steev

Hey everyone,

It seems my 2007 RDX, about 16 months old with 9100 miles on it, has a problem with the AC. I noticed yesterday when I was driving on an errand. To confirm this, I tried setting it to LO temperature, then turned the AC on and off a few times, and other than the fan speed changing, I could not tell the difference between fan-only and A/C.

Is there anything simple I can check myself before bringing it to the dealer? Are there any conditions under which I should expect the AC not to work?

TIA!

Carbon2008RDX

Unless the outside ambient temp is below 58 degrees the A/C should work for cooling, and it's definitely not 58 degrees yet in the NYC area! I would check your fuses. If the fuses seem OK then it's a trip to the dealer, unfortunately.

steev

Thanks Carbon. I'll try taking a look at the fuses. Anyone have a clue which fuse is for the AC?

The wierd thing is that the fuse chart is confusing, I don't see any obvious fuses for the AC but there are a few suspects: on the interior panel, #3 is "ACG", #36 is "HAC". Nothing is clearly marked Condenser, A/C, or Climate so I will take a peek at those two first.

I prefer not to pull out each fuse if that will cause trouble with other things being reset or whatever...

TIA

737 Jock

steev,

Here is how to run the Climate Control System self-diagnostic function:

A) Turn the ignition switch ON (pos II, do not start the engine).

B) Press and hold the Climate Control OFF button. (To right of AUTO, beneath DUAL).

C) While holding the OFF button, press the rear window/mirror defogger (left of MODE, above A/C) 5 times within 10 seconds.

D) Release the buttons. Self diagnostic will begin within 20 seconds.

If a fault is detected the driver temp indicator and AUTO indicator (on display beneath windshield) will flash a code. The temp indicator will flash one or more segments of it's 14 display segments that form 88, and the AUTO indicator may or may not come on with it. The temp indicator will alternate every second between the segment code and 88. For instance you may see -/88/-/88/-, and the AUTO indicator may be on or stay dark. Note exactly which segment or segments flash, and if the AUTO is on.

Look at this diagram:



Post the result and I'll look it up for you. (If no fault is detected the displays will remain dark.)

To exit self-diagnostic turn the ignition switch OFF.

vrflyer

Sounds like a possible punctured condenser, something to consider....

steev

I tried the diagnostic test and there was no error code.

I took the car to the dealer and they said the coolant was low, they couldn't find any leak but supposedly they put a dye in when they refilled it so they can find the leak if there is one...

sandstorm

Sorry for the tread revival, but after a lot of search I am unable to find out the information I an seeking.

I have an 07 RDX and air venting system is stuck to ''feet'' I am unable to get air anywhere but ''feet'.

I try the Climate Control System self-diagnostic as stated above. I am getting ''A'' with no ''Auto light''.

I would like to know the meaning of this fault code and/or if someone have an idea of my problem

thank you

dcmodels

AN OPEN OR SHORT IN THE MODE CONTROL MOTOR CIRCUIT (see page 21-47 of the FSM 2007-2009 Vol 2 first edition 06/08)

That page contains a test procedure for DTC B1239 or DTC indicator A, which you may wish to pass-on to your dealer.

That page also contains a redirect to page 21-86 which is a test procedure for the MODE CONTROL MOTOR.

And page 21-47 also contains a procedure for testing the CLIMATE CONTROL UNIT CONNECTOR A (24P).

And that is why detailed info is difficult to pass along over the internet, and why you may wish to consider purchase of a FSM (factory service manual), assuming that you are able to perform the diagnostic tests yourself, or at least wish to garner more info before visiting your dealer. Just be aware that most test procedures involve use of the special Honda HDS (Honda Diagnostic System) test device.

In this particular case, you can probably test the connector simply with a digital VTM (volt / ohm meter). Not so sure about testing the MODE CONTROL MOTOR.

Good luck, and let us know what was the problem, when you get it fixed.

Mr Marco

Geez. Lots of free advice here on the A/C cooling system from the peanut gallery. Diagnosing the real issue with your cars A/C system is very complicated.

-If there is a leak you need a special fluorescent die added to the system to find it.
-Could be a bad switch, rely, fuse, or wire.
-Compressor may be seized or seal may be bad.
-Evap/condenser unit may be bad.
-etc.

What I'm trying to say is if the system is not working it is very difficult for the average person to determine exactly what the issue is. Therefore, you should take your car to the dealer. They have the right tools and equipment to properly work on your car.

Also the A/C system in the RDX is only good for about a 20deg drop, so if it is 105 outside it would be 85 inside the vehicle.

737 Jock

Well sandstorm, thanks to dcmodels your fault is identified. As he said, the first check for Open or Short in Mode Control Motor Circuit is to test the Mode Control Motor. I went to read that test and found an interesting note.

It says to apply battery power to the Mode Control Motor to see if it runs. However if it doesn't run the next step is to check the mode control linkage and doors for sticking or binding, repair that and then the motor should run smoothly. This is important because the RDX has a history of sticking and binding in the climate system doors. That is the "groaning" sound on start-up that is very well documented on A-zine.

While this doesn't rule out electrical faults, the known history makes a stuck mode control door the most obvious reason for your Mode Control stuck on footwell air. It is also the simplest and quickest thing to fix. There is a TSB out to grease binding Mode Control doors. I think you can find it on this sight.

Your warranty is probably close to expiring. Certainly, do not let your dealer or shop charge you to replace a Mode Control motor or doors, if lubricating is all you need.

I hope this helps you resolve your problem. Let us know how it goes.

Below is from a previous post:

Mr Marco

^If your car is still under warranty and you try to diagnose the issue youself, be careful not to break ANYTHING. Don't even strip a screwhead. Otherwise the dealer will not take your claim.

Take
It
To
The
Dealer.

ozwaldo

737 Jock - I did the test and my result is that L and auto were both lit.

As for symptoms.... My AC seems week, slow to cool, but eventually gets good enough. Also every few weeks I get "smoke" coming from the vents. Turning the AC off and back on after about a minute will stop the smoke. So, I think something is going, hopefully the code will help to show what it might be.

Mr Marco

^ So once you have diagnosed the issue (bad/leaking evaporator cooling unit - leaking heater core), what's your plan to fix it? You do not have the necessary equipment to fix it.

Freon recovery machine $2,500-3,130
Dealer a/c work $800-1,200

737 Jock

The "L + Auto" lit indicates: Fault in the Driver's Air Mix Control linkage, door, or motor. This is similar to sandstorm's problem with the Mode Control Motor and linkage. The first check is to determine if the motor runs. If not, then check/repair the driver's linkage/door.

As in my response to sandstorm above; it is more likely that the door and linkage is binding as that is a known problem. There is a TSB out to grease the Mode Control doors, and it is reasonably likely that is all you need.

You have no other faults recorded, such as leaking refrigerant, so your A/C may be slow to cool simply because of the stuck door. If the airflow feels normally cold or reads about 40 F with a thermometer in the vent, then the rest of the system should be OK, and you are not in need of any refrigerant service. (You can also have the refrigerant quantity checked in about 15 minutes at any reputable shop.)

The "smoke" however is a whole 'nother thing! What do you mean by "smoke". Is it just visible water vapor -- cold with no odor? Or is it electrical smoke -- warm with an acrid electrical odor?

Big difference! Cold water vapor may be due to the blocked off duct. Electrical smoke requires immediate attention.

737 Jock

Also, as the Driver's Air Mix Control door is not moving as it should, then the driver side ducts are combining hot air from the heater core with cold air from the evaporator. This would explain why it doesn't cool as quickly.

With the driver/passenger temp controls both set to the same degree, compare driver duct temp to passenger duct temp. Higher temp on the driver side, would verify the air mix door is stuck, or binding. As the car is run for while, the air mix door may unbind and move towards the commanded position allowing colder air through the driver duct.

ozwaldo

Thanks 737 Jock.

The "smoke" is cool and without an odor, so I think the TSB will be my fix.

I will let you know for sure after my next service.

Mr Marco

Good luck Waldo...

737 Jock

Now that you've isolated your problem to the Driver Air Mix Contol, you can further identify down the fault by using this procedure from the post above:

"In Dual Mode; run the driver temp up and down and listen for the noise (driver air mix door)."

You can determine for yourself how much the door is binding, by listening for it's movement and checking the change in duct temp.

Service Advisors often know very little about cars, and tend to tell you anything they think you will believe. Bring a printout of the TSB and you will be well informed and prepared when you go in to the dealer.

inquisitivetiger

Looks like I have this very same issue. The wife took the car for a spin and found that the RDX started to just blow air. When driving the car would blow hot air. I ran the Climate Control System self-diagnostic function and found no errors.

My 07 RDX has only 25k miles so it is a bit disappointing that the A/C is out. Not only that, it has been 100+ degrees for the entire month in Texas.

If you had a similar issue, what was your resolution? Mine is out of warranty and I have not checked the fuses yet. Intend on getting a freon refill with the dye, but it would be great if there were any additional checks that I can do before I bring it in.

Thanks!

737 Jock

That is the initial self-diagnostic that checks for shorts and opens in the sensor circuits, the air mix control motor circuits and doors/linkages, and the climate control unit's internals and communication. So the good news is that all of that's OK.

But it does not check the A/C signal circuit sensors. For instance the evaporator temp sensor or the vent temp air out sensor (TAO) could be sending inaccurate readings that make the computer think A/C is not called for.

Nor does it check the A/C freon pressure sensor. This sensor tells the computer to shut off A/C if it thinks the pressure is too high or low. It might be sending an inaccurate signal or the pressure might actually be out of range (ie, freon leak). To test these, see the additional self-diagnostic checks referenced below.

Bad circuitry is always a possibility, but this sounds more like a refrigerant leak. Have your wife start the car and turn on the AC while you are listening and watching under the hood. The refrigerant pressure sensor should stop the AC compressor from running if it senses low refrigerant.

Can you hear the AC compressor engage?
Look at the drive belt tensioner. Can you see the drive belt/tensioner jump a litle when the AC compressor engages?
Do the electric cooling fans run loudly every 20 to 30 seconds?
Any abnormal noises?

Additional Self-Diagnostic Checks:

There are further procedures you can do in your driveway to check and test the signal circuit and pressure sensors listed above (more sequenced button pushing) but it runs several detailed pages. Let me know if you are interested.

Otherwise, perhaps take it to a shop with a Honda Data System (HDS) and communicate with the car and check the freon with a refrigerant charging station.

RDX Refrigerant Capacity:
0.45 to 0.50 kg
1.0 to 1.1 pounds
15.9 to 17.6 ounces

inquisitivetiger

Thanks for the additional information. Just spoke with my local shop and he called his brother in law who is one of Acura's Service Managers. The SM mentioned that they have been getting a few RDXs in for issues with the compressor coils lately.

I wonder if it may be better to just find an extended warranty for the RDX anyhow since replacing the compressor would run around $500-$1200. Does anyone know how it works at Acura after warranty? Do they charge just to look at the car and diagnose the problem? The local shop would charge $95 and waive if I continue to get the problem resolved with them.

inquisitivetiger

The options on the extended coverage was received and it may be worth if more road debris or other electrical issues come about. Which would be most desirable? I think I currently drive between 7k-9k a year. Any other major issues that you have faced so far with your RDX?

AcuraCare
3 years
100k miles
Coverage through 8/31/2014 or 100000 miles
$1335

4 years
80k miles
Coverage through 8/31/2015 or 80000 miles
$1245

5 years
80k miles
Coverage through 8/31/2016 or 80000 miles
$1275

737 Jock

Withour a warranty, it's a good bet that any shop will charge you to hook up to their HDS and refrigerant charging station. Then they will have to track down any DTCs (trouble codes) and the source of the leak or low pressure (labor hours).

Most extended warranties have a waiting period before they are effective, to prevent people from trying to claim a pre-existing fault. It sounds like your local shop might be offering a work-around on that -- but find out first.

I don't buy extended warranties on anything -- just do my own repairs as needed. The RDX is by far the most trouble free of the 30-some cars I've owned. The underside is tight and dry. I've replaced 2 door speakers, a worn console cover and a shock damper over 97000 miles.

737 Jock

For about $40 you can recharge the system yourself with dyed freon and check for leaks with a UV light.

Here's a link to detailed article and DIY: Air Conditioner Refill and Leak-check

It's not needed to pull the wheel liner like they do in this DIY. On the RDX the service port is on top. If you do this, research it thoroughly and be extremely careful. The pressure gauges on the cans are less accurate than charging stations that weigh the freon. Improper freon levels can make things much worse!

737 Jock

If the AC compressor doesn't engage:

Check fuse #20 (7.5A) in the under-hood fuse/relay box

Check fuse #36 (10A) in the under-dash fuse relay box

VietNinjaJ30A1

Hmm I just had to have my A/C repaired...well...replaced. It's funny that someone mentioned a Service Manager saying they've gotten quite a few RDXs needing need compressor coils. That's ONE of the things I needed. My compressor had been damaged by heat, so I needed a new one of those plus clutch and coil. Then my damaged compressor was depositing metal shavings in the lines which ended up in my condenser...so I needed on of those too. Out of warranty. Fml.

My A/C does make the groaning sound though...and I wish it'd stop.

defajardo

The a/c coil going out sounds about right. I called my dealer and the service guy confirmed it's "very" common.

737 Jock

AC compressor field coil part# 38924-RWC-A01, about $75.

The book says to remove the compressor to replace the field coil, which then requires a refrigerant recharge.

But it looks like it may be possible to pull the field coil with the compressor on the car. They do it that way on the RSX forums, without venting the refrigerant.

ozwaldo

Finally took her in for a service today and they say it's time to replace the driver side air mix motor - which matches the code I was getting a few posts ago.

For $177 I can have cold AC again, just in time for winter.....

They also noted that my front passenger axle seal has a slight leak - something to keep an eye on

inquisitivetiger

Mine was the fuse under the hood... The part was only 5 bucks.. they charged me $300 to take care of that and two speakers..

737 Jock

^^ Yikes! Sorry it didn't go better, but thanks for posting your experience.

For future reference; fuse replacement is about the easiest trouble shooting there is. It's cheap and anyone can do it.

Also here is a guide to speaker replacement -- fairly easy as well: DIY - Remove Door Panel and Replace Speaker

ray1031

So if I understand correctly, if the AC quits blowing cold air it's either because of a leak or the car is checking status of it? I just purchased an '07 and 2 times when my kids were riding in front with my wife messing with the controls the AC would not blow any cold air and out of the blue after a while it would start working properly.

737 Jock

^^

I looked that up for you in the Service Manual.

ray1031

Lol

02SLVRSXS

Honda AC Compressors are junk.

Very high failure rate out in the field. Honda has not done anything to correct it even on new models, because like Toyota, they can do no wrong.

Discflite

How do I accrue posts??

DRR98

Well you just did. Useless post, but still a post.

northcarolinagirl1234

My A/C quit working on a hot day. However, if it cools down outside (around 77 degrees), it works fine. As soon as the outside temp increases and my RDX sits in the sun for any length of time, I don't have cool air. It blows warm air. Any experience with this or advice? I've already taken it in once and they added freon and a dye to check for leaks. It went out again and took it back and it indicated no leaks.

DRR98

^ Read thru post #32 above for some troubleshooting details.

pwu_1

1) check the 2 relays in the engine compartment(there are 2 with the snow flake icon)
2) check the field coil on the compressor.
The symptoms sounds like the field coil from what I have read. The AC works fine but when outside temps gets hot like above 90 degrees, AC stops working. Once it cools off outside, AC works again.
If it turns out to be the field coil, I believe Acura extended the warranty on the field coil to 100K miles so it might be covered under warranty.