Re the heater plugs, I would check what it says about the heater plug relay first. I have always tried to test to be sure, most modern systems have a separate feed to each heater plug from the relay so you can test individually, some people just use a Ohm meter, but personally these days once I know the operating voltage of that type of heater plug (some are only 4.4 volts) I use a power supply and a good amp meter in circuit, often the reading of a good heater plug will be around 11 amps, but only test for a short time to prevent damage.
This was online and may be worth checking:-
"The diagnostic trouble code (DTC) P1541 has multiple possible meanings depending on the vehicle's make and model, including a fault with the variable displacement oil pump (common in Alfa Romeo and Fiat) an open fuel fuel pump relay circuit"