help needed ecu code 53
 

as above engine check light came on for about 10 seconds earlier so did blink test and came up code 22 knock sensor (poss cos mrs put w@nk fuel in), and code 53? it lists quite a few for it on net.
53 Antenna
53 Anti-Quick Operation Mode
53 Communication Error (Time Over)
53 EGI Control Module EEPROM
53 IMM Circuit Failure (Except Antenna Circuit)
53 IMM Control Module EEPROM
53 Key Communication Failure
53 Reference Code Incompatibility
53 Use of Unregistered Key
where do i start? car is a my97 uk 2000
any help appreciated.

also found on another site code 53 means fuel pump circuit, which could be the fact as the mrs nearly ran it out of fuel before filled up and said it juddered on a round about which would cause both fault codes to come on.