Air Cconditioning Self Diagnostic

[Mooly]

I wouldn't worry too much yet... you will probably find it's colder when the outside air is warmer. I remember when I got the TSport, I was concerned the AC wasn't ice cold... but it was fine.

If you lift the bonnet with the AC on can you see the two pipes that disappear into the bulkhead. One of those should be cold and wet through with condensation if it's working OK. Actually I've never looked under an Avensis bonnet but I'm guessing it's the same as 99% of other vehicles.

If you put the system on "max cold" the temperature at the vents should be around 5 to 8 or 9 degrees at a guess.

[Rossi46]

Myko

your system has a leak, 00 means the sensors are ok and the pressure in the system is enough to engage the compressor. from memory 21 is the low system pressure one. my original post was asking how to do the test as i couldnt remember.

the codes are not obd standard obd2 codes, they are specific a/c ones.

i think the original info was from a manual but i can't remember where.

good luck getting it sorted.

[Myko]

Brilliant, thanks very much Rossi, I appreciate the reply. Will get it booked in with Mr T again...

[Mooly]

Brilliant, thanks very much Rossi, I appreciate the reply. Will get it booked in with Mr T again...

Is it failing again though, in the short time since you had it serviced ? or are you just worrying about the codes ?

Keep us informed :)

[Myko]

It does not seem as cold as my company fiesta, although its a lot bigger inside so more warm air to cool down, I cant tell as its cool just not as cold as i'm used too! I'm worried if its a leak or a compressor problem that Mr T (if left) will tell me it needs a refill or service again and not actually replace the faulty unit. I thought if the unit is bringing up codes then surely they must mean something to someone and not as toyota say, useless!

[Mooly]

The only way to say for sure if it's leaking... well two ways... is first a visual inspection as you now have UV dye in the system. That shows up clearly under UV light. And second to recover the gas and weigh it and compare against what was put in.

Now Toyota I'm pretty sure are not going to do that if the system seems OK and the vent temperature is normal. Not for free anyway.

I wouldn't like to comment on the codes... most consumer gear from TV's to PC's etc etc has various service modes that can be accesed by unique sequencies of button pressing... and unless you know what you are doing it's asking for trouble to play around with these. It could be anything from "just codes" indicating something, to setting various options for different models etc... unless you have all the service info you just don't know. I've no connection with the motor trade at all by the way... I'm an electronic electronic engineer by profession.

By all means ask... but if it all works normally I wouldn't worry to much.

[Thermal]

Not sure if these match your A/C model, but I found this information re the fault codes:

00 - no errors found

11 - Interior temperature sensor

12 - Exterior temp sensor

13 - Evaporator temp sensor

21 - Sunlight sensor

23 - Refrigerant pressure sensor

24 - Sunlight sensor (another one?)

31 - Air mixer valve motor potmeter, passenger side

33 - Airflow motor potmeter

36 - Air mixer valve motor potmeter, driver's side

*added later*

41 - Air mixer valve motor, passenger side

43 - Airflow motor

46 - Air mixer valve motor, driver's side

Notes:

Translated from German into English, so the wording may not be entirely correct, but you'll get the general idea.

( F.i. try to correctly translate "Mischluftklappenmotorpotentiometer" into anything :D )

Also, passenger and driver's side may have to be reversed for UK cars, and don't ask where all these sensors are...

Use for info only.

[Myko]

Thats great stuff thank you Thermal and everyone for all your help and information. I now have something to go on when I see Mr T although if the codes are correct then i'm no longer worried. Was worried about the compressor but if its only sensors then sure thats nothing major.

P.S. How many sensors does a AC unit need! lol

[Thermal]

...How many sensors does a AC unit need

Yeh, the car's A/C, or better, Automatic Climate Control System, is a highly complicated piece of equipment.

First off, I don't know exactly what the test procedure should be, but IMHO the procedure described here is incomplete and does not describe what codes to expect and when to expect them.

It only describes which buttons to press to start a test sequence.

For instance, the sunlight sensors on the dash must be covered when the test is started, otherwise you may get false error codes 21 and 24.

That's why the outcome of the test is different when done in a dark garage, or outside in bright sunlight.

The procedure does not say if the ignition must be on or off, and whether the engine should be running or not.

etc. etc.

Also be carefull with pressing any buttons in the car while the A/C "test" is running.

You might change vital settings without ever knowing.

[Mooly]

The important sensors relating to the AC are pressure switches on the "low" and "high" sides of the compressor.

Insufficient gas causes the low pressure switch to remain cut off to protect the compressor... which musn't run under those conditions as it needs the gas (and hence oil) to circulate for lubrication. The high pressure switch protects from excessive pressures in the event of a fault etc... such as the fan on the condensor at the front not working.

[Rossi46]

These are the codes and diag info which I was looking for.

I had a CD which I only found yesterday.

aircon diag1.pdf

aircon codes.pdf

code 21.pdf

code 24.pdf

code 41.pdf

aircon locats.pdf

I only re-visited the post as I currently have a problem, giving me as low as 3 degrees C on the RH vents (up to 60 degrees C)and a steady fixed 60 degrees C on the left.

The codes 21 and 24 are red herrings I believe, as it's unlikely both sensors are U/S.

My problem is the mixer servo, so I need to get stuck in.

The 2 buttons I suggested in the earlier posts are the the correct ones (auto and recirc), they're just in a different position in the LHD model seemingly.

Hopefully these codes and info will be of some use.

[roswellgrey]

Hopefully these codes and info will be of some use.

Old post I know, but I would like to say thanks for the info contained within this thread.

I had a aircon pipe rust through, and obviously all the refrigerant leaked out.

After a "it must be the compressor" chat with one place, I found this info and

the aircon diagnostics showed low pressure cct ( code 23 ).

Leaky Pipe found under presure test, replaced and system regassed, and it back to

showing "00" and working correctly - phew :)

Obviously the concerns stated above about pressing buttons during the diagnostic mode are rather valid - its possible

that you could reconfigure all sorts of things in a bad way, but this is an extremely useful diagnostic

(if used carefully) to see if the ac system is at least trying to energise the compressor (without getting the multimeter out)

Thanks again.

[Rossi46]

Hopefully these codes and info will be of some use.

Old post I know, but I would like to say thanks for the info contained within this thread.

I had a aircon pipe rust through, and obviously all the refrigerant leaked out.

After a "it must be the compressor" chat with one place, I found this info and

the aircon diagnostics showed low pressure cct ( code 23 ).

Leaky Pipe found under presure test, replaced and system regassed, and it back to

showing "00" and working correctly - phew :)

Obviously the concerns stated above about pressing buttons during the diagnostic mode are rather valid - its possible

that you could reconfigure all sorts of things in a bad way, but this is an extremely useful diagnostic

(if used carefully) to see if the ac system is at least trying to energise the compressor (without getting the multimeter out)

Thanks again.

You're welcome, i'm glad it helped you.

[Flackadder]

I have slighty colder air from left vent as well. Have to go see Mr T soon anyhows, to get that fuel line recall thingy checked out.

[Barnman]

Hi Guys, found this posting while searching the forum for Climate Control problem....

My 08 Avensis has the usual dual climate control. It was working fine until last year (Spring 2011) when it would not blow cold.

Air Con Diagnostics mode showed "00" i.e. no fault code.....

Local Toyota dealer simply said it needed re-gassing. This was done and it blew cold for only a few weeks.

Back and forth for new flap valve to be fitted etc. Then they said it needed a new 'heater box' !!

This was done under the Toyota 3 year warranty. It worked fine all of Summer 2011.

Jump forward to Spring this year (2012) and it has started with the same problem all over again.

It is booked in to the Toyota garage to 'have a look at it' on Monday....

What was the problem with your Avensis and how was it fixed?

[bobbik1]

Thanks to pdf's @Rossi46