Notes On Intermittents
If intermittent code EO20 is stored, unplug oil pressure switch. Start engine, allow it to idle, and manipulate affected wiring. Ensure that ECM connectors are properly latched and check relay for proper installation into relay center socket. If fault is induced, the engine will stall, and code EO20 will set. If code EO20 sets without an engine stall, cause is an intermittent open in circuit No. 120A between ECM pin "D9" and splice on circuit No. 120B.
Review snapshot data parameters stored with this code to verify failure. If failure is verified, check and repair intermittent wiring connection or sensor.