Hi guys,

My car S80 2007 doesn’t start as no fuel reach engine!!

Problem happened one month ago, I changed the fuel pressure sensor and fuel pump.

Again, same problem happened 4 days ago (3 weeks after replacing the fuel pressure sensor and Fuel Pump).

I noticed that, no signal comes to the fuel pump and once the engine starts the car is running perfect!!

Finding; when I press the brake pad and push start bottom, no electrical signal come to the fuel pump!!

Action I did:

- I removed the fuel tank and check the fuel pump separately it’s ok! And wire all is OK!!

- I passed the pump electronic module through a hole under the back seat and kept the module under the seat for easy access if it needs to change.

- Car starts immediately with no problem and runs perfectly even the acceleration is ok (why not the problem was engine start only)

- I put into the tank “Fuel system cleaner fluid” to clean injectors and remove any clogs.

Conclusion;

1- When I press the brake pad, no electrical signal is delivered, or

2- On starting the car PEM sometimes delivers signal to Pump and sometimes doesn’t deliver signal to pump.

Question:

1- Do I need to replace the PEM or

2- Is the problem with the wire coming from the brake to PEM or

3- Another mechanical issue?

I highly appreciate your valuable advice.