I got a fault code P2015 for the intake manifold runner flap at the same time as this P1927 code for the auxiliary coolant pump. Currently I'm replacing the old tensioner in it as well as carbon cleaning since I had to replace the intake manifold, so I can't start it up, do you have any information on which relay controls the auxiliary pump ? I've done some work on my car before but never anything electrical so I'm a bit lost on how to troubleshoot these things, thanks!
Maybe this will help. Do you have a multimeter to test circuits? I would start by checking the fuses that say aux pump fuse. This system is a bit strange and complex. I think fans have to come on first for the aux pump to come on.
Nevermind all that, just set your meter on continuity and check the fuses. When you touch the leads together it should beep? Yes? Ok now on top of each fuse there are 2 little spots. Stick each lead to the spots see if it beeps. Yes? The fuse is good.
A relay is a bit more complicated. You would need to put 12v power to it to test it. If fuses are good I would just get a new relay.
You can take the aux pump off and put 12v power to it and see if it comes on, that would eliminate the pump being bad