[Dylan86]

Having an intermittent fault code upon cold starts and the first five minutes of driving. It’s “10C004 - charge air temperature sensor, plausibility, cold start: temperature too high” and then Reduces power mode. Once the engine comes up to temperature, I restart the car and it has no faults, or power limitations.

I had this code once last year, and didn’t think much of it, as my readings from the IAT gauge were still looking good, and fluctuating as they should, on WOT pulls, etc. Now, more recently, I’m getting this code on every cold start, and the readings on my JB4 are stuck permanently at 77*C, which is really off, way too high.

So it’s pretty obvious I have an IAT sensor issue, my question is, which sensor is it? There are two, one on the charge pipe below the TB, and one on the intake manifold toward cyl 6. The JB4 is plugged into both IIRC, how do I diagnose the faulty sensor ? I did pull the one on the charge pipe to inspect, and it was crystal clean. I have a feeling since I started using meth, that the one in the plenum could be the culprit, and I’ve heard of meth eating sensors over the long run, but this was only 6-7 months of meth usage, anyway..

Hoping someone can shed light on this, from a diagnostic standpoint. I will most likely swap the two sensors around, or at the very least, inspect the other sensor for any dirt/grime/damage before going ahead and buying an IAT sensor to try.

What I’ve seen through researching the N55, is that the IAT and MAP sensor is a shared piece. What’s odd is that there’s two of them, lol. One must be the dominant IAT and MAP sensor, but which one?? That’s where I can’t seem to wrap my head, around things.

Appreciate the help, we’ll check back in a bit after I pull the other sensor, and hook up some live data analysis on the SnapOn Modis

[bryan_G01]

email Terry at bms and ask what sensor jb4 is reading off of. Thats the quickest way i can think of.

[Dylan86]

Originally Posted by bryan_f22

email Terry at bms and ask what sensor jb4 is reading off of. Thats the quickest way i can think of.

Done, thanks Bryan.

Q: Does methanol have ill effects to IAT/MAP sensors, typically?Just want to know if I should expect this again, in the future... I never had issues regarding the IAT faults until shortly after starting the meth journey, last summer.

D

[Dylan86]

In the meantime, I've logged the live data for Air Intake Monitor and came up with this:



While hooked up, and engine running I first unplugged the sensor mounted to the manifold, and nothing changed, no fault codes or short-to-ground errors from it being un-plugged, either (strange), and still "frozen" at 172.4*F (77*C). Plugged it back in and then unplugged the sensor on the charge-pipe and wha-laa, the data dropped off immediately, codes all came on with this one as well.

That said, the sensors are 100% the same, part# and all. I'm going to swap them this afternoon after things cool off, and see how it goes. Also awaiting BMS's response, as well, but it seems I've answered my own question, already. I did ask for an explanation of the two sensors, and how they differ/function with regard to data monitoring and DME control. One has to do one, or the other, can't imagine both working in a "synchronized" fashion. Correct me if I'm wrong, I know very little about BMW's DME control, etc, this is a big learning curve for me.

D

[Dylan86]

Terry responded, quickly! and verified that the primary IAT/MAP sensor on the chargepipe is what the DME/JB4 are using to collect the primary data. The sensor on the manifold, although an identical part# is only used for secondary MAP reading, no IAT reading or data collection. So I could, in theory, just swap the two sensors around. I might do this and see if it'll hold me off until I can order in a 3.5bar N20 replacement sensor. Might as well if I'm going to be buying a sensor anyhow...

Hopefully this experience will help someone else in the future. I'm sure this will become more "common" among this platform as end users modify their cars, and as the lifespan ages. Thanks,

D

[amw896]

why the n20 sensor?

[bryan_G01]

Originally Posted by amw896

why the n20 sensor?

allows over 21 psi...

[amw896]

Nice, thanks!

Originally Posted by bryan_f22

allows over 21 psi...