Circuit Description

To determine engine oil life remaining, PCM monitors engine coolant temperature, number of crankshaft revolutions, vehicle speed, engine speed, and calculated oil temperature. When PCM determines engine oil is near end of its useful life, it will command instrument cluster via serial data circuit to illuminate CHANGE OIL SOON indicator or CHANGE OIL SOON/NOW message after start-up. PCM will command CHANGE OIL SOON indicator or CHANGE OIL SOON/NOW message on after each start-up until engine oil life monitor is reset by grounding oil life monitor reset input circuit through oil life monitor reset switch for more than 5 seconds.

P1619 does not illuminate Malfunction Indicator Light (MIL).