Manual Temperature Control

B1057 - Rear Blend Door Travel Range Too Large

For a complete wiring diagram, refer to.

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 rear blend door exceeds the high range limit.






Test Step 1 - Check for an Active Control Circuit/Performance and Control Circuit Open DTCs

• Turn the ignition ON.

• With the scan tool, read active HVAC DTCs.

Does the scan tool display any active control circuit/performance or control circuit open DTCs?

Yes

• Diagnose and repair the DTCs. Refer to the table of contents in this section for a complete list of all HVAC related symptoms.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Go to Test Step 2 => [ Test Step 2 - Check for a Broken Rear Blend Door Actuator ]

Test Step 2 - Check for a Broken Rear Blend Door Actuator

• Turn the ignition OFF.

• Remove the rear blend door actuator from the rear 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 rear blend door actuator.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Go to Test Step 3 => [ Test Step 3 - Check Rear Blend Door and Rear A/C Heater Housing For
Warped, Worn, Damaged, Missing, and Broken Components ]

Test Step 3 - Check Rear Blend Door and Rear A/C Heater Housing For Warped, Worn, Damaged, Missing, and Broken Components

• Inspect for a damaged or broken Rear A/C Heater Housing Assembly, a warped, worn, or broken door, and missing door seals. Rotate the door from stop to stop. The door should rotate approximately 70 degrees.

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

Yes

• Repair as necessary.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Replace the rear blend door actuator.Then, Go To Test Step 4 => [ Test Step 4 - Run the Actuator Calibration Test ]

Test Step 4 - 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 this DTC as active?

Yes

• Replace the A/C heater control.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test