Theory of Operation
WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Diagnose and repair Actuator Circuit Test faults (DTC 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, and 72) before diagnosing Overcurrent faults (DTC 41, 42, 43, and 44) and Calibration faults (DTC 18, 21, 22, 23, 24, 25, 45, 46, 47, 48, 51, 52, 53, 54, 55, and 56). Diagnose and repair Overcurrent faults (DTC 41, 42, 43, and 44) before diagnosing Calibration faults (DTC 18, 21, 22, 23, 24, 25, 45, 46, 47, 48, 51, 52, 53, 54, 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 an excessive amount of commutator pulses when calibrating the left blend door, this DTC will set.
- When Monitored:
During actuator calibration.
- Set Condition:
If the A/C Heater Control detects an excessive amount of commutator pulses when calibrating the left blend door.
| Possible Causes |
|---|
| ACTUATOR CIRCUIT TEST FAULTS PRESENT |
| OVERCURRENT FAULTS PRESENT |
| LEFT BLEND DOOR OR A/C HEATER HOUSING COMPONENTS DISCONNECTED, MISSING, BROKEN |
| LEFT BLEND DOOR ACTUATOR |
| A/C HEATER CONTROL |