In reply to Slippery :
IIRC it's a constant-run compressor, with a solenoid to control compressor output. I forget if the solenoid is a linear solenoid or if it is duty-cycled. There is a shear drive in the pulley so that if the compressor locks up, the shear breaks so that the pulley can still spin, but there isn't an electromagnetic clutch in the equation.
Compressors that cycle on and off are so industrial, Audi wouldn't stand for something that clicks on and off all the time 
In reply to Pete. (l33t FS) :
Scratch that thought then 😀. This is way to modern compared to what I am used to.
Is there a way to test if the drive has sheared? I assumed the clutch was magnetic and expected it to kick on and off.
Last night we arranged purchase of another TDI, this one being a 2013 Sportwagen Jetta for the wife. Maybe after I get it home this evening I can pay closer attention to how the A/c should be working.
Quick reading shows there's a refrigerant control valve (RCV) that commonly fails on these Sanden compressors. I may just order one and see what happens.
Busy weekend and it was stooopid hot so no progress on the Audi until last night.
My only goal at this point was to just get the transmission bolted in place. Anything other than that would be gravy.
Getting the trans jack with the trans on top is just too high to fit under, so I used a heavy duty tube sitting on top of the engine and fender to ratchet it up high enough. This also was handy getting things to line up just right. I managed to get it stabbed in first go! Massive relief. I spent another 30 minutes or so getting most of the parts bolted back in but still need to do the DSG fluid service. That's when I decided to call it a night, I had to mow the lawn anyway.
So this evening I want to get the axles and stubs bolted back in place. Once those are in I can do the DSG service. The injectors probably should be done before changing the oil so if I manage to get off early there's a possibility the car could be ready to drive this evening.
I have found purely by accident that using a cherry picker to lift a transverse transmission up is the only way to fly. They usually aren't flat enough on the bottom for a trans jack to articulate them up to lining up. If it's hanging, it is super easy to swing it up here or there to line it up.
In reply to Pete. (l33t FS) :
I believe I did that the last time but decided to try this method out since it would give me more space to work from above. With jack stands below it only allows so much movement of the picker legs to roll around. It was my back up method if this one didn't pan out, but since it worked a treat on the Fiat trans a few months ago it seemed worth a shot again.
Got my early day out of work yesterday, and I was heavily motivated to get this thing back on it's wheels.
Stub axles installed first and then the axles.
Replace trans filter.
Fill trans fluid with DSG funnel kit.
Drain engine oil and replace filter.
Replace fuel filter.
Add oil back in.
Quickly add trans drain bolt back in place trying to not make a mess. The funnel feeds directly into the drain, so it can be messy as hell doing this service.
Reinstall battery tray, intake, new air filter.
Decided it's best to just go ahead and replace the injector seals since I was already adding air to the fuel filter system.
Bleed fuel rail for a few minutes.
Crank it to life and yeehaw it's running again!
Wait for DSG to get up to 35c minimum using OBD Eleven to monitor live data, then pull drain plug. Let drain until it comes to slow drip while running. Replace drain plug.
Realize there is a slight leak at the fuel rail on injector 3. Shut car off and re-seat injector line. Leak gone.
Re-install all splash shields and undertray.
Wheels back on.
Lower back to earth and REJOICE!
I decided it was running healthy enough to pick up my youngest from cheer practice. While waiting for her to get out of practice I reset the oil service light and then used the OBD Eleven to reset the DSG service light.
It drove great there and on the way back a check engine light popped up. It still ran amazing so I wasn't too worried. Unfortunately it's the dreaded codes pointing towards a probable DPF failure. Kinda saw this coming but was hoping to put it off for a while.
I also noticed some bubbles from the glow plug seat area from the diesel that had leaked from the rail. I must have done a terrible job tightening them back down when I loosened them a couple weeks ago trying to get this thing to start. So I tightened the three I initially messed with nice and snug. No more bubbles. I went ahead and cleared the CEL codes to see how long before it pops back up. Hoping since I do mainly highway it might hold off a bit longer.
A/c up next!
Drove to and from work yesterday which is about 65 miles round trip. Check engine light showed its face again on the way home. Codes are the same but also got a couple new ones.
P13D300 - Sensor for internal pressure of cylinder 2
Implausible signal
static
priority - 2
frequencyCounter - 1
drivingCycle - 255
km-Mileage - 214847 km
date - 2024-08-21 16:58:57
P13D600 - Sensor for internal pressure of cylinder 3
Implausible signal
static
priority - 2
frequencyCounter - 1
drivingCycle - 255
km-Mileage - 214847 km
date - 2024-08-21 16:58:57
Technically I saw the cylinder 3 one the other night but attributed that to being a loose glow plug and cleared it. I have either messed up the glow plug harness or damaged them when attempting to remove them? Either way the car seems to run fine so I'm not super worried about it. I'll check connections at the harness to make sure I haven't broken or damaged when removing. They are a pain in the ass to remove gently.
I've also got a wobble of some sort around 70 mph. I think it's tire related, so I'll move fronts to the rear and see if it changes anything.
Replaced the compressor valve today and we now have functional AC!!!
Gonna drive this one to work all week. Got a couple delete kits on the way, one for the a3 and the other for a Jetta wagen I got for the wife. Both are throwing codes to replace the DPF. Hers also is getting a timing kit, water pump, full fluid filter maintenance and probably a DSG flywheel. So it's basically gonna be Groundhog Day for the next month or two.
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