Can I damage the ECU or MAF with these circuits?
No. The ECU will not be damaged by MAF voltages between 0 and 5 volts. These circuits only lower the MAF voltage a little, so no problem. The MAF will not be damaged either: the resistance is very high and the MAF will be fine.
Page Last updated: Sept 1, 2003
Mass Air Flow converters
On a rainy Monday, when you're late for work, suddenly your TDI looses power. I turns out that your MAF has gone bad. You can get another MAF for a small amount of money, but the MAF you need is a Pierburg and the MAF you can get is a Bosch. And when you needed a Bosch, you could only get a Pierburg for a fair price. But you remembered a post on the TDICLUB web page or your search engine found the web pages of TECH4TDI. So here you are.
Below you'll find the schematics of two converters, together with data from the MAF manufacturer and measurement data of the converter. But first some global information:
No IC's, large temperature range
The first thing you may notice looking at the circuits is that it seems quite simple. Just a few resistors, transistors and one or two capacitors. No IC's. You could make the same circuit with IC's, but it would be more expensive, less robust and no better performance. But most of all: the temperature range of normal IC's is too small. The circuits below are fully temperature compensated and can handle a temperature range of -50deg.C. to +125deg.C. without any problem. IC's for this range would be expensive as they have to have military specifications.