I came across a 2012 1.6tdci mk3 today that had an issue where we had ignition lights but no crank. After the key was release from the crank position an error message would appear on the display saying “Steering Malfunction”.
After investigation we found that although there was power to the grey relays in the engine bay, there was no switched earth. Now the earth has to be be present only when the ignition is on/engine running but this wasn’t the case. I’d imagine this earth is fed out from the immobiliser.
After splitting the fuse box and tracing a green/purple trace thin wire back down the loom towards the direction of the abs pump, beneath the battery tray, we found it had snapped at the 90° angle as the loom turns to the left.
Simply opening the loom up and replacing a section of this wire has cured the issue!
It maybe worth checking this section of loom should any other electrical circuits stop working due to the tight turn in the loom / faulty manufacturing.
its worth noting that a temporary earth taken to these relays will get you off the road to a garage but running an earth full time will leave the relays energised and flatten the battery hense it’s better to find the broken wire.