Evaporator Temperature Sensor

[PoloGaz]

Changed the evap sensor on mine today and not resetting the fault codes has resulted in it making no difference to how good the air con is. Has anyone else had the opposite experience from changing it? Also it looks like it has been changed before, the ECU bracket thing was already broken.

I guess it could be that it has no gas. :confused: The recirc button doesn't turn off so I'm guessing the flap motors are ok. The two fans in the engine bay on the rad dont spin with the aircon on. From what I've been reading on here they should be, and thus points to a problem :confused:

A Vag-Com cable is on order.

[Tech1e]

Indeed you need a fault code check to know where to start.

[echase]

To pologaz

If you pull out the plug and wire 5 volts (not 12V, although I did try it briefly, but was advised it may blow it up) e.g. from a mobile phone charger, across the 2 connector pins on the pump (either way round) it should override all the electronics and get the cool air flowing. That is unless you have no gas or a dead pump.

If the fans then kick in chances are your fault is a small one, like the temperature sensor.

Don’t run it for long though as you have overridden all the sensors this way and it could overheat or overpressure the gas if they is a more complex fault like a blocked pipe.

This is just to help with diagnostics.

[PoloGaz]

Thanks mate, I'm gonna leave it till my VAG com cable arrives. See if there's owt logged and start a fresh. Lets hope it works!

[PoloGaz]

Cable arrived this morning. Had to hook it up to a normal PC as I don't have a laptop. Got this fault code on the aircon:

1 Fault Found:

00819 - High Pressure Sensor (G65)

07-00 - Signal too Low

So it sounds like I have no Gas? I got the fault to clear temporarily but within a few seconds it came back.

[ap0gee1978]

Looks like the Evap Temp Sensor's gone on SWMBO's car now! The air con blows cold when the car first starts up, but then stops after a few minutes and doesn't work again until the engine's completely cold. :thumbdwn: I've got the sensor on order, and will take some piccies as I do the job...

(Might even use the proper camera this time! )

Any advances on whether you definitely have to clear the fault codes to get the air con working again? Seeing how it works at first (presumably while the evaporator's still at ambient temperature) it would appear that the fault code doesn't bar the air con from working altogether. I don't want to have to bother anyone with VAG-COM if it'll work happily with the fault codes present until next time it goes to the garage... :confused:

[devonutopia]

Is the Evap Temp Sensor the same as "High Pressure Sensor" ??? Mine's throwing up a "signal too low - 00819" for this sensor, but I've never heard of it. Am I going to be performing an unsighted examination of my dashboard internals too?

[ap0gee1978]

There's what appears to be a pressure sensor on the high pressure (i.e. hot) refrigerant line roughly between the nearside headlamp and the wheel arch. It's dead easy to get to on SWMBO's 1.4 MPi, but I can't see the equivalent part on my vRS (in fact the two systems look completely different!) There's probably a pressure sensor on the low pressure side too, but I don't know where that might be. Don't know how you'd remove the sensor without all your gas escaping, either.

Judging by Pologaz's earlier posts, it might just be a lack of refrigerant in yours. The wife's car's already been to an air con place, and although they couldn't fix it, I presume the first thing they'd have done would have been top up the gas!

[ap0gee1978]

Illustrated how-to now posted here, if anyone's interested...