Chevrolet Trax: Radio controls malfunction (color display)

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.

Diagnostic Fault Information

Circuit/System Description

The radio controls are supplied battery voltage and ground. The radio controls the power state of the controls via a wake up circuit. Communications between the radio controls and the radio are through the serial data circuits.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

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

1. Ignition ON, A11 Radio ON.
2. Verify that all radio controls operate and perform the correct function.

If some, but not all, controls operate normally.

Replace the A20 Radio/HVAC Controls.

If all controls are inoperative.

Refer to Circuit/System Testing

If all radio controls operate and perform the correct function.

3. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the A20 Radio/HVAC Controls.
2. Test for less than 10 ohms between the ground circuit terminal 3 and ground.

If 10 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

3. Test for less than 20 ohms between the shield ground circuit terminal 7 and ground.

If 20 ohms or greater

1. Ignition OFF, disconnect the X1 connector at the A11 Radio.
2. Test for less than 2 ohms in the data shield circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the A11 Radio.

If less than 20 ohms

4. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, refer to Power Mode Mismatch

If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the A20 Radio Controls.

If the test lamp illuminates.

5. Ignition ON.
6. Test for 2-3 V between the serial data circuit terminals listed below and ground.

• Terminal 4
• Terminal 8

If less than 2 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
2. Test for infinite resistance between the serial data circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the serial data circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the A11 Radio.

If greater than 3 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
2. Test for less than 1 V between the serial data circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the A11 Radio.

If between 2-3 V

7. Test for less than 1 V between the control circuit terminals listed below and ground.

• Terminal 1
• Terminal 5
• If greater than 1 V

1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
2. Test for less than 1 V between the control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the A11 Radio.

If less than 1 V

8. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
9. Test for infinite resistance between the control circuit terminals listed below and ground.

• A20 Radio/HVAC Controls terminal 1
• A20 Radio/HVAC Controls terminal 5
• If less than infinite resistance,

Repair the short to ground on the circuit.

• If infinite resistance

10. Test for less than 2 ohms between the control circuits listed below.

• A20 Radio/HVAC Controls terminal 1 and the A11 Radio terminal 13 X1
• A20 Radio/HVAC Controls terminal 5 and the A11 Radio terminal 27 X1
• If 2 ohms or greater

Repair the open/high resistance in the circuit.

If less than 2 ohms.

11. Replace the A20 Radio/HVAC Controls. Connect all harness connectors.
12. Ignition ON, radio ON.
13. Verify that all radio controls operate and perform the correct function.

If the radio controls still malfunction.

Replace the A11 Radio.

If all radio controls operate and perform the correct function.

14. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio or radio control assembly replacement, programming, and setup.

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