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Discussion Starter · #1 ·
Hello. It is so hot and I guess I forgot that last summer the ac in my car 2016 Nissan Altima S 2.4L did not seem to keep cool. Yesterday I drove 600 miles to south Texas and A/c cooled sometime and sometime not. When I got back I put my gauges on the low and the high side and got no psi. I started the car up and let it run and let ac engage and warm up anyhow i know that you have to have the valves closed until you are ready to check the psi and still nothing. So i went up to Oreilys bought one of those can kits with a gauge and came home and tried to put in the freon but it would not take any so I thought something was wrong with the gauge of the can that i bought and went back up there. The guy seem to know what he was talking about he told me that the compressor was overpressurerized and he let air out of the port and it was air not freon until the last bit which was the very last bit of freon in the system. And then he put in a half of a can. Ac no longer blows any cool air only hot air. At least before I started messing with it, there was still some cool air. Anyhow, SO I have been investigating and I find out about the Control Valve that is on the bottom of the compressor and since my compressor and my car has high mileage., I suspect it is bad. I have ordered one and when it comes in I know I will need to recover the freon before taking it out and putting in a new one, but I started thinking well maybe it is the expansion valve. So I ordered an expansion valve kit that comes with a drier, orings, expansion valve and oil. But, I cannot find the expansion valve, Is it attached to the heater core and if so, how difficult is to get to it? Or is it out there on one of the lines and I have to remove the strut tower brace to access it? Anyhow, I drive for a living and it is too hot to drive my car with no AC please help.
 

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It's attached to the front of the evap where the A/C lines go through the firewall. It's 92200M in this parts diagram:
Line Font Parallel Schematic Engineering
o
BUT, you may be choking your own chicken playing around with canned freon. The system has a pressure sensor and not switches, and the ECM won't let the compressor come on if it shows either low or high pressure. The great likelihood is there's nothing wrong with your hardware that a proper evac and recharge won't fix.
 

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Discussion Starter · #4 · (Edited)
It's attached to the front of the evap where the A/C lines go through the firewall. It's 92200M in this parts diagram:
View attachment 8851 o
BUT, you may be choking your own chicken playing around with canned freon. The system has a pressure sensor and not switches, and the ECM won't let the compressor come on if it shows either low or high pressure. The great likelihood is there's nothing wrong with your hardware that a proper evac and recharge won't fix.
Thank you for clarifying that but, I also have diagrams but physically on the car, is where I am trying to find it. Is it in the center behind the motor where the high side line is hooked to? or is it over to the left passenger side, . What is that silver block thing that is over on the left side on the firewall that has all of the lines going to it? I will most likely not replace it. I will most likely replace that control valve in the bottom of the compressor after having refrigerant evacuated then recharge it. The kit comes with a drier and i did not know if I needed to use that in some way. I agree that you are most likely correct in that it needs a proper evacuation and recharge, the issue is that I do not have a trustworthy mechanic and most likely any shop or dealer will tell me I need to replace compressor. But, why would the freon leak out? Can you identify or provide the page that identifies the other items on this diagram?
 

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The TXV is that "silver block thing that is over on the firewall that has all of the lines going to it". The A/C has a swash plate compressor and the HVAC, BCM, ECM and IPDM all need to agree and function properly before it will turn on. Frankly, if you know that little about the system, I strongly advise you skip the suicide cans and tell a repair shop, "Screw the compressor, just recharge it and tell me if it leaks." If it does leak or still doesn't work right after an evac and recharge, then try other things.
 

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Discussion Starter · #6 ·
You are exactly right. Just because the parts are on the way does not mean I have to put them on yet. Thank you for suggesting that. I was going to go pay for them to evacuate, come home change the part and then take it back and recharge. But, what you said makes more sense. Thanks
 

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Discussion Starter · #8 ·
You're most welcome. Let us know how it goes.
SO, I replaced expansion valve on Saturday night and then Monday morning took it to this place to have them proper vacuum and recharge. Problem is that he did not do that he put the gauges on and low side he said was 50 L and 150 H and I was standing right there and I thought both low and high side read around 35. Also, I thought the low side should be reading close to what the outside temperature is. Anyway, it got cooler after recharge but it did not last because I do not think he vacuumed it out. He told me I had a weak compressor and that if i was going to replace it, that i also needed to replace the condenser. I am not buying that because today i still had 60 degrees coming out of vent it is 95 plus degrees here. I would think that if condenser was clogged or bad that the ac would not work at all. If my ac was working right what would the low and high side pressure be. ? I am telling you, I doubt I can find a mechanic i can trust. I will most likely replace the compressor myself. SO i went back to that shop today just to see if he would put gauges back on and see if it read the same pressure. He told me that it did read the same pressure but that he had run out of freon and that it was just a little bit low.
 

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Say 25~40 low and 150~175 high depending how hard the compressor is working. Without a proper evac you'll never know if moisture is causing your issue. If you must DIY it, then a cheap pump and gauge set doesn't cost a ton. With a little shopping you can find one for under $100 anyplace.
 

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Discussion Starter · #10 ·
Say 25~40 low and 150~175 high depending how hard the compressor is working. Without a proper evac you'll never know if moisture is causing your issue. If you must DIY it, then a cheap pump and gauge set doesn't cost a ton. With a little shopping you can find one for under $100 anyplace.
My friend has a vacuum pump and I have a set of gauges but, they are harbor freight and have been used i think twice and have already failed. I think I may have a brand new vacuum gauge unless it is a pressure gauge I will have to look . Thanks for ter the ebay suggestion
 

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Discussion Starter · #13 ·
If you plan to DIY the AC system, here's a chart that may help:



BACK TO THE AC FOR A MINUTE. Okay, I know my Nissan AC has 262k miles on it. I am suspicious that it may be weak because it still works but only intermediate and sometimes it works right off the bat and at idle and then it does not work. But, since it has been acting up, the temp at the vent only goes down to 58. So I know it is not working right. I know that I need to replace the compressor before it fails and messes everything else up. The service manual says to start with a Self Diagnostic Test to see if there are any codes. I remember some sort of test like that but, I have a Blue Driver and there is noting unusual that I can see in regards to ac system however, I know there are no codes when scanning it and the live data looks pretty normal. Would the AC throw a code? What is the self diagnostic test?

View attachment 8884
 

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Discussion Starter · #14 ·
My friend has a vacuum pump and I have a set of gauges but, they are harbor freight and have been used i think twice and have already failed. I think I may have a brand new vacuum gauge unless it is a pressure gauge I will have to look . Thanks for ter the ebay suggestion
I figured out how to do the self diagnostic but it does not complete. It just stops and stays in the mode and interrupts when I open the door. So I got my Blu driver to scan codes. I have 3 and all three are valid. DEALERSHIP had the recalls to do when they replaced the tranny but did neither one of them. One is B26FE hood switch one is B0020 airbag deploy and a new one C1706 flat tire on left side which is odd as it actually the passenger side back tire which may be considered to be left side back tire is low . No other codes and because the self diagnostic does not complete it makes me wonder if the I-Key system error is causing it to not complete. I had at one point lost my only remaining oem key fob and when I called to have it replaced per dealership for an aftermarket they came with a 5 button key for instead of a 4 button and told me after I paid them already and after they had left that I would have this error because key was an aftermarket key. Since then I found the oem key fob but have not had that one programmed. So idk if I am getting any codes for ac but since I cannot tell or seem to not, I guess I need to start tearing into the system wished I had a Nissan Consult but oh well.
 

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If the hood latch recall was done, the B26FE could be from the hood switch connector being un-seated or loose from a careless tech. Pop the air intake loose (two 6mm screws) and check the connector. The B0020 is, unfortunately, almost certainly broken or pinched wires for the side airbag in your driver's seat. It's a common problem on gen5 Alties and the only solution a repair shop can give you is to replace the entire seat back. The wires are actually part of the airbag and not the car harness, and due to legal concerns, no professional shop will repair or replace them. If your tire isn't actually flat then the C1706 means your sensor's measurement circuit is either plugged or inoperative. The sensor has to be "talking" or you'd be getting a "no data" DTC and not a flat. None of those codes can possibly affect the A/C.
 

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Discussion Starter · #16 ·
If the hood latch recall was done, the B26FE could be from the hood switch connector being un-seated or loose from a careless tech. Pop the air intake loose (two 6mm screws) and check the connector. The B0020 is, unfortunately, almost certainly broken or pinched wires for the side airbag in your driver's seat. It's a common problem on gen5 Alties and the only solution a repair shop can give you is to replace the entire seat back. The wires are actually part of the airbag and not the car harness, and due to legal concerns, no professional shop will repair or replace them. If your tire isn't actually flat then the C1706 means your sensor's measurement circuit is either plugged or inoperative. The sensor has to be "talking" or you'd be getting a "no data" DTC and not a flat. None of those codes can possibly affect the A/C.
Tire is not flat only a little low I can fix that easy. I was thinking that the hood latch had a recall as well as the airbag but it may be for something else and not what I am having an issue with.

The rental gauges I got at autozone are junk I ordered this thing it will not be here until tomorrow. dang it.
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Discussion Starter · #17 ·
If the hood latch recall was done, the B26FE could be from the hood switch connector being un-seated or loose from a careless tech. Pop the air intake loose (two 6mm screws) and check the connector. The B0020 is, unfortunately, almost certainly broken or pinched wires for the side airbag in your driver's seat. It's a common problem on gen5 Alties and the only solution a repair shop can give you is to replace the entire seat back. The wires are actually part of the airbag and not the car harness, and due to legal concerns, no professional shop will repair or replace them. If your tire isn't actually flat then the C1706 means your sensor's measurement circuit is either plugged or inoperative. The sensor has to be "talking" or you'd be getting a "no data" DTC and not a flat. None of those codes can possibly affect the A/C.
I have not seen a weird looking sensor like the SUN SENSOR or the Climate COntrol Sensor Where are they physically located?
 

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Discussion Starter · #18 ·
If the hood latch recall was done, the B26FE could be from the hood switch connector being un-seated or loose from a careless tech. Pop the air intake loose (two 6mm screws) and check the connector. The B0020 is, unfortunately, almost certainly broken or pinched wires for the side airbag in your driver's seat. It's a common problem on gen5 Alties and the only solution a repair shop can give you is to replace the entire seat back. The wires are actually part of the airbag and not the car harness, and due to legal concerns, no professional shop will repair or replace them. If your tire isn't actually flat then the C1706 means your sensor's measurement circuit is either plugged or inoperative. The sensor has to be "talking" or you'd be getting a "no data" DTC and not a flat. None of those codes can possibly affect the A/C.
Okay I will stop pestering you for now. I found the sun load sensor I hope that it is not covered up on my car and causing these issures
 

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They're covered up all the time in the shop (and they always throw a temporary code when indoors). It doesn't affect anything, the Sunload Sensor can only increase the A/C output in bright sun, not reduce it in other circumstances. It definitely isn't causing your issue. There are at least 2 and maybe 3 sensors that can:
1) Ambient - It's up in the grille. Easy to check, if your outside temp in the cluster reads "Alaska" then it isn't working.
2) Intake - It's mounted on the evap but there's always an intervening connector someplace on the HVAC housing where you can check it.
3) Cabin (In-Car) - It's on Auto A/C systems only, Manual A/C's don't have it. It will be behind a small grille in the plastic at the driver's right knee.
Since all the sensors are "balance" circuits where the sensor pulls harder to ground as it gets warmer, an open circuit always reads 5V (no ground at all) and that equates to "Alaska". So they're all easy to check. Take the sensor connector loose and short the pins to make it read "Death Valley" instead of "Alaska". If the A/C wakes up, then you've found your problem.
 

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C1706 flat tire on left side which is odd as it actually the passenger side back tire which may be considered to be left side back tire is low .
When you move tires around, the TPMS system doesn't follow the tire that was moved so it thinks the left tire is low on pressure. For the TPMS to work right, you would have to re-register the tire sensors.
 
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