DTC B1020
Diagnostic Instructions
DTC Descriptor
DTC B1020 00: Auxiliary Electronic Control Unit (ECU) Performance
Circuit/System Description
The radio communicates with the radio/HVAC control via serial data. This DTC indicates a fault in the radio/HVAC control. No external circuits are involved. The radio may continue to respond normally to faceplate functions when this DTC is set.
Conditions for Running the DTC
| • | Ignition is ON or in the ACC position. |
| • | The system voltage is at least 9.5 V and no more than 15.5 V. |
| • | All the above conditions are present for greater than 10 seconds. |
Conditions for Setting the DTC
The radio receives an improper status response indicating an internal ECU fault in the radio/HVAC control.
Action Taken when the DTC Sets
No action is taken.
Conditions for Clearing the DTC
| • | A current DTC clears when the radio receives a proper status response message back from the radio control assembly. |
| • | A history DTC clears after 50 malfunction-free ignition cycles. |
Diagnostic Aids
| • | This DTC may be stored as a history DTC without affecting the operation of the radio/HVAC control. |
| • | If stored only as a history DTC and not retrieved as a current DTC, do not replace the radio/HVAC control. |
| • | If this DTC is retrieved as both a current and history DTC, replace the radio/HVAC control. |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
If this DTC is retrieved as a current DTC, replace the A20 radio/HVAC control.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for radio/HVAC control replacement, setup, and programming
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