2006 Buick Rendezvous Q&A
2006 Buick Rendezvous Question: what is po641 error code for above vehicle?
It means you have a 5v reference circuit problem from the PCM. Ref cir #1 feeds the fuel tanK pressure sensor and the EGR. #2 feeds the MAP sensor and the a/c refrigerant pressure sensor. They send a 5v sig to each and the return voltage tells the computer how it is working or not working. See a tech to trace the circuit and repair it. - ProfessorG
agree with #1 - globalhelper