We had this issue last spring . This service engine soon light would stay on and bus would lose power . So during Summer I went into the fuel system and found the lift pump was crap . So I changed the lift pump out and light stayed away and bus had lots of power . Last week the driver of this bus came to me and said the light would come on sometimes . When it did loss of power . So tonight I drove her bus on a run . Went to pre trip light came on . Start of the route light came on for few seconds and went off . Did this about 6 or 7 times then stayed off .Could there be a sensor that went bad when the lift pump was bad ? Or maybe with such low pressure it damaged the injector pump ? Do I need a Cummins program to tell me what might be wrong ? I know I have been told I need this program from Cummins by people on this forum . Maybe I need to follow this advice . My other question is the last 2 buses we purchased have Cummins and wondered if they all take the same program ? Thanks
Cannot guarantee anything, but we have changed many, many, many engine speed sensors on these. Always an engine light and low power. We put the scan tool on and get the code, which I don't recall at the moment. A real treat, located behind the starter. P/N for ours is 4921601
04 5.9 Cummins service engine soon light
Posted - 10/09/2017 : 8:38:09 PM
