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Diagnosing Aircon Problems

Hey Brian, excellent topic! :)

I'm in need of your expertise....

2.0 petrol, getting slightly cool air, but nowhere near to proper A/C temps.

Can hear the clutch engaged either using the A/C button, or using a wire from the +ve terminal. with the engine running and A/C set to Lo, I don't think it turns off... at least not as regularly as it used to.

I have the self recharge kit and decided to check out the pressure. With the compressor running, the pressure was around 5psi (way below 'normal') so I put about half of the can into the system. The pressure rose, but then struggled to get up above approx 15 psi... I'm presuming this means I have a leak somewhere, but the weird thing is with the engine off, the pressure on the low side jumps round to about 40 psi ?

Is this normal?

Does it sound like I need a new compressor?

I have also recently had the bumper off and noticed that the condensor is the worse for wear.. If I'm driving at motorway speeds, it does get cooler, so it will most likely need replaced too.

Cheers,
Matt.
 
My expertise doesn't go as far as the pressures :mellow:

AFAIK the systems are normally filled by weight (mass) of gas and lubricating oil. To do that, the system is fully evacuated (which helps check for leaks) and then the correct quantity of oil and gas is put into the system.

I does sound as if the perished condenser is part, or all, of the problem. I bought my condenser from Unipart , a nearby Halfords Autocentre (different from a Halfords store) evacuated the system, then I went back to my house, removed the front bumper, took out the old condenser, put in the new condenser, put back the bumper, and went back to the Halfords Autocentre.

Cost me £150 in total.
 
No worries, I'll source a condensor first and see if that helps...

Will report back in a while.. :)

thanks!
 
Hi Brian,

I never got around to replying to your post last August :blush: , just to let you know your suggestion worked perfect in diagnosing the fault, I connected the cable from ac relay to battery positive and I could hear clutch engage, I then connected cable to 2 connections on ac relay and could hear clutch engage so this pointed to the ac relay as fault. I then purchased a new ac relay Honda Part No. 39794-SDA-A05 for a grand sum of €37 delivered and the system is working perfectly and still is in this hotish weather.

Many thanks for your help.
Tom
 
mattster said:
No worries, I'll source a condensor first and see if that helps...

Will report back in a while.. :)

thanks!
Click to expand...
ok, don't buy OEM, it isn't required, the one from Unipart on my car is still perfect after nearly 5 years

AccordDub said:
Hi Brian,

I never got around to replying to your post last August :blush: , just to let you know your suggestion worked perfect in diagnosing the fault, I connected the cable from ac relay to battery positive and I could hear clutch engage, I then connected cable to 2 connections on ac relay and could hear clutch engage so this pointed to the ac relay as fault. I then purchased a new ac relay Honda Part No. 39794-SDA-A05 for a grand sum of €37 delivered and the system is working perfectly and still is in this hotish weather.

Many thanks for your help.
Tom
Click to expand...
glad I save you the hassle of replacing the compressor ;)
 
Need some help if possible tried everything in this post and still no joy stuck on ideas on what to do now
 
simpo said:
Need some help if possible tried everything in this post and still no joy stuck on ideas on what to do now
Click to expand...
I've had a look at some of your previous posts and seen that your car is CL9 (2.4 saloon)

This is important, because when I started this thread in May 2012 I was not aware of the big differences between the aircon system in the 2.4/2.0 petrol cars, and the aircon system in the 2.2 diesel car.

The system in the petrol cars is a much simpler system, and it is fairly easy to comprehensively troubleshoot.

However the first part of troubleshooting is the same on both systems, which is to check the state of the compressor. There are two things we can check
1. if the electric clutch is working
2. if the compressor is internally compressing (and/or enough gas).

To do the first check, you do not need the key in the ignition. Simply remove the compressor clutch relay (as shown in the pictures in #1 of this thread) and connect a wire from pin 2 of the empty relay socket to the battery positive, and you should hear a "clunk" from the compressor clutch.

If you do hear a "clunk", remove the wire, leave the relay out, and do the second check. Start the engine, set the target temperatures to LO, go to manual control of the A/C, set A/C ON, blowers to max, then connect pin 2 in the relay socket to battery positive, and feel if cold air is blowing. DO NOT LEAVE IT LIKE THIS FOR MORE THAN A MINUTE. If you can feel cold air blowing, then there is a fault elsewhere (come back and we'll go to the next stage, which is easy on the petrol cars). Otherwise, the compressor is not compressing (faulty), or no gas in the system.


This picture shows the pin numbers on the relay


relay_pinout.jpg
 
Ok I'll give it a go today def has enough gas as I had it refilled the other day lol
 
I would like to credit this thread with saving me a fortune. I changed the pressure sensor on the 2.2 cdti (80450-s7s-003) today. Worked a treat after trying the tests on this thread. Thanks
 
hollow said:
I would like to credit this thread with saving me a fortune. I changed the pressure sensor on the 2.2 cdti (80450-s7s-003) today. Worked a treat after trying the tests on this thread. Thanks
Click to expand...
glad it helped, quite a few people with the 7th gen diesel have found that, having checked the condenser (as in #127), it's the pressure sensor stopping the controller from bringing the compressor in - and the sensor is cheaper and easier to fit than a replacement condenser
 
mattster said:
No worries, I'll source a condensor first and see if that helps...

Will report back in a while.. :)

thanks!
Click to expand...
Ok, it's only taken 2 months, but my air con is finally working again!

Got a new condensor off ebay from a French seller - roughly £65 delivered which seemed good... took me about 6 weeks to get around to actually fitting it, which was a simple enough affair to be honest. Hardest bit is getting the front bumper off, but once you've done it a few times and have a ready supply of trim clips it's easy..

I made the mistake of replacing the condensor o-rings with the ones that were supplied with the unit. :angry: They turned out to be a fraction too small, so on attaching the A/C recharge unit, a major leak was reported..

A new pack of AC O-rings and an hour later they were both changed for the proper size. Taken back to Halfords for the recharge this weekend and everything is frosty once more. Not a moment too soon either, as I'm due to drive 800 miles to meet a mate for a curry and a beer next weekend.... :blink:
 
Hi guys.....some help from the hive mind please ....air conditioning stopped working....tech regassed and said poor relay connection at fault.... now cold as ice on low settings....but I'm not happy that it's kicking in when I turn down the temp on the climate control dial....and thoughts?
 
You can look at various temperature sensors (and other things) by using the built-in diagnostic
(click on the image to enlarge)
SEA3E50K71100000000BBAT00_4.jpg



The only "difficulty" ergonomically speaking is that, when in diagnostic mode, you can't see the "target" temperatures in the upper display. This is because the upper display shows the value from the selected sensor instead.

Best thing is to practice "blind" setting the target temperatures when in normal mode i.e. start with the target in LO then count how many presses of the red "up arrow" it takes to get to HI, so that you can set any desired target temperature "blind" by counting the up/down presses from LO.

Then set the target temperature to LO, switch off the engine, follow the instruction in the image above, then set the temperature by counting the presses of the "up arrow".

You can drive the car while the system is in diagnostic mode and look at any sensor.

In particular, look at the temperature sensor readings (sensors 1, 2, 4, 5) and see if they are "reasonable". Sensor 4 (engine temperature) should reach about 80 C. Sensor 5 (evaporator temperature) should be about 5 C with the aircon ON. With aircon OFF it should settle at ambient.

For "sensors" 6 and 7, as you change the "target temperature" (blind) you should see the flap % change. This is important because the flap % indicates the mix of hot and cold air that the controller is trying to achieve.

Sensor 9 is strange, I think it is "virtual", and is a function of "target temperature" minus "in-car temperature

Note that on the diesel car, there is also a 10th sensor, which is the pressure out of the compressor in Bar. It should be between 10 and 15 with aircon ON, and about 6 with aircon OFF.
 
freddofrog said:
You can look at various temperature sensors (and other things) by using the built-in diagnostic
(click on the image to enlarge)
SEA3E50K71100000000BBAT00_4.jpg



The only "difficulty" ergonomically speaking is that, when in diagnostic mode, you can't see the "target" temperatures in the upper display. This is because the upper display shows the value from the selected sensor instead.

Best thing is to practice "blind" setting the target temperatures when in normal mode i.e. start with the target in LO then count how many presses of the red "up arrow" it takes to get to HI, so that you can set any desired target temperature "blind" by counting the up/down presses from LO.

Then set the target temperature to LO, switch off the engine, follow the instruction in the image above, then set the temperature by counting the presses of the "up arrow".

You can drive the car while the system is in diagnostic mode and look at any sensor.

In particular, look at the temperature sensor readings (sensors 1, 2, 4, 5) and see if they are "reasonable". Sensor 4 (engine temperature) should reach about 80 C. Sensor 5 (evaporator temperature) should be about 5 C with the aircon ON. With aircon OFF it should settle at ambient.

For "sensors" 6 and 7, as you change the "target temperature" (blind) you should see the flap % change. This is important because the flap % indicates the mix of hot and cold air that the controller is trying to achieve.

Sensor 9 is strange, I think it is "virtual", and is a function of "target temperature" minus "in-car temperature

Note that on the diesel car, there is also a 10th sensor, which is the pressure out of the compressor in Bar. It should be between 10 and 15 with aircon ON, and about 6 with aircon OFF.
Click to expand...
Thank you.....a job for the weekend me thinks

Sent from my ONEPLUS A3003 using Tapatalk
 
Just thinking....are there any optimum numbers for these settings.....what would you suggest as reasonable for 1,2,4 and 5 please?

Sent from my ONEPLUS A3003 using Tapatalk
 
well at the moment it's about 22 and overcast/sunny in Maidstone --> http://www.bbc.co.uk/weather/2643179 and on that basis

sensor 1 = 22 if parked in a garage , 25-ish if driving with windows open, or 35-ish if parked outside facing south with windows shut
sensor 2 = 22
sensor 3 = 00 if parked in a garage, 30 to 65 if outside
sensor 4 = 22 if engine cold, or 80 if fully warmed up
sensor 5 = 22 if engine cold and aircon OFF, or 5 if driving with aircon ON
 
Ok readings 1 - 27, 2- 21, 3 - 72, 4 - 80, 5 - 03, 6 - c9, 7 -1, 8 - 0, 9 - A2, 10 - 15.... seemed to be working ok on way back home today

Sent from my ONEPLUS A3003 using Tapatalk
 
Although definitely not 27' in car? Could be an issue with sensor 1.

Sent from my ONEPLUS A3003 using Tapatalk
 
What temperature do you think it was in the car ? If it was out by about 5C I wouldn't be too concerned but maybe keep checking it.
 
Probably around 22' the air conditioning had been on for 30mins

Sent from my ONEPLUS A3003 using Tapatalk
 
Sorry these readings were taken on my drive when home....will check again tomorrow

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Hi All, Very well written and explained. However, I overlooked something when I began my checks and now have a problem which I don't know is related or not. I have a diesel version.

I did the first two checks with the compressor clutch relay and each test produced a clunk. I then went onto the third test which was to swap that relay with the cooling fan relay. Before starting the engine to run it up to temperature I removed what I thought was the cooling fan relay to inspect it because it looked smaller than the one on the photo and realized it was a blank in the diesel. So I put it back. And I replaced the compressor clutch relay.

I then started the engine and have a flashing glow plug indicator light and the engine malfunction lamp is on. The handbook talks about dire consequences of driving it. I've restarted it three times as the book says but they are still on. Any ideas?

Thanks
Bob
 
When I started the thread 5 years ago (almost to the day) I didn't know that the aircon in the diesel is radically different from that in the petrol car.

However a few days later Matt (mattlee) and Max (Max10) , who both had diesel cars, had found that the pressure sensor in the diesel is an '****og' pressure sensor not a pressure switch (which is in the aircon in the petrol cars) ....see #17 on the 1st page.

Not only that, but the compressor relay is turned on and off by the ECM (engine ECU) and although this is true for both cars, for some reason the ECM on the diesel knows if the relay coil(s) are open circuit (removal of the relay will simulate open circuit).

Hence the diesel engine throws up a DTC P0645 (which does not exist on the petrol engine car) which brings on the glow plug warning light (because there is also a relay for the glow plugs).

see --> http://typeaccord.co.uk/forum/topic/10382-diagnosing-aircon-problems/?p=117296
 
Thanks Brian. That will teach me. I should have read more of that thread! I guess no harm's been done then - it certainly drives fine. Now I've just got to figure out how to reset it.
Thanks again for taking the time to reply to someone who should have continued reading.
Bob
 
You're probably not the first and won't be the last , the opening post really needs a re-write, because the compressor clutch engagement test (with relay removed) can be done without the key in the ignition ;)

The quickest way to get rid of the warning light is to get a code reader. If you have an Android phone search for "ELM327 Bluetooth" (without quotes) on ebay , or "ELM327 WiFi" if you have an Apple phone. Best to use "advanced search" and select "Buy It Now" and select "Located In United Kingdom". They cost under £5 . You'll also need an app for the phone. This will be able to read and clear all engine codes on any car made after ~2002.
 
Great job freddofrog....I know from experience how relieved Bob will be by your rapid response.

Sent from my ONEPLUS A3003 using Tapatalk
 
My aircon seems to work ok again....I am wondering if the relay which had a bad connection may be weak....may replace it any way....but for now the system has been regassed too and is nice and cool ❄️

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If it seems to stop working, check all the sensors again, it could be the relay, or it could be the in-car temperature sensor has gone too far out of spec.
 
Ok buddy will run a check again on the numbers thanks

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