Fuel pump works when 12v applied. So start there and work back.
When ignition is first turned on the pump should run for a few seconds to pressurise the system.
Put a test meter at the pump feed and turn the ignition on. Pump should run, but we know it doesn't, so is there a feed.
If there is, follow the earth path and fix it.
If no feed, go back to the relay output and check there.
If no relay output, two things to check, relay input, and relay switching.
To chase back to the ECU we'd need to know the pin number that outputs the switching signal. Workshop manual needed.
Report back.
When ignition is first turned on the pump should run for a few seconds to pressurise the system.
Put a test meter at the pump feed and turn the ignition on. Pump should run, but we know it doesn't, so is there a feed.
If there is, follow the earth path and fix it.
If no feed, go back to the relay output and check there.
If no relay output, two things to check, relay input, and relay switching.
To chase back to the ECU we'd need to know the pin number that outputs the switching signal. Workshop manual needed.
Report back.