Fault Conditions

ECM-644A is stored in ECM if camshaft is not in correct position. ECM registers this as a fault as soon as engine is started. ECM registers a fault and ECM-644A is stored in ECM if camshaft position sensor flanker is not correct in relation to RPM sensor. ECM registers a fault and ECM-644A is stored in ECM if camshaft does not rotate quickly enough in response to control signal.

No substitute value is used. Variable camshaft timing is disabled while ECM-644A is set. Idle may be uneven.