The Mégane II Owners' Club

HI,

I have bought a Sport Tourer couple of months ago. The aircon was not working. Now I took it for a regas, the garage filled it up but said it is still not working. I have booked it in for an inspection and they said it is probably the pressure sensor. I have bought a sensor which I have changed myself but no joy. What I have noticed is, when changing a sensor no gas escaped, so I have tried to push the little pin in the middle of the valve to find out whether it is working. When I pressed it there was no sshshhhshh or similar noise indicating escaping gas - could someone please help with this e.g. is this little valve which is built in the air con pipe not working properly? Have someone tried to change the sensor themself, if so, what was their experience? Was the gas escaping from the system while screwing in the sensor?

Many Thanks for your help in advance

If your air-con was out of gas when it was first looked at, it is likely it stored a 'cold loop' code in the engine ECU. This prevents the A/C from running when the system is empty to stop pump siezures. When the system is refilled, the code must be cleared for the A/C to work again. The pressure switch shouldn't vent gas when removed, even if you press the centre pin in the union which I wouldn't recommend. ECU codes might be worth looking into.

Thanks Skid,

What sort of equipment would I need to check the codes - I dont really want to take the car to a garage or Renault themselves as i dont trust them.
Thanks,

Renaults CLIP diagnostic tool will show it for sure if it's logged but there's plenty of generic EOBD code readers about that might show the code if it's logged. Might be worth scanning this forum as they get mentioned quite often.

A/C problems can be a nightmare. If it was empty this could be caused by a leak. If there is a leak, moisture might have entered the system and this can cause significant damage.

What your garage should do is empty the system completely. Then vacuum pump it to dry it; pressure test it using nitrogen, fill it with the correct amount of R134a and oil; test it again for leaks using either dye or a 'sniffer'.

Assuming that has been done correctly and you have no problem codes, I'm not sure what the next step is. What I wouldn't do is replace any more parts until you have more information.

I have bought a diagnostic tool, which arrived today. I have connected it to the car and it showed an error code P0381 - Glow Plug/Heater Indicator Circuit Malfunction.

Could this error code prevent the air con from working e. g. the compressor kicking in? I am thinking about erasing the code to see whether it helps.

Skidms9 wrote:Renaults CLIP diagnostic tool will show it for sure if it's logged but there's plenty of generic EOBD code readers about that might show the code if it's logged. Might be worth scanning this forum as they get mentioned quite often.

I doubt this is related. Investigate whether the glow plugs are working. It is a simple test.

Hi Dave,

I am not sure how to test the glow plugs. Could you describe in more detail, please.

As above, a glow plug fault will not effect A/C operation/function and if there's no physical pressure in the system theres the root cause. Next you will need to find out why as also directed above and I've not seen a single ELM based product that will show you the cold loop info other than CLIP.

Find a decent A/C specialist in your area and let them loose. I've just re-gassed my setup on the wife's dCi 80 and thankfully it's just because she never used it and the seals had dried out. New seals and all chilled again and she got a smacked arse (but that's another story for another day).

Mick

Hi Mick,

At first there was no pressure in the air con, so I took it for regas. In the garage they filled it up but said the compressor is not kicking in, so I left the car with them to diagnose the problem. They called me saying they think it is the pressure sensor, but they quoted a horrendous amount for the sensor+labor. At the end I bought a sensor online and changed it myself, but air con still not blowing. If I take it to a specialist, it will cost me a lot, which I cannot afford at the moment. I will try to find a cause myself or with your help guys.....hopefully

Are they/you sure it's the physical pressure sensor at fault? I've had a CC in my workshop today for a major service which was showing a sensor open circuit fault on CLIP. Unplugged it, cleaned the connector and tightened up the three pins in the loom side multi plug and guess what... A/C function restored!

You really should take it somewhere that has access to CLIP. It's easy enough to rule out certain issues of which the switch and compressor maglock function are just two.

Mick

Update:

I have ordered a pressure sensor online and changed it myself. Nothing changed.

I have measured the voltage between the 3 pins which are plugged into the sensor, but showed the same voltage when the fan was on or both the fan and air con was on.
There is another 2 pin plug which goes to compressor, but again, the same voltage occurred when the air con was turned on or off.

I am not sure, what to do next.I might check the wiring...does anybody by any chance have a wiring diagram for the aircon please

Has this issue been solved?

Same issue here, Kwik fit (I know!!) said regas didn't get it going, no leaks etc

Have heard of broken wire from the fuse to compressor, anyone know of this, which wires go to the fuse?