Floor/Defrost Mode Door Travel Range Too Small (MTC)

B104A-FLOOR/DEFROST MODE DOOR TRAVEL RANGE TOO SMALL (MTC)

For a complete wiring diagram refer to Diagrams/Electrical.

Theory of Operation

The A/C Heater Control calibrates each actuator individually. Automatic calibration occurs upon power up after installing a new A/C Heater Control. Manual calibration occurs by sending a command with the scan tool. 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 measured calibration value is less than the expected range for this actuator, this DTC will set. Note that the control clears all stored calibration faults at the beginning of the calibration procedure.

- When Monitored:

During actuator calibration.

- Set Condition:

If the total span of the Mode 2 (Floor to Defrost) Door is less than the low range limit.





Diagnostic Test

1.CHECK FOR ACTIVE CONTROL CIRCUIT/PERFORMANCE & CONTROL CIRCUIT OPEN DTCs

Turn the ignition on.

With the scan tool, read active HVAC DTCs.

Does the scan tool display any active: XXXX CONTROL CIRCUIT/PERFORMANCE or XXXX CONTROL CIRCUIT OPEN DTCs?

Yes

- Diagnose and repair the DTC(s).

No

- Go To 2

2.RUN THE ACTUATOR DTC DETECTION TEST

With the scan tool in HVAC, select System Tests and then select Actuator DTC Detection. When the test is complete, select View DTCs.

Does the scan tool display any DTCs?

Yes

- Diagnose and repair the DTC(s). If multiple DTCs are present, beginning with the common circuits, diagnose and repair all short high DTCs first, all short low DTCs second, and all open DTCs last.

No

- Go To 3

3.INSPECT ACTUATOR & HOUSING ASSEMBLY FOR A CONDITION CAUSING THE DOOR TO SEIZE OR BIND

Turn the ignition off.

Inspect the actuator, linkage, and housing assembly for a condition causing the door to seize or bind.

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

Yes

- Repair as necessary.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 4

4.CHECK MODE 2 (FLOOR TO DEFROST) DOOR TRAVEL

Remove the Mode Door 2 (Floor to Defrost) Actuator from the A/C Heater Housing Assembly.

By hand, attempt to rotate the door in both directions. The door should operate smoothly in both directions over approximately 100 degrees.

Does the door operate smoothly in both directions over approximately 100 degrees of travel?

Yes

- Replace the Mode Door 2 (Floor to Defrost) Actuator. Then, Go To 5.

No

- Repair as necessary.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

5.RUN THE ACTUATOR CALIBRATION TEST

Turn the ignition on.

With the scan tool, select System Tests and then select Actuator Calibration Test. When the test is complete, select View DTCs.

Does the scan tool display: B104A-FLOOR/DEFROST MODE DOOR TRAVEL RANGE TOO SMALL?

Yes

- Replace the A/C Heater Control.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test