Apparent Air Conditioning Failure

nlspace said:

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.

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It sure seems like some problem condition (on that list or not) is preventing the compressor from running. If not lack of refrigerant pressure, then perhaps a faulty sensor.

I tried disconnecting/reconnecting the 12V battery today . . . no change in symptoms . . . still no HVAC-related DTCs, still no energy usage in LeafSpy with AC on.

I appreciate everyone's help.

The clutch on the compressor is probably toast. That means all the AC components will need to be replaced. That's what always happens to my AC anyway.

Consider running your AC periodically through winter for a few minutes.

I redid the entire AC system on my dodge cummins-- wasn't too bad. Saved $1,000.

https://www.youtube.com/watch?v=bVYUzp8QQ0M

jkline said:

The clutch on the compressor is probably toast. That means all the AC components will need to be replaced. That's what always happens to my AC anyway.

Consider running your AC periodically through winter for a few minutes.

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Thanks for weighing in, jkline.

It's an electric compressor (rather than belt driven), so there's no need for a clutch: just provide electric power to it when compressing is called for.

On the winter point, I believe the Leaf's 'Defrost' function uses the AC compressor to dehumidify the cabin air. So a Leaf's compressor typically will not sit unused all winter.

Update: local shop called back to say they would not have the right refrigerant for a recharge, suggesting the dealer instead.

I made an appointment for next Tuesday with the dealer where I purchased the Leaf. I heard $170 to diagnose and $270 if that leads to a recharge.

We're hitting triple digits here over the weekend, rendering this Leaf unusable.

bobkart said:

. . . still no HVAC-related DTCs,

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i skipped over this earlier, but are you getting some DTCs? If so what are they?

A fault can sometimes affect more than one system and the DTCs are just pigeon holed into different bins for techs using the Consult tool and the FSM for troubleshooting.

I have two 'long-term' DTCs, one is for the passenger air bag problem (apparent OCS failure), and the other is BCM-related, due to my having removed the VSP-generator box behind the glovebox (for weight savings). The air bag DTC have been there for over six months, and the BCM DTC has been there nearly 18 months. I used the AC last summer and over the intervening winter, so I feel that I can rule them out as being responsible for this AC failure. The air bag DTC can't be cleared, and the BCM DTC does briefly clear but comes back on a re-read of the DTCs.

B00A0 0009 AIR BAG
U1000 0009 BCN CAN Comm Circuit

I suppose putting the VSP-generator box back in is worth trying . . . I'll probably do that just so the dealer can't point to it as the cause of the AC problem.

jjeff said:

not as easy as a 99c can or two of R12 Freon we used to be able to add in the old days

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A pound of the refrigerant in the LEAF leaked to the air is about equivalent to 1,400 pounds of CO2

"BCM DTC does briefly clear but comes back on a re-read of the DTCs."
The a/c auto amp not communicating with BCM would set a U1000 according to alldata.com.

Shop can quickly sort this out by doing a auto amp bypass test to see if compressor comes on.

cje said:

"BCM DTC does briefly clear but comes back on a re-read of the DTCs."
The a/c auto amp not communicating with BCM would set a U1000 according to alldata.com.

Shop can quickly sort this out by doing a auto amp bypass test to see if compressor comes on.

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Interesting. So there is some overlap regarding problem areas and codes. Thanks for that information.

I tested the removed OEM AC relay and it passed. I swapped it back in for the aftermarket relay (NAPA brand) and tested the aftermarket relay . . . it also passed.

I re-installed the VSP generator and the BCM code has gone away, but a new VSP code is present (and won't clear). Probably due me having removed the VSP speaker (for weight savings).

B2741 0009 VSP

But the AC still won't work. And it's hard to see how the absence of the VSP speaker could be related.

"Interesting. So there is some overlap regarding problem areas and codes."
Believe so since you reconnected the VSP and U1000 doesn't reset.

It's not the right year but may give some help for where to look; interesting that the heater is commanded over a single wire of a LIN buss, but the AC compressor is on a full duplex UART serial buss. Neither of those are on the CAN buss. If you want to save some money you could find all these connectors and open them up and inspect for corrosion, spray contact cleaner and put them back together. Or just pay the shop rate for the tech to do it. A big culprit in automobile electrical problems is loose, corroded or broken contacts in connectors. When they work all is great, but when there is an issue it can be hard to find. Good Luck to you in solving this issue.

cje said:

"Interesting. So there is some overlap regarding problem areas and codes."
Believe so since you reconnected the VSP and U1000 doesn't reset.

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Right, just hoping to eliminate the U1000 code as being related to the AC problem. Seems not to be, as the U110 code is gone now but the
AC still doesn't work.

Of course there could be more than one reason why the AC doesn't work, so at best I've eliminated one of them.

Thanks for your help.

nlspace said:

It's not the right year but may give some help for where to look; interesting that the heater is commanded over a single wire of a LIN buss, but the AC compressor is on a full duplex UART serial buss. Neither of those are on the CAN buss. If you want to save some money you could find all these connectors and open them up and inspect for corrosion, spray contact cleaner and put them back together. Or just pay the shop rate for the tech to do it. A big culprit in automobile electrical problems is loose, corroded or broken contacts in connectors. When they work all is great, but when there is an issue it can be hard to find. Good Luck to you in solving this issue.

Click to expand...

That's quite a diagram! Thanks for posting that. I may move somewhat in the direction you outline, basically looking over every connector I can easily find. Need to pick up some contact cleaner. I also thought I could at least test for 12V on one side of the AC fuse socket, and also confirm that the AC relay 'clicks' when the AC is asked for (they click when I tested them). It's probably safe to open/close connectors when the car is off, but I believe there are some that should have the 12V battery disconnected to be sure not to cause a problem (air bag connectors I think are like that).

The 6-pin AC relay I tested/replaced does NOT click when AC is asked for by pressing the button in the cabin.

According to the above diagram, the SSOFF relay is upstream of triggering that relay. So now I'm wondering where that relay is.

Of course the VCM could just not be triggering one or both of those relays, and it looks like refrigerant pressure sensor is an input to the VCM.

Still, would be nice to know where the SSOFF relay is and test or replace it, just to rule out one more point of failure.

This thread shows the SSOFF relay right next to the AC relay:

https://mynissanleaf.com/viewtopic.php?t=21647

Digging into that thread now.

Looks like there's more than one SSOFF relay:

"The VCM SSOFF is located in the IPDM E/R, on the other side of the car."

bobkart said:

The 6-pin AC relay I tested/replaced does NOT click when AC is asked for by pressing the button in the cabin.

According to the above diagram, the SSOFF relay is upstream of triggering that relay. So now I'm wondering where that relay is.

Of course the VCM could just not be triggering one or both of those relays, and it looks like refrigerant pressure sensor is an input to the VCM.

Still, would be nice to know where the SSOFF relay is and test or replace it, just to rule out one more point of failure.

Click to expand...

For what it's worth, It's referenced numerous times in the 2011 manual.

No luck under the hood . . . on the driver side I have the two long/thin fuse/relay boxes and that square upside-down one (components installed in the top part). Nothing marked SSOFF.

Searching the HAC.pdf and VC.pdf documents for SSOFF doesn't yield any hits. Fairly stumped.

If the heater works, then the SSOFF relay is probably okay by that diagram, but not sure if it is the same for your year. The AC relay should click with a heater command. And the blower fan motor would likely work with the heater but not the AC.

The VCM commands the AC relay, and the pressure sensor is the main input to the VCM related to AC. You mentioned earlier that there may have been a leak in refrigerant near one of the service fittings, so maybe there is no pressure in the system. i would find and check/clean the connector to the pressure sensor; and maybe try the AC with the connector off to see if a code gets thrown. Then any AC shop with AC gages could check the system pressure, but if it takes special freon then hopefully the dealer has the right tools and materials to check and recharge the system. Maybe there is no DTC for low or no freon--the system just quits with no warning or code?

Lots of error codes for the a/c system according to alldata.com.
P31EE references the pressure sensor.
Dealer scan tool may be the only way to read these.