P0118 with A/C and heat on

[DurellB]

I am having an issue with my 98 S70 in the winter where when the A/C is on with the heat up, I get the P0118 code when idling for more than a minute and sometimes while driving. I replaced the coolant temp sensor last year but still the same issue. The thermostat seems fine as the heat works well without the A/C on. This becomes a problem when trying to clear foggy windows/humidity and the A/C needs to be on.

Also to note, in the summer when I am running the A/C for awhile, the cold air disappears and the fix is to turn the A/C off for about 30 secs and it works after turning it back on. Can’t help but but 2 and 2 together and say these are related issues. Has anyone had similar issues? A fix?

[Swedespeed96]

Has the a/c ever been recharged ?

[DurellB]

Has the a/c ever been recharged ?

I do no think so. I got the car in ‘16 and haven’t had it done since I’ve owned it.

[05V70RGT]

Take it to a shop and have it serviced. Don't use a generic can o refrigerant. The system should be professionally discharged and recycled, a vacuum pulled for 30 mins and refilled with the proper refrigerant to the proper charge weight along with oil and leak detection die.

[Kunstlerbild]

Re #4... Or just make sure that they use refrigerant with seal conditioner.
If it does run for a while before shutting down then it is not completely drained of refrigerant which can be explained as normal loss from many years without service and dried seals. There is a low pressure switch that shuts the ac off in that case. More likely it is an overpressure due to too high a temp in the system. It is like having an airlock in the radiator. Shutting it down for a while allows the system to cool down and recondense. Either way get the service
with seal conditioner before having a leak check because the seals dry out if they sit for too long and will leak until some conditioner comes their way. Drive it for awhile after the service, and then, maybe have a leak check done if it doesn't perform properly after a while.

[Kunstlerbild]

Sorry to be incomplete. Just an FYI. I had to talk to my customers about this at my shop in Portland. No recirculate! Do not use recirculate!!!... If all else fails, clean the glass till it squeaks. Any micro matter or blue haze from plastic out gassing will seriously get you fully opaque interior glass. As well, yeah I know but maybe you don't; do not turn on recirculate! The last thing you need is to have all the moisture from your person filling the cabin! Why do you think that when you breath on a winter window it immediately frosts up? redundant but do you get it? HUH, HUH?

[DurellB]

I appreciate all the posts, but I have just noticed after experimenting WITHOUT using the A/C with the heat on I have gotten code p0116 while driving which also has to do with the Coolant temp sensor. Again, the temp sensor was replaced but still not the fix.