
Originally Posted by
sal71
At smac so what does that mean in terms of wiring. I realize one wire has to be positive and the other negative so what would be the other 2. The colors of the wiring diagram do not match the pump
You need to read up on what single phase pump vs three phase pump means.
https://youtu.be/LqgxAG-KUe0?t=1110
You have a 2013 A4 allroad according to the profile. So that's B8.5, which means it uses the three phase VDO pump. So the B8.0 pump controller takes the 12v power and the PWM command from the ECM and turns that into a single phase powering of the Bosch single phase pump. The B8.5 pump controller takes the same but turns it into a three phase powering of the VDO three phase pump. Thus three wires and ground. If your aftermarket pump is a single phase, you're not going to be able to drive it using the B8.5 pump controller.
As for the wiring colors, the wiring diagram documents the wiring harness. To the plug that connects to the pump. Your pics are of the wiring "inside" the pump; the wiring diagram does not document "into" components. You'd have to backtrack the four wires to the connector on the top to see which is on which pin. The wiring diagram says pin 4 is ground, but it doesn't explain which of the three other pins are phase V, phase U, and phase W.
Can you replace the B8.5 pump controller with a B8.0 pump controller to get a single-phase pump output? I don't know. It's not a complicated system, but I don't remember if the PWM switching frequency changed with the B8.0 to B8.5 transition.
B8.0
1 - + to pump
2 - ground to pump
3 - 12v from fuse
4 - ground to chassis
5 - PWM from ECM
B8.5
1, 2 ,3 - + to pump
4 - ground to pump and to chassis
5 - 12v from fuse
6 - PWM from ECM
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