I have a 03 ford mondeo with a faulty PATS immobiliser where the engine won't crank. Can I swap in a 2nd hand ecu with keys to fix it?

I have a 03 ford mondeo with a faulty PATS immobiliser where the engine won't crank. Can I swap in a 2nd hand ecu with keys to fix it? - 1

Check for a bad ECU ground first. No joy, swap the ECU.

Immobilizers don't keep a vehicle from cranking over. They shut off the fuel pump or injectors.