I recently replaced the O2 sensors on the S54 engine. Just want to let you guys know that the e46 m3 will have different locations for the O2 sensor and possibly different locations for the other sensors. Another thing to note is that the location for anything exhaust related, such as O2 sensor, will be different depending on if your car is from North America or Europe. Hope this helps and thank you for the video as well!
I believe the vehicle speed comes from the ABS wheel speed sensor on the rear-right wheel. If you take off that wheel and look behind the rotor you should see two cables. One set is for the brake pad wear sensor and the other goes to the one you need. But before you just jump straight to the sensor, you should get a scan tool and double check if the DME is getting vehicle signal as you're driving. Damaged wiring or a busted instrument cluster/dash can also be the culprit. This sensor connects directly to the ABS, ASC or DSC unit, whichever one you have, before it gets passed off to the DME.
No MAP sensor. I believe it only uses MAF and IAT sensors to measure amount of air for the air/fuel ratios. On other cars that do use MAP sensors, you usually find it either on or around the intake manifold.
