Theory Of Operation
Note. Diagnose and repair Actuator Circuit Test faults (DTC 61, 62, 63, 64, 67, 68, 69, 71, and 72) before diagnosing Overcurrent faults (DTC 41, 43, and 44) and Calibration faults (DTC 18, 21, 22, 23, 45, 46, 47, 51, 52, 53, 55, and 56). Diagnose and repair Overcurrent faults (DTC 41, 43, and 44) before diagnosing Calibration faults (DTC 18, 21, 22, 23, 45, 46, 47, 51, 52, 53, 55, and 56).
The purpose of actuator calibration is to determine the total span of door travel between physical stops. To calibrate the actuator, the A/C Heater Control first moves the door to its soft stop, and then counts the number of pulses it takes to move the door to its other stop. An expected range of span is stored in the control's memory. If the A/C Heater Control detects too few commutator pulses when calibrating the left blend door, this DTC will set.