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DTC B1020

DTC B1020

Diagnostic Instructions


Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptor

DTC B1020 00

Auxiliary Electronic Control Unit Malfunction

Circuit/System Description

The navigation radio communicates with the radio display assembly via serial data. If the radio receives an improper status response message, DTC B1020 will set.

This DTC indicates an fault in the display. No external circuits are involved.

Conditions for Running the DTC


Ignition is ON or in the ACCESSORY position.

The system voltage is between 9.5-15.5 V.

All the above conditions are present for greater than 10 s.


Conditions for Setting the DTC

The radio receives an improper status response indicating an internal electronic control unit fault or a stuck button in the radio display assembly.

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 will clear after 50 malfunction-free ignition cycles.


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


Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Verify that DTC B1020 is not set.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.