The latest fault on my Octy II 2.0 TDI elegance is that the climatronic has screwed up. What is happening is that owing (perhaps) to a sensor somewhere, the radio display and LCD panel between the dials reads anything from -25C to 2C of late, all of which are massively wrong. This results in no compressor (no air conditioning). The fault started off as intermittent and left no fault codes, so that on the last service the dealer couldn't do anything (actually couldn't be r-sed to look more like). Now it seems permanently faulty.

Before taking the car to a dealer for a warranty repair, does anyone have experience of this? Anyone know where the sensor can be found that provides the data ? (just in case it's a bad connection).

Thanks

Forgive me for sounding stupid but the sensor for the climate control is on the inside so it regulates that temperature. The sensor on the outside does not make a difference, the compressor is switched using the econ or auto switch.

Forgive me for sounding stupid but the sensor for the climate control is on the inside so it regulates that temperature. The sensor on the outside does not make a difference, the compressor is switched using the econ or auto switch.

Yes, the internal sensors are used to control internal temperature as you say, but I meant the sensor that gives you the -external- temperture reading that can be seen on the radio's LCD panel (and the LCD readout between speedo and rev counter).

If this external temperture is measured at less than 4C (IIRC from the manual) the air conditioning system's compressor is specifically blocked from coming on, in order to aviod damage from icing up. This is correct behaviour.

My problem is that when the external temprature is genuinely at 20C+, I do want the air con to come on (I know what econ button does!), BUT if the system is incorrectly reading the external temp as say, -2C, the air-con never actually starts. The system is fooled into protecting itself from frost even at this time of year!

I figure therefore that given there may well be problem with the external temp sensor, knowing where to locate it would be a good start in fixing it. It should only be a thermocouple that is wired into the ECU or air-con electronics somewhere....

Also, I am concerned that this same external temp sensor may be used to determine fueling parameters - maybe I'm wasting fuel because the car will certainly take into account ext. air temp when calculating correct fuel/air mixture.

Any help appreciated.

Also, I am concerned that this same external temp sensor may be used to determine fueling parameters - maybe I'm wasting fuel because the car will certainly take into account ext. air temp when calculating correct fuel/air mixture.

Not on a diesel you won't. This could be the case on a petrol engined car, but even then there would be a seperate sensor on the inlet manifold and engine coolant system.

On the Octy 1 the sensor is clipped behind the bumper somewhere, I had similar problems & as it was under warranty I let the dealer look at it, aparently the wire had come loose on the sensor, not off but enough to **** the readings. On the Octy 1 you had no air con when the external temp was below something like 4 degrees. After a few miles mine would slowly come up to give a normal reading before it was fixed.

Hope this helps a bit

On the Octy 1 the sensor is clipped behind the bumper somewhere, I had similar problems & as it was under warranty I let the dealer look at it, aparently the wire had come loose on the sensor, not off but enough to **** the readings. On the Octy 1 you had no air con when the external temp was below something like 4 degrees. After a few miles mine would slowly come up to give a normal reading before it was fixed.

Hope this helps a bit

Yes it does help - it's a start at least, because I doubt that there would be compelling reason to to move the temp sensor from behind the bumper when designing the Mk2 (compared with MK1), so I'll take a look there.

I hope the front bumper removal is simple!!

Yes it does help - it's a start at least, because I doubt that there would be compelling reason to to move the temp sensor from behind the bumper when designing the Mk2 (compared with MK1), so I'll take a look there.

I hope the front bumper removal is simple!!

Havent got a car near me at the moment & cant remember where it is but its not a bumper off job on the Octy 1, stick a question up, anyone know where etc etc & some of the techies should be able to guide you, It might be just popping out a front grille

Stuart

Havent got a car near me at the moment & cant remember where it is but its not a bumper off job on the Octy 1, stick a question up, anyone know where etc etc & some of the techies should be able to guide you, It might be just popping out a front grille

Stuart

OK - thanks for that, I'll take a look this w/e.

I already asked where to find the temp sensor, but got no replies other than those above.

Not on a diesel you won't. This could be the case on a petrol engined car, but even then there would be a seperate sensor on the inlet manifold and engine coolant system.

I know diesels are fueled differently, but I assumed that since the mass flow sensor is not strictly a mass flow sensor, but in fact a volume flow sensor, accurate temp readings would be necessary as part of look-up operation in ECU to derive the actual air mass in order to then calculate the correct fuel delivery for the burn. Also, you need a control to drop pressure on the turbo or back off fuelling if for some reason the charge temp was getting to hot.

The right place for this sensor would probably be as close as poss. to the MAF. And, thinking about it, you'd still need a separate sensor for true outside temp readings because the air entering the MAF is compressed by the turbo and so is hotter, irrespective of any intercooling.

As it happens, I have been pointed in the direction of the front bumper/grille area to find the sensor that is giving me problems...