so if the sensor is bad , will the ecm still adjust thee timing? I have the same issue with a P0335 and a P1336 code. the engine still seems to run properly but I wont be able to get it smoged .does the Tachometer run off of the Crank sensor, my tach still functions. I had the heads off and reconed and changed the sensor when I get to it easily then 350 miles later , it is throwing codesOn a VQ or a QR engine, a bad crank sensor can cause a no start, but the crank sensor mounted on the transmission bellhousing on a VG33E engine is only a monitoring sensor for the ECM to reference. It can't cause a no start condition or any other drivability concern if it fails.