- Thread starter dobbslc
- Start date
You need to know how much pressure is in the system for a start, because "some" might not be enough.
First port of call is always going to be getting a good code reader on it and seeing what the ECU's are actually seeing. Without that I'd think your on a hiding to nowhere.
First port of call is always going to be getting a good code reader on it and seeing what the ECU's are actually seeing. Without that I'd think your on a hiding to nowhere.
Check resistance across the coil of the magnetic clutch. It shouldn't be a lot but if it's tens of ohms, check for high resistance at the earth connection. Also check for voltage at the coil when the AC says it's on.
If there's voltage at the coil but the clutch isn't engaging, check the gap between the pulley and the flexture plate with a feeler gauge. The flexture plate is shimmed and you can adjust the shim stack to take up any wear and make the clutch engage again.
If there's no voltage at the coil connector, check the relay. If the relay is good, but no signal voltage to the relay, it might then be pressure related. There may also be a thermal cutout that may or not be resettable.
What car is it?
If there's voltage at the coil but the clutch isn't engaging, check the gap between the pulley and the flexture plate with a feeler gauge. The flexture plate is shimmed and you can adjust the shim stack to take up any wear and make the clutch engage again.
If there's no voltage at the coil connector, check the relay. If the relay is good, but no signal voltage to the relay, it might then be pressure related. There may also be a thermal cutout that may or not be resettable.
What car is it?
Ubique
Member
- Messages
- 2,700
- Location
- East Midlands
System pressure is the first check as mentioned above, what comes next is entirely dependent upon that. Bear in mind that the pressure is temperature dependent, on a system at 20deg.C. Ambient and static (compressor not running) using R134 refrigerant you should see around 4-6 Bar, anything less than 3 and the pressure sensor or switch will be preventing system operation. If you're getting pressure in the correct range, then diagnostic code read is the next step, if it has a sensor rather than switch, read the live value to check for correct operation.
dobbslc
Member
- Messages
- 14,168
- Location
- Hertfordshire UK
I have a Topdon Artidiag 500 but having just looked at the specs on it I'm not sure it covers AC.
It's a Mazda 3 2015 skyactive.
dobbslc
Member
- Messages
- 14,168
- Location
- Hertfordshire UK
A friend has a set of gauges I can borrow so I'll tap him up and check the pressures. Thanks.
Ubique
Member
- Messages
- 2,700
- Location
- East Midlands
In a workshop environment, a pure pressure check isn't reliable as it doesn't really indicate how much refrigerant is in the system. Ideally you'd recover the refrigerant and compare the weight to that specified but in a DIY (and aircon is no longer a DIY task given the legal requirement for F-Gas certification) situation, a pressure measurement (for which you really should have F-Gas certification as you're opening the refrigerant circuit) is a very rough indicator, nothing more.
And yes, I know fleabay is awash with 'top-up cans', it's only a matter of time before someone cottons on and they're prohibited from sale.
A 2015 Mazda may well use R1234-YF, in which case, the pressure values will be slightly lower, but the 3Bar minimum will be the same.
If you have access to gauges, this may be of use.
www.vehicleairconservices.com
And yes, I know fleabay is awash with 'top-up cans', it's only a matter of time before someone cottons on and they're prohibited from sale.
A 2015 Mazda may well use R1234-YF, in which case, the pressure values will be slightly lower, but the 3Bar minimum will be the same.
If you have access to gauges, this may be of use.
R134a Pressure Gauge Readings
How to interpret R134a pressure gauges. Understanding air conditioning gauges.
www.vehicleairconservices.com
The AC compressor will typically be controlled by the engine ECU, so you'll usually find AC pressure readings there.
Other modules do get used in some vehicles, but I've got no idea about Mazda specifics, although the few times I've had to deal with them, diagnostic coverage hasn't been the best.
Jack_K
Member
- Messages
- 617
- Location
- Australia
Does it have a simple type pressure switch or is it too new for that?
There are legal ways to purchase R134a and there are some other options which are even easier. I don't recommend getting into DIY AC though as the tools add up very quickly if you want anything half reasonable. I did it since I experienced too many "professionals"
There are legal ways to purchase R134a and there are some other options which are even easier. I don't recommend getting into DIY AC though as the tools add up very quickly if you want anything half reasonable. I did it since I experienced too many "professionals"
premmington
Member
- Messages
- 7,100
- Location
- Norfolk
In a workshop environment, a pure pressure check isn't reliable as it doesn't really indicate how much refrigerant is in the system. Ideally you'd recover the refrigerant and compare the weight to that specified but in a DIY (and aircon is no longer a DIY task given the legal requirement for F-Gas certification) situation, a pressure measurement (for which you really should have F-Gas certification as you're opening the refrigerant circuit) is a very rough indicator, nothing more.
And yes, I know fleabay is awash with 'top-up cans', it's only a matter of time before someone cottons on and they're prohibited from sale.
A 2015 Mazda may well use R1234-YF, in which case, the pressure values will be slightly lower, but the 3Bar minimum will be the same.
If you have access to gauges, this may be of use.
R134a Pressure Gauge Readings
How to interpret R134a pressure gauges. Understanding air conditioning gauges.
+1
(even I have a F gas ticket now!)
Is that from eating sprouts or beans,?
ms08
Member
- Messages
- 639
- Location
- Kent
Run a jumper wire from the battery directly to the clutch to see if engages then bypassing the system.
I did this on my Saab 9000 to check if enough gas in the system to run the a/c.
If it does then an electrical problem.
I have set of gauges now to check if i need to. From ebay for about £30 but if you can borrow a set.
I did this on my Saab 9000 to check if enough gas in the system to run the a/c.
If it does then an electrical problem.
I have set of gauges now to check if i need to. From ebay for about £30 but if you can borrow a set.
Honestly, just take it to an AC specialist. I know a bit about how these things work but after months of chasing an intermittent fault on my Audi it turned out it needed a new dryer and a good chunk of gas. The dryer was full, and despite having sensible pressure, there was only 120 grammes of gas against the quoted half a kilo.
I just got a specialist to replace the dryer, leak test it all (was fine) add the correct amount of gas and some lubricant. It's now back to factory fresh and only cost me €100. That's cheap, but bear in mind AC is not a luxury in Spain so there are a lot of places who fix it, but even at a higher price it is well worth having the full service. One of those sets of gauges off the bay only show you pressure, not weights and the cheap sets can't pull a vacuum for leak testing or refilling.
I just got a specialist to replace the dryer, leak test it all (was fine) add the correct amount of gas and some lubricant. It's now back to factory fresh and only cost me €100. That's cheap, but bear in mind AC is not a luxury in Spain so there are a lot of places who fix it, but even at a higher price it is well worth having the full service. One of those sets of gauges off the bay only show you pressure, not weights and the cheap sets can't pull a vacuum for leak testing or refilling.
dobbslc
Member
- Messages
- 14,168
- Location
- Hertfordshire UK
It's cabbage up his way isn't it?
premmington
Member
- Messages
- 7,100
- Location
- Norfolk
Sprouts or beans do not have this effect on me...
Raw grated beetroot on a salad - even the dogs have to leave the room
Exactly this, you will usually see low pressure on air conditioning circuit in the fault list and also how many bar/mbar is in the system on the live data output. It doesnt have to have some, it has to have over a set amount the ecu checks for before turning the clutch on with a modern setup. If you have a system that sometimes works and sometimes doesnt, it can be the gas pressure right near this trigger value and flip flopping with conditions on the day...
After owning a Ford Galaxy people carrier with dual outlet aircon that was constantly messed up by the aircon people because it wasnt in their lists and they kept putting the wrong gas quantity in I have the stuff to diy now and life is much nicer.
JOEPRO
Member
- Messages
- 5,535
- Location
- UK
If it's just low on gas then where did the gas go(?)
Have the garage add UV Dye to the system when refilling as this will at least leave a mark where it is leaking from.
