Does anyone know how to activate auxiliary water pump with VCDS?

[allroadadi]

Long story short, the electric water pump died under the intake manifold. Not only that but the electrical connector at the water pump has disintegrated. It literally crumbled into little pieces (heat, I’m assuming).
Got a new pump, new connector. I did check the wiring diagram: brown is negative, red/blue is positive. I do want to test it out before I put the manifold back. For those who did it in the past, they know how much of a pain is to remove the manifold. It’s my 3rd time, and I’m still not happy doing it. Not to mention each time I removed the entire front end. Each time though it was for other work as well (timing belt, once, alternator and power steering the 2nd time, etc.)
There’s gotta be a way to test it by using the car electronics and not run power to it (already did that and it’s running). But also want to see if the other parts of this system work so activating it with VCDS would be ideal…

[Shoppinit]

If you can do it, then it will be with the output tests on the ECU module with VCDS. I can't remember off-hand whether it's one of the outputs that's activated. I can check later, possibly.

[allroadadi]

Tried it. It does not have the option under the output test. It activates only the SAI pump (secondary air injection).
Looking at the service manual all the tests prerequisites start with engine warm to at least 90C (can’t remember specifically the temperature) if temperature not achieved drive car until temperature is obtained. Then proceed with all tests (electrical, voltage at the connector, etc, or mechanical which is listening).

[HPsauce]

Is this a different/additional unit to the Auxiliary Water Pump in a D2 A8/S8? Because that just runs all the time AFAIK, don't even think you can see it in VCDS.
The only separate way of controlling it is when using the residual heat system when parked as that turns it on so there must be a relay somewhere.
Again, might not be relevant, but the D2 version (which I'd expect to be very similar if not identical) has a habit of getting a very noisy motor and people then usually disconnect the power supply, the water pump suffices for the engine and the cabin heater just takes a little longer in winter.

[TOPMAN]

Tried it. It does not have the option under the output test. It activates only the SAI pump (secondary air injection).
Looking at the service manual all the tests prerequisites start with engine warm to at least 90C (can’t remember specifically the temperature) if temperature not achieved drive car until temperature is obtained. Then proceed with all tests (electrical, voltage at the connector, etc, or mechanical which is listening).

You should be able to hear it even from cold. Just tried it on mine, turn the ignition on (no need to start engine) and turn off, put ear to air filter. If you can't hear a slight whirring noise from the pump it's probably not working. It's a hostile environment under that intake manifold and these plastic pumps take a beating. If it hasn't been replaced in its life, I'm quite sure it will need doing. I did mine last year, the same time I replaced the SJP and a bunch of other stuff.
If you remove the airbox, it's the green plug closest to the bulkhead, check it for 12v after a quick ignition flick as mentioned earlier in this post. If you find the 12v supply then you can try supplying directly and see if you hear anything...

Good luck - happy to help if you need

Regards
Craig Barlow

[TOPMAN]

Is this a different/additional unit to the Auxiliary Water Pump in a D2 A8/S8? Because that just runs all the time AFAIK, don't even think you can see it in VCDS.
The only separate way of controlling it is when using the residual heat system when parked as that turns it on so there must be a relay somewhere.
Again, might not be relevant, but the D2 version (which I'd expect to be very similar if not identical) has a habit of getting a very noisy motor and people then usually disconnect the power supply, the water pump suffices for the engine and the cabin heater just takes a little longer in winter.

Hello HPsauce

It's a physically a similar pump to the additional coolant pump found on the D2's but the use is different. On the C5 RS6 it is used as an after-run coolant pump, acting in a similar way to an old school turbo-timer, in that it's designed to flow water through the turbos after a drive. It's all controlled by the coolant circulation pump relay which is control by the ECU. This pump actually flows the water in the reverse direction and the idea is to prevent vapour bubbles building up around the area of the turbos. The ECU takes into account variables from ambient temp, oil temp, coolant temp etc etc.

Regards
Craig Barlow

[Shoppinit]

Ill have a look on mine later to see if I can find an output test.