that code points to an issue with the ABS brake pressure sensor
unfortunately the sensor is not available as a service part and is inside the ABS module in the engine bay
so what is usually recommended is a replacement ABS unit which brand new can be a £1000 part
but before doing that its well worth doing a thorough bleed of all 4 corners to completly flush out the system with fresh fluid and purge it of air
I favour having a clear hose from the nipple to a jar 1/2 full of old fluid and with the nipple closed your assistant pushes the pedal up and down a few times then holds it down then you crack open the nipple and close it again whilst fluid is still flowing.
Repeat this a few times on all calipers and start with the caliper furthest away from the master cylinder.
If you still have an issue then it could be a flexible brake line is ballooning under pressure, this can't always be seen from the outside so to test this use a hose clamp on each line in turn to close off then lines one at time . Push the pedal in between and see if you can feel any difference as each line is closed off.
if none of this helps then I'd suggest getting in touch with this firm who can rebuild ABS units a lot cheaper than a new part