Unusual, as it sounds like an immobiliser issue which would normally log fault codes. What is the key warning lamp on the dash doing?
Keys are common for failing, one stops working, then the other!
The ecu is in the passenger footwell. Lift the carpet up and check for water ingress (blocked sunroof drains) or wiring loom rubbed against ecu bracket.
I have come across shorted injectors but they again would log a code.

What are you using to interrogate this? Sounds bizarre but if it's a Delphi Autocom unit go in as a Hyundai H100 van with 2.5 diesel engine

Tony