Faulty Internal Mode Switch
Internal Mode Switch harness is open or shorted
Internal Mode Switch circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
With the engine speed at least 500 rpm for 5 seconds, Fuel Shutoff inactive, engine torque more than 20 ft-Ibs, the Powertrain Control Module (PCM) detects that the Internal Mode Switch (IMS) ‘C’ signal was in a high state while the gear ratio indicated 1st, 2nd or 3rd gear, condition met for 0.5 seconds.