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IQ 2 1.0 - Climate Control Not Working

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I have an IQ 2 1.0 2009 model - the digital climate control isn't working.

Had the system re-gassed and pressure tested recently as the car is a 3rd car in the house and wasn't used since lockdown - the compressor isn't kicking-in for some bizarre reason.

It was main dealer serviced on 13/03/2020 (just before lockdown) - but a main agent service doesn't cover the air con as it had packed up a few days prior.

I've read the other forums about this - but I am confused including the detailed one by hotwiring the relay and using the Toyota EOBD software for diagnostics - i have in fact ordered that kit for my old Windows XP laptop - should be here in 1 week (cable and V14 of the software).

To recap, there are the following components used: Compressor, Magnetic Clutch and Relay.  The cost for each is £450, £328 and £75 respectively.  Mega bucks and with Dealer Stealer fitting of clutch and compressor, I am looking at a bill of £950 (supply and fit).

When speaking to a few main agents, they are mesmerised why the air con has failed - in their opinion it's a robust unit. Is this correct?

Therefore, do I fit a new Relay (or do the hotwire) or shall I plug in my forthcoming Toyota V14 software with Mini VCI Car OBD cable and see what the voltages say?

Advice needed please.



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There is a Technical service bulletin for a known potential issue with a Faulty compressor that could affect a 2009 IQ


Subject: No aircon operation due to compressor failure

Models: IQ

Model codes: KGJ10, NGJ10, NUJ10

DESCRIPTION OF PHENOMENON: The customer may complain that the aircon system is not cooling.

PRODUCTION CHANGE: The shape of the 'refrigerant fluid sensor' changed to avoid blocking.

REPAIR PROCEDURE: Please replace the defective compressor with a new, modified part.



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Quick update...  I purchased a brand new Denso compressor with brand new magnetic clutch - its on it's way by courier. I also get a 2 year Denso warranty.

Are there any suggestions on how to best fit this?  Apparently the DENSO compressor will be pre-oiled etc... with magnetic clutch pre-assembled but I want to make sure my local garage (reputable may I hasten to add and better than Mr T's £130 per hour!!!) fit it properly and carry out whatever is necessary.  It's an expensive piece of kit, but I got a snip compared to main agent prices.

Do people recommend changing the belt at the same time?  What about snap ring or any other bits?  Just want a few tips of what needs to get done - during and after the compressor fitment as I don't imagine I will be changing that again in my ownership!


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Would this not be better entrusted to an air con specialist rather than a normal garage? Your garage may well  get a 3rd party to do the work in any case... have you asked? It is very specialised work, the exact amount of the correct and very special Oil has to be used for your system and that Oil is hygroscopic to the point that once a container has been opened to the air for even a couple of hours it should be discarded. The moisture turns the Oil acidic which is something you do not want to happen.

Use a specialist would be my advice... or use MrT who will either have someone trained up or will use an approved company to do the work.


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Hi Mooly,

Thanks for your response. Please don't get me wrong; they are a reputable garage who deal with Air Con systems - I opted into getting a proper Denso unit myself.  

My question was more about what people would do whilst having the compressor changed. My belt appears to be ok (Mr T healthcheck on 13/03/2020 was all green) - but for a sake of £15, I may get it changed anyway to last me a while.

Just like changing the waterpump when doing a cambelt; what other things do people do when changing the compressor - that was my question?

I look forward to your response.

Thanks again!

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Its not so much what people do, its more a case of what should be done to get the system back to original condition. The compressor contains a certain amount of Oil suitable for the system it is installed into, lets say 120 millilitres of Oil. Most of that stops in the compressor but some will circulate and remain in the other parts of the system... which is an unknown. So ideally the old compressor is drained of its oil and that is then measured (lets say you get 100cc out of it) and then a similar amount (so 100 ml) of fresh Oil added.

If the system is totally flushed and cleaned of old Oil first (which your A/C guy may well do) then you add the full recommended amount of fresh Oil to the compressor (so 120ml) as you are starting from a known 'clean' condition.

When pumping down to a vacuum and refilling with refrigerant the system should be pumped down for a more extended period of time to absolutely ensure all moisture is removed.

It's all bread and butter stuff to a proper A/C technician which is why should use one. A garage that just does basic preventative maintenance and regassing/servicing of already working systems may not be the best option. If they are a proper A/C repair centre then you have to trust them.

Good luck and let us know how it all works out 🙂





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@Mooly You seem to have some knowledge of aircon systems and I'm wondering if you might be able to help. 

About a week after mine was regassed a month ago (due to the system not generating cool air), I've noticed water leaking into the driver's footwell (from the 'tunnel' just to the left of the clutch pedal). Not sure if the two are directly linked or not. Do you think the water leak is somehow related to the regass? And if so, where could it be coming from? I've extended the condensate pipe in case water was wicking back through the bulkhead, but that hasn't helped. 


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I can't see how anything related to a regass would cause would cause water in the footwell tbh. A regass only involves connecting a couple of hoses to the service valves under the bonnet, like connecting a tyre to an inflator. Nothing gets disturbed doing this.

If it were moisture from the evaporator (the bit that gets cold under the dash) then it would have been doing this before, at a time when it was all working.

Water can travel a long long way via capillary action and end up visible miles away from the source of the problem. Even a leak at the top of the windscreen could do this.

Easiest way to 'prove' it is just to not use the A/C for a few days and see what happens. With a rainy spell imminent it would be a good test. 



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Thanks Mooly


I can't see how anything related to a regass would cause would cause water in the footwell tbh. A regass only involves connecting a couple of hoses to the service valves under the bonnet, like connecting a tyre to an inflator. Nothing gets disturbed doing this.

That's what I thought in regard to a regass.

I am currently investigating. Aircon has been off for a few days and the carpet is drying out.

Rain is forecast tonight; another test 😉

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  • 3 weeks later...

Compressor installed and re-gassed the whole system - the published time is 3.2hrs to do the work replacing the air con compressor, but the garage I used did it in 1hr and re-gas on a Sun system using R134a gas (it's an 09 car) took around 30 mins.  I have cold air and i am happy!

Thanks for your help.

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