Audi CQ20V ABS problem

[M2ki]

Big pins on big black relay. 30 & 87

[Tom_]

Thanks a lot ...what about that second relay?

[Tom_]

And second thought, what about bleeding ABS? Any "how to" do that with no diagnostic? Maybe this can make that ABS LIGHT ON...what u think?

[M2ki]

Dont think that, it is a very basic system, from the early 80s.
Did you short the pins and did the motor started working?

[Tom_]

Not yet, tomorrow i will do that, because yesterday/today i am whole day at work. When i do this, what i gonna expect? Some sounds from pump ?

[Tom_]

M2ki So i try to bridge that black abs pump relay and still after start ABS ON...

[M2ki]

Dont leave it bridged. Just bridge it for a second or two.
You should hear a sound of electric motor.
If you dont. Then the pump is broken.

[Tom_]

M2ki I removed that black relay, start engine and then bridged that two pins, but i cant hear anything due to my exhaust Any different option how measure ABS pump ? OR how noisy should electric motor be?

[M2ki]

Don't start the engine then
Pin 87 is alwyas hot in this pump. It means its straight from the battery.

J105 in the schematic
http://www.s2central.com/S2_Schematics/D/D26.pdf

[Tom_]

I try it with engine off to bridge those 30 and 87 pins, but nothing...

[M2ki]

Then there is probably your ABS problem. Dead return pump motor.

Working older ABS systems will do prrrrt sound and you can feel it through the brake pedal.
I'm not 100% but I think the abs ecu turns on the pump relay for a second to verify if the abs return pump works. If it does not in your case, then it will display abs light on dash.

[Tom_]

M2ki Is there any option how to be 100% sure? I buy some other used pump, but i want to be sure...I only hear ticking from the relais i think...No prrrrt at all can u record that sound?

[M2ki]

If your motor is dead, then there can't be any prrrt sound after the ignition

You can measure voltage between pin 87 and pump chassis, should be same as battery voltage.

[Tom_]

****, its noisy No this noise is not coming from ABS pump at all Ok i check voltage

[M2ki]

That other prrrt sound after ignition, i'm not able to record that, its windy outside and its pretty quiet in the cabin. Only lasts lass than half a second.