Check the reasons Engine Oil Temperature Sensor Malfunction, Ignition/Distributor Engine Speed Input Circuit Malfunction and Clutch Position Sensor Circuit Malfunction to know the problem of the engine C1873 Code. The engine problem is triggered by the adjustable cylinder running system switching on and off throughout light throttle conditions, at sailing speeds, or when driving on level roads. The continuous switching causes extreme oil feasting and the trouble codes appear when oil compression drops to the fact where it can no longer function the VCM system. Do not drive the car without fixing the problem. The minor problem from the car engine can be a cause of fetal problem.