2012 LExus IS350 AWD high pressure fuel pump issues

drakexha

hi i have had absolutely no trouble with my car until the other day. I drove it to work just fine, but when I came back at lunch it had the check engine light on. I drove it around the parking lot...it wouldn't go above 20mph. Dealership said the high pressure fuel pump is bad. my car only has 75,000 miles on it. I use the high quality gas every time. I get oil changes regularly. I've have not heard any funny noises-no problems starting the car. How do mechanics check to be sure it really is the fuel pump? I had a recall issue fixed about 4 months ago-the fuel delivery pipe was replaced. Does that have anything to do with the fuel pump?

thecardoc3

The short answer is they have to first confirm that the supply side of the system is working correctly. Then confirm that the engine controller is commanding the fuel regulator solenoid to direct fuel to the high pressure fuel rail. All while monitoring scan data to see if the reported high side pressure meets desired pressure or not. There are scan tool bi-directional commands that allow techs to command the fuel rail pressure to change for testing purposes that help with the testing. In the end once everything external is ruled out and the pump itself is the only possibility left you have the diagnosis.