45–BLEND DOOR BOUND (MTC)





For a complete wiring diagram Refer to Section 8W.

Theory of Operation


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 no 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 no commutator pulses when calibrating the left blend door.


Possible Causes
  
ACTUATOR CIRCUIT TEST FAULTS PRESENT
  
OVERCURRENT FAULTS PRESENT
  
(C255) LEFT BLEND DOOR DRIVER CIRCUIT OPEN
  
(C55) LEFT BLEND DOOR COMMON DRIVER CIRCUIT OPEN
  
LEFT BLEND DOOR SEIZED, OBSTRUCTED
  
LEFT BLEND DOOR ACTUATOR
  
A/C HEATER CONTROL
  



Diagnostic Test

1.VERIFY IF ANY ACTUATOR CIRCUIT TEST FAULTS OR OVERCURRENT FAULTS ARE PRESENT


  • Turn the blower control on.
  • Press the A/C mode switch down, turn the blower control to off, wait until both LEDs illuminate (approximately 5 seconds) and then release the A/C mode switch.
  • When the A/C status indicator begins displaying DTCs, set the Mode switch to the floor position, simultaneously press the A/C mode switch and the EBL mode switch down until both LEDs start flashing (approximately 5 seconds) and then release the mode switches. Stored DTCs will clear from memory in approximately two seconds.


  • Turn the blower control off.
  • Press and hold the EBL mode switch down and then turn the blower control on. Continue to hold the EBL mode switch down until the EBL status indicator begins flashing. Then, release the EBL mode switch. While the test / function is running, the EBL status indicator will flash once per second. If the test / function passes, the EBL status indicator will stop flashing. If the test / function fails, the A/C and EBL status indicators will flash alternately. Allow the test / function to run to completion before proceeding.

  • Turn the blower control on.
  • Press the A/C mode switch down, turn the blower control to off, wait until both LEDs illuminate (approximately 5 seconds) and then release the A/C mode switch.

NOTE: The A/C status indicator displays active DTCs when the EBL status indicator is not illuminated and stored DTCs when the EBL status indicator is illuminated.




Does the A/C status indicator display any of the following DTCs: 41, 42, 43, 44, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, or 72?

Yes
  • As present, diagnose and repair the faults in the following order: DTC 72 first, then DTC 62, then DTC 61, then DTCs 64, 66, 68, or 71, then DTCs 63, 65, 67, or 69, and finally DTCs 41, 42, 43, or 44. Refer to the Table Of Contents in this section for a complete list of HVAC related symptoms.


No
  • Go To 2

2.CHECK THE LEFT BLEND DOOR ACTUATOR CIRCUIT RESISTANCE







Is the resistance above 70.0 ohms?

Yes
  • Go To 3


No
  • Go To 5

3.CHECK THE (C255) LEFT BLEND DOOR DRIVER CIRCUIT FOR AN OPEN






Is the resistance below 5.0 ohms?

Yes
  • Go To 4


No

4.CHECK THE (C55) LEFT BLEND DOOR COMMON DRIVER CIRCUIT FOR AN OPEN





Is the resistance below 5.0 ohms?

Yes


No

5.INSPECT ACTUATOR & HOUSING ASSEMBLY FOR A CONDITION CAUSING THE LEFT BLEND DOOR TO SEIZE




Are there any physical or mechanical problems with the door, housing, linkage, or actuator?

Yes


No
  • Go To 6

6.CHECK LEFT BLEND DOOR TRAVEL




Does the door operate smoothly in both directions over the entire span of travel?

Yes
  • Replace the Left Blend Door Actuator in accordance with the Service Information. Then, Go To 7.


No

7.VERIFY IF THE FAULT IS STILL PRESENT


  • Turn the blower control on.
  • Press the A/C mode switch down, turn the blower control to off, wait until both LEDs illuminate (approximately 5 seconds) and then release the A/C mode switch.
  • When the A/C status indicator begins displaying DTCs, set the Mode switch to the floor position, simultaneously press the A/C mode switch and the EBL mode switch down until both LEDs start flashing (approximately 5 seconds) and then release the mode switches. Stored DTCs will clear from memory in approximately two seconds.


  • Turn the blower control off.
  • Press and hold the EBL mode switch down and then turn the blower control on. Continue to hold the EBL mode switch down until the EBL status indicator begins flashing. Then, release the EBL mode switch. While the test / function is running, the EBL status indicator will flash once per second. If the test / function passes, the EBL status indicator will stop flashing. If the test / function fails, the A/C and EBL status indicators will flash alternately. Allow the test / function to run to completion before proceeding.

  • Turn the blower control on.
  • Press the A/C mode switch down, turn the blower control to off, wait until both LEDs illuminate (approximately 5 seconds) and then release the A/C mode switch.

NOTE: The A/C status indicator displays active DTCs when the EBL status indicator is not illuminated and stored DTCs when the EBL status indicator is illuminated.




Does the A/C status indicator display DTC 45?

Yes


No