Chevy truck with no start and code U0109 in ECM for no communication with Fuel Pump Control Module (FPCM). I wish every one would be as easy as this. Found the problem the moment I looked at the FPCM. Can you figure it out from these pictures?
By the way I don’t really understand why use separate electronic module just to run the fuel pump? What was wrong with simple relay? What’s more, if this FPCM module fails it needs to be programmed with dealer scan tool. You can not just buy and plug in a new one. And failures tends to happen with electronic modules if you put them in a space like this, under the frame by the spare wheel exposed to all mud and salt and snow and rocks thrown by the wheels. FPCM module failure is very common thing but at the same time plenty of modern vehicles are doing just fine without FPCMs. Is use of FPCM provides any benefits in terms of… what? Fuel economy? Emissions? Reduced fuel pump noise? Self-diagnostic capabilities for fuel pump circuit? If I build another Chevy just like this but with simple relay controlled fuel pump circuit, would the driver feel any difference between them two? Or the benefits of FPCM are only measurable with precision instruments? Like 0.5% improvement in fuel economy or 0.1% reduced emissions.
Use of FPCM certainly provides source of income for dealers and headache for repairers. By the way, this vehicle still has fuel pump relay too, it supplies power to FPCM now. Meaning that another component added to make diagnostics more complicated and time consuming, resulting in additional repair costs for customers.