The power steering on my Fabia 1.4 failed with dash warning light on after being intermittent for a while. When I tried to check for a fault code I got a "link error" when scanning for A/T codes (Engine and SRS scans still work).

I checked the wiring to the pump and it had good feeds from the battery and ignition and I measured 2.6V with a DVM on the CAN wires, which seems reasonable.

I've now fitted a second-hand pump from an Ebay seller but I've got exactly the same conditions so I'm wondering if I've got another duff pump or some other fault.

Any advice on where to go next?

Probably your battery.

DB.

What are you scanning with?

It's the same with a fully charged battery.

I'm scanning with an Autel vagscanner VAG305. It used to work on A/T before the power steering failure.

You say you have checked the feeds from terminal 30 and 15, how is the earth?

Earth gives 0.1 Ohm back to the battery terminal.