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Diagnosing Aircon Problems

Pedro,

Thank you for the document info. It's a good find. Much appreciated.

Brian,

Thank you for translating the system function. Why is it that it is so hard to get electrical schematics of the Accord diesel? (I see that even Haynes is sparse on the Honda side).
When I transplant the condenser I will confirm the function of that valve (power to open or close).

My gut feeling is the compressor but my head has been trying to avoid it until I have enough facts I guess. I just didn't want to go down the route of changing the condenser and having it recharged only to have to evacuate it again for other works.

Plan now.
1) Get system evacuated
2) Transplant the condenser.
3) Remove the compressor and inspect/replace.

I think I will strip it out to check and just refit if it's faulty until I get a replacement? (Remove the compressor clutch coil relay so it doesn't accidentally get switched on)
I believe the alternator has to be removed to gain access. Is it worth doing the shorter belt mod at the same time? (Read that somewhere).

When I inspect the compressor am I expecting to feel some suction/delivery pressure by simply placing my palm over the ports and spinning the clutch by hand? Or does it have to be quite high speed to feel if it works? Are they easy to strip/rebuild or is it throw away?


Jay
 
Jay, that seems the best plan. I 100% agree with everything you have done so far, I would have done the same, I think it is best to get as many facts as possible until taking action. Also, as you say, somewhere on this forum someone suggested getting a shorter belt to use the car with the compressor removed. I've no idea if this is possible, it might be, again if it were me I would also explore that idea ..... I would prefer to take my time looking at my compressor off the car, and still be able to use the car. I've never removed the compressor on this car, and on other cars I've only swapped the compressor, then stripped the dead one down to take a cursory look before chucking in bin LOL.

btw Matt (mattlee) on this forum might have a useable replacement compressor, try contacting him, he might let you have it very cheap, he never needed it, he got it because a dealer suggested his compressor was faulty just before I wrote this thread, then he did my tests and realised it was his pressure sensor (diesel car). You will not find that thread, it's gone, controversial story (IMO Matt was a victim of circumstance).

I also wonder if we will ever find something as good as Pedro's document for the diesel car. When you have the condenser out, also try to see if that valve is normally open and shuts when energised. Also measure the continuity of the terminals on the pressure sensor, could be useful info for anyone else with a diesel (***uming your pressure sensor is not faulty).

cheers, Brian
 
Update:

I have swapped out the condenser this evening... well 4 hours of swearing. I wish car manufacturers would use stainless fixings on the lower areas, namely the spring type clips with nuts attached that hold the side under tray on. I broke all 4 of these clips and a small piece of under tray. It looks fine but will find some clips to replace them at some point. I bought some 10mm trim clips off the bay in advance just in case the others broke....used 5 so glad I had them, at £2.50 for 10 not bad.

I will try and do a write up with the pics I took by the weekend. It is a simple job if all fastenings came undone easily.

Brian,

I checked the valve out and indeed as you suggested it energises to shut.
valve.jpg

valveseat.jpg


Unfortunately I was struggling to get on the 3 pins for the pressure switch due to it being mounted on the pipe fitting, I was unable to get a good view etc and could not get my test leads on the pins consistently enough to get reliable readings. If you think of the pins as 1-2-3 then 1-2 = 11.4kohm 2-3 = 4.72Kohm 1-3 = 6.68kohm which are pretty whack readings....actually maybe not. Be interesting to test another switch because if 3 was the common then 3-1 =6.68kohm and 3-2 = 4.72kohm therefore the sum of the 2 =11.4kohm. Now I know this isn't normal for switches however is it possible it is a variable pressure sensor???? or is that just amazingly coincidental readings???? Answers on a post card. I will try and make some miniature crocodile leads at work so I can test them easier (luckily I wont have to remove the bumper again.

Jay
 
Replacement pump arrived today so will fit on Friday evening hopefully. On checking it, appears to pump fine. I put a rubber glove over the outlet and sealed it tight. Even just rotating the pump by hand inflated the glove. I did video it and have it on photobucket (sad I know) so just need to work out how to link it here. The interesting thing is you can rotate the input shaft in any direction and it will always pump the one way. The video shows I am oscillating the input shaft quite slowly considering. I now have to look inside the old one....just have to know how it works.
 
Looks good!

Have you tried to do the same with the old one, if you have already taken in out?
 
Not yet. I changed the condenser yesterday and did a fuel filter change this afternoon then the spare compressor turned up. Now I know what to check for I think I can remove this outlet pipe easily without removing the unit. I will try tomorrow after work. If it doesn't (hope it doesn't) then I'll be swapping them on Friday afternoon.
 
The captive nut in the metal clips for securing the lower panel to the front fender rust up, and then the hex head screw snaps off, and a new clip from Honda is £2.41 !!!! I greased all mine when I put them back.

Those measurements on the pressure sensors are strange. The single sensor in the system on the petrol car is definitely a switch as it behaves o/c and s/c. Maybe the sensor on the diesel is a single active sensor e.g. the 3 pins are ...... a ground, a supply input, and a return signal.

Your test on the compressor is magic, I would never have thought of trying that :)

I'm looking forward to your next update !!
 
Yeah I'm not convinced with the switch measurements either. I may make a patch lead so I can test it in situ. One other thing I forgot to mention, when I had the refrigerant sucked out the injector heater coil symbol is now constantly flashing. From what I understand this means that the system has detected the low pressure. I believe it's not in limp mode as the engine symbol is not on. Can't wait to have a look tomorrow.
 
Jayaccord said:
Yeah I'm not convinced with the switch measurements either. I may make a patch lead so I can test it in situ. One other thing I forgot to mention, when I had the refrigerant sucked out the injector heater coil symbol is now constantly flashing. From what I understand this means that the system has detected the low pressure. I believe it's not in limp mode as the engine symbol is not on. Can't wait to have a look tomorrow.
Click to expand...
Matt (mattlee) and Max (Max10) both got the flashing glow plug symbol when doing the electrical tests at the start of the thread. Matt has an OBD reader that he used to clear it. Max said his stopped flashing on its own eventually. They both had faulty pressure sensors (note that I'm not implying that your pressure sensor is faulty Jay)

Patch lead to measure in situ will be very interesting !!! :)

.
 
Hi Brian,

RE. The flashing glow plug symbol, it only started flashing the moment I started the car up after they sucked the refrigerant out. I had done those tests on the pressure switch the day or so before that, with no flashing light. Hmmm the only other thing I did at the same time as having the refrigerant sucked out was to remove the clutch relay so that I don't accidentally start the aircon pump up dry.

I am waiting for an OBD reader to be delivered that I ordered the other day (bluetooth to android using a program called Torque hopefully) so will see what that light means then.

I want to do the patch lead before getting her recharged just in case I was getting dodgy readings. This may also give me some useful comparisons.

Can't think of a better way to spend a Friday evening....cough
 
I think they both had the same fault code " P0645 - ac clutch relay error"
You need an OBD reader that can clear codes too.

If you work on the car this evening you'll miss the Olympics opening ceremony .... it's going to be a real sacrifice to miss that LOL :)
 
Nearly there.
When I got home I got straight to it.
1) Poly belt off with my newly made extended 14mm spanner.
2) Alternator out
3) Condenser fan out
4) Air con pump out
Fitting is the reverse
All covered elsewhere so no point in clogging the DIY with repeat pics unless anyone wants specifics.

The good news is the old pump does not actually pump at all. In fact I can't see anything moving inside when I look through the port. Something has obviously disconnected inside. I would say that is a hell of a result. I will be taking this sucker appart and will take pics if your interested.

My OBD2 bluetooth reader came today. Very good. Linked up to phone and it mimics everything including things like throttle opening positions and other things that are of no interest to me lol. You can even use GPS instead of the car data to get real speed. Anyhow It had 4 faults. I think 3 were previous ones like low fuel rail pressure or something. (that was when i accelerated to about 4000rpm while going onto a slip way and the engine came up into limp mode). I read this forum and deduced it was fuel filter. Did that the other day so sorted. And no I don't drive like an idiot....any more. Getting old you see so no need to rush any more lol. Back to the final fault: yep the ac clutch relay error. I reset all codes and it just leaves this one displayed. I'm guessing it's due to either low pressure or more logically the clutch relay being removed. I brought some of my wireing bits home so will make this patch lead and test the 3 wire pressure switch. Depending on the results I will then go get the air con charged up.

What Olympics opening ceremony? No one told me, damn. Does anyone have a copy of it? never mind lol
 
I connected the patch lead to the sensor only and got similar results to my previous readings.

Resistance
Again if you look at sensor and number the pins from top to bottom as 1, 2, 3 (***uming the plastic release clip on the sensor is facing the front of the car) I had readings of
1-2 = 11.37kΩ
2-3 = 4.7kΩ
1-3 = 6.65kΩ
I then connected the other end of the patch lead to the plug so that this patch lead is series with the normal circuit.
At this point I would not recommend using a DVM for reading resistance not only because the readings will be useless as you would now be trying to measure some of the cars electronics but you may (very unlikely) damage any sensitive circuitry. I would only measure DC voltage when connected up with a patch lead.

Voltage
The only reading I had between pins was between pins 2-3 which was 4.5v with 3 being the +ve
Between 2 and 0v (car body) was +.5v.
Between 3 and 0v (car body) was +5v
So pin 2 carries +.5v and pin 3 carries +5v which explains the pd between pins 2 & 3 being 4.5v.
I will take more readings with the system pressurised soon.

Here is the patch lead I made. Not pretty but functional.
Patchlead.jpg



I decided to go get the system charged yesterday and brrrrrrr it now WORKS Yipeeee

Icecrystals.jpg

Random...almost. Ice on my fishing brolly in Dec 2011

Left to do;
1) Measure the voltages and resistances of the pressure switch now the system is charged and working (be interesting to see if the voltage varies as the pump cycles).
2) Strip old pump to see what’s occurring.
3) Keep my gloves and Beanie in the car lol

Finally a big thank you to you forum guys especially Brian for the help on this.

Jay
 
Jay that is awesome work !!!

You've saved yourself about £1000 by not getting it done at a dealer (no joke, that's how much it would have cost). Not only that, you've discovered that the pressure sensor on the diesel car is not a switch like the sensor on the petrol car, but probably acts like a potentiometer (or maybe an active device) that presumably gives a voltage proportional to pressure (though I would expect pin 1 to be 0V)

btw did you take the compressor out from above, not from below ?
.
 
Yep took alternator out then aircon fan and finally compressor out, all from above.

I only popped in to see if anyone replied lol. I'm working on a friends Vectra at the moment. he said it was rattling. The idiot who changed his cambelt had split the cambelt cover and bodged it with fibreglass tape or something and used lots of washers to pack the cover screws out. Also notice the cam belt tensioner was beyond minimum. You could press the belt between the cam pulleys with your thumb and see the belt teeth riding up. I have no clue how he managed 1000+ miles without throwing the cam out.
 
Hi Brian,

I had a look under the hood and don't think it is possible to remove the compressor from below unless you lower the sub frame or maybe slide it out the inner wheel arch. Since you have to remove the auxiliary belt to get the compressor out, it is only 10 minutes work to pull the alternator out so much simpler to work from above.

I think you may be right about the switch and I too was expecting pin 1 to be 0v. Maybe because I had the clutch relay out and had that fault code as well as not turning the air con on (while the system had no pressure) was causing no connection to pin 1. I will confirm it this week by reinserting the patch lead.

I will still do those final checks and tests before I can sleep properly lol.
 
luvmyaccord said:
Brian that's a seriously well written and in depth how to. Well done mate. Rep point coming your way!!!!
Click to expand...
Great thread and exactly what I'm looking for.

I have a 2006 Accord 2.2 i-ctdi and have had an inoperable air con system for the best part of the year.

However, where my issue varies, I do get cooler air through the vents when a/c is switched on, but the volume of air or the blast doesn't alter at all.

The system has been recently gassed and the pressure switches have been checked this morning, but when the air con engineer ran a diagnostic check (Honda approved) it just showed "fault" with no further instructions. He said best bet would be to take it to a Honda service centre with a better diagnostics setup than his, but I was wondering if anyone had any similar issues?

Blower motor etc is fine and pollen filters regularly changed.

Many thanks in advance.

By the way, I'm ***** with cars!
 
Hi Mark and welcome to the forum.

Does your car have the Nav or is it the other consol?


My car has the sat nav built in which does have a sort of basic diagnostics screen, or more to the point a map of various items that I guess go through the nav panel control. Ant, GPS, navi ECU, Audio, disp and more importantly in this scenario is Aircon. All these items are green when healthy. However even my original fault of the compressor not compressing didn't change the Aircon icon from green. The only time I saw it go red was when I had no gas and the compressor clutch relay was removed, this could be an either/or as I didn't follow this path to conclude which caused the fault indication. The other thing to note is when I did get the system evacuated of gas I had the engine management fault light on the dash come on. Once re-gassed I had to plug my OBD reader in to reset it..


You say you get 'cooler air'. Are you sure you are not just feeling the moving air and you are experiencing a chill factor? I did in the early days. Do the pipes under the bonnet get cold? (like chilled cold). Does the compressor clutch actually engage?

Jay

All, I still have some unfinished business on this subject (namely to reply with my final findings from before). All is still working with my car. Today is cracked manifold replacement day for me wooohooo oh joy.
 
hello
can you help me !
2007 diesel 2.2 ictdi
aircon problem:
when i turn on my AC PESSENGER SIDE proper cold come out ,but driver side is not too cold!!what could be the problem ???why?
 
Wow this is a fantastic thread!! I think my compressor is kaput so thinking of sourcing a replacement and swapping mine out...do you need to fill up the oil or something when you put in the compressor? If so what type of oil and how much?
 
this weekend I tried switching on the ac after about 4 months and no cold air came out :/ will first check hopefully only needs to be topped up :/
 
this picture is of the pulleys in the petrol, but diesel is similar.

You can just see the compressor pulley right at the bottom.

With engine running all pulleys rotate, but with aircon off there is a "rotor" inboard of the compressor pulley which is stationary.
When aircon is turned on, that rotor should rotate, and you should be able to hear the low-pitch "groan" of the compressor.

Lift the bonnet of the car, get someone to sit in the car, then with the engine running get them to turn the aircon on and off. You should be able to see and hear the compressor rotating when aircon is on.

If you can see and hear the compressor, then get the pressure tested. If the pressure is ok, then on the diesel, it's either the valve or the switch that are both located down in front of the condenser, you can see them by looking through the lower grille of the bumper.



DSCF0525.jpg
 
Have just posted a note on the other air con problem thread that relates to testing diesel air con pressure switch, and resistance readings when switch is bad and what are they when new?
Answer is "the same"
I now have a dismenbered bad one, a bad one and a new one from honda fitted, regassed and it all now works
 
Mine's stopped working. Took it down to Kwik-Fit for a gas, which they did, it made no difference so they didn't charge. The lad said pressure is fine, compressor is kicking in so it needs further investigation. Don't really want to go to Honda and spend ££££'s. not sure what to do next?
 
***uming that Kwik-Fit are corect i.e. the gas pressure is correct and ***uming that the compressor is kicking in

then, probably a badly perished condenser

to test for badly perished condenser
set the temperature to LO (next click down from 16)
go into the A/C menu, set A/C to ON, put the direction to --> , put the fan speed to about 4

go for a drive in the car at a steady 60 or 70 mph for several miles and you should start to feel cold air coming in


if no success, then remove the pollen filter and try again (now clutching at straws).

if still no success, then you have a problem in the controls behind the dash, could either be the temp sensors, or the motors on the flaps, or the controller itself. Try experimenting with the direction settings and listen to the flaps moving, and try dual on and dual off and try different temp settings.

All of the gubbins behind the dash is here in this URL
http://www.lingshondaparts.com/honda_car_parts_selection.php?block_01=17SEA01&block_02=B__1721&block_03=2768

To get behind the dash will take a lot of time, getting someone else to do it will take a of money


external sensors are in this URL

http://www.lingshondaparts.com/honda_car_parts_selection.php?block_01=17SEA01&block_02=B__6100&block_03=2768
 
Just to clarify; I do have air blowing in, all the settings are working its just not cold! If I leave it on auto and a low temp then the recirc button is always lit. Warming things up is the complete opposite, that's working great!
 
When driving down the Mway for several miles how cold should I start feeling the air? air con cold or just colder than it has been?
 
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