P0231 - on a Ford Expedition 2003

Question

What could be causing this code and also another code "on board diagnostics 2 monitor drive cycle test not complete" on a 2003 Ford Expedition Eddie bauer

Answer 1

P0231 Low voltage fuel pump secondary circuit

When the circuit is low for the fuel pump relay you can expect the relay to not operate as it is intended. The fuel pump relay is soldered onto the PDJB so the board will need to be replaced , (unless you can rebuild it which will require soldering to remove the fuel pump relay) , As long as there is a code whether it is pending or set the monitor will not set.