Apparent Air Conditioning Failure

[bobkart]

We got our hottest day of the year so far (86F) and I turned on the AC today for the first time this warm season, only to discover that it's not working.

Fans in the cabin are fine, I can also hear/see the radiator fans working. Fuse for the AC relay (10A) tests good. Looked at the relay but don't see how to remove it for testing (plus not sure how I'd test it).

No DTCs related to HVAC.

One oddity is that the plastic cap on the 'high point' wasn't even finger tight. And I see signs of leakage around it (apologies for the blurry picture). I (hesitantly) unscrewed it, observed no pressure release. I don't know enough about AC systems to know if any of that is to be expected.

Starting to think it might have leaked out all the refrigerant (somehow). Would I expect to see DTCs for that situation? Can these systems be recharged like typical AC systems?

I'm reluctant to bring it in to a dealer. They seem to want to find the most expensive solution. Can a regular auto shop service these systems?

Any help appreciated.

 

[Nubo]

AFAIK, the cap is there to keep the valve clean, not to hold in refrigerant. The white discoloration on the pipe is likely from when the fitting was attached by soldering, brazing or however they do it. If there is an actual leak there you probably would notice a lot of oily residue; The refrigerant contains a dose of oil that keeps the compressor lubricated. The refrigerant itself is just a gas when exposed to atmospheric pressure.

The one thing to keep in mind if using a regular shop -- this system takes a specific refrigerant oil that has the necessary insulating properties for an electric compressor. Typical ICE car refrigerant oil will ruin the system.

Other than that, a competent shop should be able to check for leaks and correct the refrigerant levels. If it's a problem with the electric compressor not operating, then I'm not sure how far they'd get into it.

 

[bobkart]

Thanks Nubo. I'll probably reach out to a local shop we have a relationship with.

One other detail: HVAC power usage in LeafSpy shows zero with the AC switched on.

Does anyone know if there should be DTC(s) thrown for low/no refrigerant?

 

[nlspace]

It would probably be a good idea to find the wiring diagram for the AC system in the Service Manual (HAC section) in order to trace thru the connectors and determine which fuses and relays need to be checked/swapped out.

It seems that the system is not getting the start command to the compressor. Even if there were some leakage there would still be some "freon" in the lines and the compressor would try to start if commanded, and you would see that power draw on the energy screen--that you didn't is a good indicator of no command.

There is a big-ass fuse in the HV junction box for the feed to the compressor, but before tearing into that i would want to check and verify the low voltage 12V supply and control circuits first.

In the 2012 HAC FSM, there are no DTCs for the pressure sensor. There is P3117 in the VCM related to a change of insulation resistance in the compressor motor (due to the customer adding non-approved freon to the system).

 

[bobkart]

Thanks nlspace. Seems like the AC relay is high on the suspect list. I suppose swapping that out is an easy enough experiment to try.

But I think I hear a spinning/whining sound that suggests the compressor is turning, but with no resistance. It's different from the sound the fans make, and winds down more slowly after turning the AC off. As to why that load doesn't register on LeafSpy, it might be small enough to not be counted (due to no resistance). I might try to hear it better by disabling the radiator fans somehow (unplug their connectors?).

It had been a long time since last running the AC, although I ran defrost from time to time over the winter (and it seemed to work). Still, it's probably been at least three months . . . I could see a 'new' leak (crack in pipe?) losing pretty much all of the refrigerant.

 

[bobkart]

Seems like whatever that whine I hear alongside the radiator fans when I turn on the AC is not the compressor. I can touch the compressor body and I don't feel any movement/vibration.

Trying to figure out how to remove the AC relay next.

 

[jjeff]

I would hope any competent shop should be able to troubleshoot low refrigerant or a bad relay and if the refrigerant or oil is special they should be able to source it. While not a Leaf and not even an electric compressor I did have the A/C fail on my works Nissan NV-200 van, on the hottest day of the year! 99 degrees outside and 120 in the vehicle :x
Like you I checked the 2 fuses I could find marked for the A/C and both were good. I noticed that while the outside pully of the compressor spun around all the time the inside didn't, telling me the clutch wasn't engaging. I also felt no loading of the engine when I turned the A/C on, something I always felt before. When I asked around I was told there could be various things that would stop the clutch from engaging, low refrigerant pressure being one of them.
Long story short I ended up taking it in to the dealer for service and low and behold they came up with an estimate saying the compressor was bad, $1600 as it was a work van and the coming weeks were predicted to be in the mid to upper 90s(record hot for early June in my state) I went ahead and got it fixed. Kinda crazy fixing the A/C on a vehicle could cost hundreds if not a thousand dollars more than some used cars seem to go for, but I guess they've got you over a barrel, what else are you gonna do.
I do know when the A/C went out on my mothers Ford 8? years ago she took it to the dealer and they wanted $1300 for an OEM compressor and $1000 for a aftermarket compressor, she took it to a respected local shop who charged her $750 for an aftermarket compressor. When I researched it online it sounded like the compressor had reeds? that would fail making the compressor unusable. Apparently, one could purchase the parts and try repairing it and sometimes it would work but depending how it failed, sometimes it didn't work or there could be other issues with the compressor, which is why she went with the replacement compressor. She drove the vehicle about a year more and probably only used the A/C a half a dozen times before selling the vehicle for $2500, kind of an expensive half dozen times but it is what it is.
I did have the A/C go out on my new '13 Leaf within the first 2 years and it was fixed under warranty, apparently a recall for a bad hose or rather a bracket that held the hose allowed the hose to flex too much causing the hose to fail. I believe the bill which I didn't have to pay was well over $500 so ya A/C fixes can get costly, not as easy as a 99c can or two of R12 Freon we used to be able to add in the old days

 

[nlspace]

Trying to figure out how to remove the AC relay next.

There is a relay removal tool but i don't have one; but i think a small flat blade screwdriver can be used to pry them out by alternating sides and corners to lift a very little bit at a time and working around the edges

 

[bobkart]

Yeah I got it out after finding the right size screwdriver.

It runs the same with the relay out, whine and all, so the whine wasn't the compressor, and the relay is at the top of the suspect list.

I just found an aftermarket version locally and am headed out to pick it up.

I'll report back my results after swapping that in.

 

[bobkart]

New relay did not seem to help.

What else 'small' could be the problem? . . . I'm only seeing the compressor itself left as suspect.

 

[bobkart]

I guess low/no refrigerant is still a possibility, although on the way back from the parts store I stopped at the service station and they used a UV light to check for leaks and found none.

And they're scheduled a week or so out. Guess I'll make an appointment anyway. They can only take it as far as saying it needs a new compressor . . . Nissan would have to take it from there. Looks like those are around $1K.

 

[Steelcity]

Selling for $711 on rockauto.com, so about 6738463637 at the dealer. Lol. If u can find out the voltage the compressor operates at and then find the power leads , u could hot wire it and "bump" it for a second to see if its locked up. Have u checked to see if there is any pressure in the system ? I know all ac systems have a low pressure switch that inhibits the start . Gokd luck keep us posted.

 

[nlspace]

There may be another relay and fuse in the PDM or whatever the equivalent is for 2016. i counted 5 fuses and 3 relays involved in the 2012 HAC.

Another check for the relays--try running the heater, since both functions may use the same relay pair controlled by the VCM. If the heater fails also then you still have an issue in the LV side.

It looks like a capacitive pressure sensor that actually measures pressure and outputs a voltage to the VCM rather than the simple hi/lo sensors of ICE cars. Has 3 wires, excitation and return, and signal 0-4V depending upon pressure. You could try disconnecting the sensor connector to see if anything changes or throws an error.

 

[bobkart]

Yeah I tried the heater and it works and shows up on LeafSpy.

My hope is that a failed compressor would throw a code, and since I have no code, my compressor is okay. But not understanding why whatever is the actual problem isn't being detected and reported via DTC. Looking over the HAC part of the manual, they have procedures for dozens of DTCs.

 

[bobkart]

I'm trying to trace back to when the AC was last working. Certainly last summer, and over the winter I used defrost from time to time, and it was clearly working (quickly defrosted the windshield). Does that dehumidifying function of the AC that defrost uses confirm that the AC was working then, or can it still dehumidify without being able to cool?

 

[LeftieBiker]

I'm trying to trace back to when the AC was last working. Certainly last summer, and over the winter I used defrost from time to time, and it was clearly working (quickly defrosted the windshield). Does that dehumidifying function of the AC that defrost uses confirm that the AC was working then, or can it still dehumidify without being able to cool?

If it dries the windshield and windows noticeably faster than does the heat, then the A/C is working at that time.

 

[Learjet]

not one suggestion to follow the Nissan Service manual for troubleshooting?

 

[bobkart]

not one suggestion to follow the Nissan Service manual for troubleshooting?

I've at least cracked that document open (hac.pdf). I just have the 2015 version, but I imagine it applies well enough, at least for this area.
I'll look again for an overall troubleshooting flowchart, but mostly I saw section after section of dealing with this or that DTC (and I have no DTCs).

 

[Nubo]

not one suggestion to follow the Nissan Service manual for troubleshooting?

It's a complex system with major components (auto amp, ac controller, VCM, etc...) designed to be self-diagnosing. Meaning Nissan troubleshooting relies heavily on the CONSULT tool. It might be worth it in this case to at least have Nissan run the diagnostics.

You could try checking some of the "easier" things manually, like sensor outputs, terminal voltages, etc. Kind of a scattershot approach though. Personally I'd stay away from any High Voltage areas. 400V is serious business.

It is odd there are no DTCs. To rule out CAN interference I'd unplug any OBD2 dongles and disconnect the 12V battery for awhile, then start again (without dongle) to see if anything changes. If still inoperative then check again for DTCs.

Here is one page from the 365-page HAC section of the manual, which is a companion to the 121-page HA section.

 

[nlspace]

That is quite a long list of malfunctions that can prevent the compressor from operating, which makes me think that the compressor is not likely the culprit, i.e. not the first thing to change out. Oddly missing from that list is input signal from the pressure sensor. Also odd that you have no DTCs.