I posted this in a reply to a similar problem elsewhere on the forum but I suspect I posted in the wrong place as I didn't receive any response. My apologies if I am duplicating the post.
Anyway I have a problem with a 2015 Mk8 Euro 5 engine with 38K km on the clock. The ACT ( Air Charge Temp ) is reading 45C at startup, despite the ambient temp reading 10C. Once it reaches circa 70C, which happens very quickly, the engine service light comes on and it goes into limp mode. I know that the intercooler is not helping to lower the temperature as the vehicle is stationary, so not sure if this rapid rise in temp is as such normal. Does anyone have any idea of what a normal ACT would be for this engine when the vehicle is idle ?
Additionally I have removed the intercooler ( ACT ) sensor and tested same with an ohm meter. It appears that the sensor is working, as the ohm reading drops when hot air is applied. However without having the factory spec for the sensor, I can't tell whether it's working as designed. I suspect not and propose to purchase a sensor to eliminate this sensor from the equation. In the interim, would anyone know what a normal Ohm reading should be for this sensor ?
I have also checked the pipe work on both sides of the intercooler and all seem to be in good condition i.e. no holes or leaks as far as I can see, so I am pretty sure it's a sensor issue.
Finally could somebody just confirm that there are only two air temp sensors. A sensor just in front of the Air box which I believe is a combination MAF and Intake Air Temp. If I remove the wiring connector I loose the MAF and Intake Air Temp on the live readout so suspect the IAT is part of the MAF. The second sensor appears to be the Air Charge Temp sensor on the outlet side of the intercooler. Is that it or have I missed a sensor somewhere ?
Finally it looks to me that the MAP sensor is on the plastic air intake just below the throttle box housing. Is that correct ?
Any suggestions, photos or info. would be much appreciated. All very difficult without a manual. Seems Haynes have as yet not produced a manual for
the Mk 8.