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Hi All, My wife and I just bought our first Honda Pilot. It is a 2011, the A/C is not working, I connected my code reader I am getting the following codes: B1233, B1236, B1239, B1244, B1245, B1246, B2979, B2965 and last U1064. I am actually a mechanic by trade but do not have any information for Honda diagnostics. I have read that Hondas have a known problem for A/C relays but could the relay cause all of these codes. Thanks in advance for any help in my situation. By the way I bought it from a used car lot and they are going to pay for repairs I just wanted information I know how shops can be. Thanks again Tom
 

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Hi All, My wife and I just bought our first Honda Pilot. It is a 2011, the A/C is not working, I connected my code reader I am getting the following codes: B1233, B1236, B1239, B1244, B1245, B1246, B2979, B2965 and last U1064. I am actually a mechanic by trade but do not have any information for Honda diagnostics. I have read that Hondas have a known problem for A/C relays but could the relay cause all of these codes. Thanks in advance for any help in my situation. By the way I bought it from a used car lot and they are going to pay for repairs I just wanted information I know how shops can be. Thanks again Tom
Welcome to the Forums! you are correct the Relays are a hassle time to time as you are already away..hope they fix the issue for you.
 

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I am getting the following codes: B1233, B1236, B1239, B1244, B1245, B1246, B2979, B2965 and last U1064.
Did you find what these codes are as yet?
I tried to look at a site referenced here:
https://www.piloteers.org/threads/for-reference-lists-for-trouble-codes-obdii-dash-generic-honda-specific.163849/
but did not find them at first try as I saw only a B0XXX list. The site may have a separate list for the B1XXX codes, or you may search online for another source. Let us know what you find?
Normally though, a scanner advanced enough to read Honda-specific codes, will have a lexicon entry showing their meaning (?)
 

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I've been searching myself the codes I have recently received from a friend who pulled them via SureTrack. Codes are as follows:
B1233 - An Open In The Driver's Air Mix Control Motor Circuit
B1234 - A Short In The Driver's Air Mix Control Motor Circuit
B1236 - An Open In The Passengers Air Mix Control Motor Circuit
B1239 - An Open Or Short In The Mode Control Motor Circuit

I find it hard to believe that both my air mix control motors are bad at the same time but its certainly possible. Unfortunately, I have another issue requiring replacement of the main thermal expansion valve before I start swapping suspect air control motors. Issue is that after running AC a short amount of time, the drivers side begins to blow hot and shortly after the passenger side follows suit but the rear AC remains cold. Gauges show good pressure on the high side but a vacuum on the low side indicating a blockage. Hope to replace this weekend and with some luck, get that part of the problem resolved. If anybody has anything else to check for, I'd greatly appreciated it!
 

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I just had my front expansion valve replaced after have similar issue to you. For the mix motors, I would inspect their operation after you get the txv done. If they are not responding to calls for heat, then they are easy to replace.
 

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Problem solved..It appears that after replacing the front expansion valve, the issue with the mix motors no longer appeared and I now have very cold AC once again. I also replaced the AC thermistor with new since that was easily accessible and did not cost much to replace. Pic shows old thermal expansion valve with new one attached.
 

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Glad it is working for you now. Any insight into why these expansion valve go bad over time? It seems to be a simple part. Is it just continued use in a pressurized environment?

By the way, kudos to you for tackling this yourself. I read the repair manual procedure before I hired this out just to be familiar. It is a fairly involved job working under the dash. How long did it take you?
 

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I have no idea how or why these go bad..just that they do. The big indicator that pointed to the expansion valve was the low side vacuum reading (while the high side reading within range) when the AC system was running and after shutting off the engine, seeing that the pressures were not equalizing. They would eventually over time equalize but it should of been a lot quicker than what I was experiencing which seemed like hours vs few minutes.

As for the job itself, it took me a little about 4 hours to do stopping here and there to cool off since it happened to be a hot one that day. After having done it once, I could probably knock it out under 2 hours now that I know where all the screw locations are and having learned a couple tricks along the way. For those who wish to tackle on their own, here are some tips since I could not find any (at least at the time before I did it): Note that these are just tips from what I learned working on my 2011 Honda Pilot and NOT full instructions on how to replace a thermal expansion valve.
1) Find a shop or buddy who can evacuate your freon and then recharge when you get the job done. There is not much to it other than hooking it up to the machine and letting it do its thing. They should not be charging you for new freon (unless you have a leak) since they should be putting back in exactly what they removed.
2) Have an assortment of extensions AND a right angle driver handy. Your hands will thank you later! I used a cordless driver/drill for most all the screws/bolts I removed and re-installed under the dash.
3) Remove the horizontal metal bar at the base of the glove box & peel back the passenger side carpet.This step makes removing the blower motor housing from under the dash a lot easier.
4) After removing the blower housing, there is a screw inside the assembly that needs to be removed to access the thermal expansion valve assembly. Circled in pic below. Other pics shows that same assembly showing all the mounting holes held by self taping screws that need to be removed and the expansion valve in place covered by that removed piece.
 

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