The engine C1731 Code has general meaning but do not use that meaning what cannot fix the car engine problem. The valves of each cylinder are kept closed using a pair of arms that replace the conventional engine’s roller-type rocker arm. C1731 code one of these arms follows the cam profile while the second arm connects to the valves. During the usual engine operation the 2 arms are linked by a locking pin. The C1731 engine code seems a sort of chassis problem and it is easy to fix the car engine problem. Once the car engine is solved, take the car for a test.