Newbie here with a small issue with S4 .

My S4 wont start and comes with a speed signal G28 fault .
I dont have the correct wiring diagram for the car and need to know a few basic things :

What three colour wires are there on the plug to Speed sensor and what pin numbers do they
go to the ECU ?

Should the Engine speed sensor have a constant 5v power supply and the crank trigger alter this ? What the best test for this ?

I hope someone can help me out , Im kinda thinking my ECU is cactus

 

first... get eBahn, that'll be the best 80-90 bucks you have invested in your car.

The below information is based off my interpetation of what I am reading.

It looks like the information your looking for is like... I BELIEVE because I don't read wiring diagrams for a living...

Black wire to the switch
Blue wire to the ECU (Grey plug in engine compartment) at number 90
Green wire to the ECU (Grey Plug in engine compartment) at number 82

It also says that... but I have no idea what the means.

Black - T3m/1
Blue - T3m/2
Green - T3m/3

and T3m is the 3 point grey wire connector in the engine compartment.

I hope I am reading it right, but again, I'm not sure.

Shawn