Hi,
My friend have a Hummer H2 SUT year 2008 6,2i engine.
Monday evening when he wanted to go home with his Hummer the car not start.The last start was two hours before.
I go to him...i connected my OBD-II ELM 327 diagnosis and I haved this error:NO COMMUNICATION WITH FUEL PUMP and the pressure was 0 bar.
I get out the OBD plug and tryed to start again.The car started with no problem.I repluged the OBD ELM and the fuel presure was 4 bar.
When he arrived home ,he shut off the engine,and tryed to start again.The engine not start and this time is the same error and the car not start.

What to verify?What to do?

.I am sorry for my bad English ,i am from Romania,and i don't know so good.Thank you.

 

Solved.Bad wire contact...