Blend Door Travel Range Too Large (MTC)

B1051-BLEND DOOR TRAVEL RANGE TOO LARGE (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 exceeds 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 Front Blend Door exceeds the high 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.CHECK FOR A BROKEN FRONT BLEND DOOR ACTUATOR

Turn the ignition off.

Remove the Front Blend Door Actuator from the A/C Heater Housing Assembly.

By hand, attempt to rotate the actuator in both directions.

Does the actuator turn in either direction?

Yes

- Replace the Front Blend Door Actuator.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 4

4.CHECK FRONT BLEND DOOR & A/C HEATER HOUSING FOR WARPED, WORN, DAMAGED, MISSING, & BROKEN COMPONENTS

Inspect for excessively worn, disconnected, missing, or broken door linkage. Inspect for a damaged or broken A/C Heater Housing Assembly. Inspect for a warped or broken door, and missing door seals. Rotate the door from stop to stop. The door should rotate approximately 65 degrees.

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

Yes

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

No

- Replace the Front Blend Door Actuator. Then, Go To 5.

5.RUN 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: B1051-BLEND DOOR TRAVEL RANGE TOO LARGE?

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