P3 IAT reading incorrect

[Traptalk]

Hey everyone got a p3 vidi for my b8 and everything seems to be working except the air intake temperature readings.

Initially the intake temps were reading the same as ambient temperature or outside temperature your dash would display.

I called p3 and they walked me thru the config settings. Apparently when you buy from p3 they configure for either a4 or s4 but ecs Tuning does not. Mine came defaulted for 3.0T.

However even after changing the config settings to the one p3 said was correct my IAT are reading about 40F below what my cheap actron scan tool reads thru obd2.

Anyone else have this issue?

[old guy]

I would tend to also question your Actron Scan Tool. What is the average delta between your ambient, Actron and P3 readings? Typically when my car is in motion my IAT is around 8°→12° above the ambient temperature. The only time I ever see a 40° delta would be when I get stuck in Baltimore gridlock traffic on a really hot day. Engine is basically stock 2.0T with a 3.0 TDI FMIC.

Another quick check. When your engine is completely cold (overnight) check your IAT, CTS and ambient temperatures. Compare the P3 to the Actron. They should all be within a degree or two of each other.

[Traptalk]

I would tend to also question your Actron Scan Tool. What is the average delta between your ambient, Actron and P3 readings? Typically when my car is in motion my IAT is around 8°→12° above the ambient temperature. The only time I ever see a 40° delta would be when I get stuck in Baltimore gridlock traffic on a really hot day. Engine is basically stock 2.0T with a 3.0 TDI FMIC.

Another quick check. When your engine is completely cold (overnight) check your IAT, CTS and ambient temperatures. Compare the P3 to the Actron. They should all be within a degree or two of each other.

Yeah that sounds about consistent with my p3. Today is significantly higher in temperature here and I’m seeing the actron still reading about 140F which it did the other day while it was 20 degrees cooler outside. Also p3 shows a difference from sitting still to moving and the actron has too many PIDs to update as fast as the p3 but barely any fluctuations while moving vs stopped