I have two CAT 420D machines exhibiting the same issue: When I turn the key switch off, both continue to run-on at a slow RPM. To kill the engine, I either have to actuate a hydraulic valve or turn the key back on. A local electrician told me it is either a dirty/defective solenoid that kills the engine or a defective key switch. As a rule, I will trust Satan before I trust electricians in this country. Because I have to ship all parts to Liberia from the U.S., I want to be certain the cause before shipping replacement parts. Even better, it would be great if I can fix it myself on this side of the pond! Any thought? Eric
BTW, if it helps, here are the PIN #'s for my backhoes: CAT 416D – PIN # CAT0416DABFP14642 CAT 420D – PIN # CAT0420DAFDP26886 CAT 420D – PIN # CAT0420DCFDP23847 Thanks!
Can you try un-hooking the wire that goes to the shutoff solenoid and see if it dies then, if it does then take a voltage meter if you have one and see if you still have power on the wire that goes to the shutoff solenoid when the key is off.
kbeen- Thanks for the advice. I will check that out and get back with you. BTW, where are you at in OK? My backhoes shipped from Fairview.
I am approx. 150 miles east and south of fairview.