Water down the car, scrub it down with a washing brush and some soapy water, rinse it off, then dry it off.
Theres four o2 sensors in this particular bmw. Two before and two after the cat converters.
4
Some 323 bmw's in the E36 platform only have 2 O2 Sensors, 1 pre cat and 1 post cat, unlike other BMW's that actually have 2 on the exhaust manifolds (1 per manifold) and two sensors at the cat for a total of 4 sensors. This might be a bit confusing but BMW went with a simpler design on the 323 E36 I don't know why.
You must replace the brake pad sensors inside or on the rear calipers... usually that is the reason why a brake service is more expensive on a bmw. all due to sensors and the availability of those sensors
On the exhaust pipe 1 before the cat and 1 after
4, one per wheel
There are four speed sensors on a 99 BMW 328i. One sensor is located on each of the four wheels.
The O2 sensor is in the exhaust pipe before the catalytic converter.
there are 2 pre and two after
you cant need to do sencors to sorry
4. 2 pre cat, 2 post.
also, are any special tools required?