Conditions for Clearing the DTC

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The DTC will become history if the HVAC Module no longer detects a failure.
The history DTC will clear after 50 fault free ignition cycles.
The DTC can be cleared with a scan tool.

DTC B1020

Step	Action	Yes	No
Schematic Reference: HVAC Schematics
1	Did you perform the HVAC Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - HVAC Systems - Automatic
2	Use the scan tool to clear the DTCs. Turn OFF the ignition and wait 45 seconds. Turn ON the ignition with the engine OFF. Select the HVAC DTC display function on the scan tool. Does the scan tool display DTC B1020?	Go to Step 3	Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS
3	Test the auxiliary mode door control circuit between the front auxiliary control module and the rear auxiliary control module for a short to voltage. Refer to TESTING FOR A SHORT TO VOLTAGE . Did you find and correct the condition?	Go to Step 6	Go to Step 4
4	Test the auxiliary temperature door control circuit between the front auxiliary control module and the rear auxiliary control module for a short to voltage. Refer to TESTING FOR A SHORT TO VOLTAGE . Did you find and correct the condition?	Go to Step 6	Go to Step 5
5	Replace the Rear Aux (ECC ) control module. Refer to HVAC Control Module Replacement - Auxiliary . Is the repair complete?	Go to Step 6	-
6	Use the scan tool in order to clear the DTCs Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	Go to Step 2	System OK