves? AKA not the whole compressor?

Just had to take out the last shim from my compressor clutch and I'm sure it's near the end of it's life but I'd rather spend a little money now and replace the compressor once it actually goes out... living on a budget... meh...
 
From what I've seen a replacement clutch is the same price as a new aftermarket compressor.
 
Just so you know, its also easy to do this fix using cable ties. Was doing some research on this very same issue (last year my AC stopped working) and that was one of the DYI remedies. Still work ever since, fingers crossed.
 
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