Here is MPPS V18 PCB wiring diagram.
U4 – PJSR05T/R TVS/ESD 5V 5A SOT-143 marking WR1
D1 – tAN
Replace L9637 chip for better k-line.
(Click on the image to enlarge it)
Thanks and reputation to the DTech666 poster on cartechnology.co.uk.
MPPS V18 clone best resource:
http://www.obd2shop.co.uk/wholesale/mpps-v18-main-tricore-multiboot.html