LMM at 2.5 AKE: A Comprehensive Guide

Hi,

I've read so much about contaminated Mass Air Flow (MAF) sensors that I decided to check mine. I expected to find a Bosch MAF sensor that was heavily soiled and black.

I found a pure white (ceramic heating element?) from HITACHI.

???

Why was the Bosch replaced with a Hitachi? And why doesn't it get dirty?

Do you have any experience with that?

Okay, the car is an Audi A6 2.5 TDI AKE, first registered in May 2001, and currently has 147,000 kilometers (approximately 91,000 miles) on the odometer.