2004 XC70 A/C Quits Cooling

Local Boy · Post by **Local Boy** » 01 Jun 2015, 10:25

AC will occasionally (once or twice per week) not cool if the car was turned off with AC running. Pulling fuse for ECM resets the problem. The AC doesn't fail while car is running, or when AC was turned off prior to turning the car off. Any ideas?

Post by **abscate** » 03 Jun 2015, 04:39

That's an odd one. It does sound like the control unit needs rebooting. There isn't much you can do without software on P2s, though.

Post by **regent** » 03 Jun 2015, 08:25

If you have (access to) a VIDA/DiCE setup, you want to look for CCM-related or other modules' COMM Fault codes that may cause the CCM to get kicked out of line.
Also, look for ripple in your supply voltage to the CCM (with the engine running), the problem could be simply noise (EMI), I am thinking a bad main filter cap, or the alt, or simply a broken/loose ground somewhere...

Local Boy · Post by **Local Boy** » 04 Jun 2015, 07:00

Thanks for the responses!

I was thinking of a pressure or temperature issue (or bad sensor) that occurs when the car is turned off and the AC system is in operating mode??

Post by **regent** » 04 Jun 2015, 07:10

That could be, too.
But I strongly recommend reading the car for codes as a less costly approach before your start throwing parts at her (unless you have an 'inventory' car in your garage to borrow parts from...

Post by **oragex** » 04 Jun 2015, 07:12

Just to make sure, the gap at the A/C clutch is withing the specs?