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Home >> Chevrolet >> 2011 >> Volt >> Repair and Diagnosis >> External Pages >> Different car >> Section 20 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> Radio Controls Malfunction >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2012 Chevrolet Volt. However, it is still accessible from the selected car via links, so may be relevant.
  1. Vehicle OFF, disconnect the harness connector at the A20 radio/HVAC controls.
  2. Test for less than 10 Ω between the ground circuit terminal 17 and ground.
    • If 10 Ω or greater 
    1. Vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Test for less than 20 Ω between the data shield circuit terminal 3 and ground.
    • If 20 Ω or greater 
    1. Vehicle OFF, disconnect the X1 connector at the A11 radio.
    2. Test for less than 2 Ω in the data shield circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the A11 radio.
    • If less than 20 Ω 
  4. Verify that a test lamp illuminates between the B+ circuit terminal 10 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Vehicle OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, refer to Power Mode Mismatch .
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Vehicle 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/HVAC controls.
    • If the test lamp illuminates. 
  5. Vehicle in Service Mode.
  6. Test for 2-3 V between the serial data circuit terminals listed below and ground.
    • terminal 1
    • terminal 2
    • If less than 2 V 
    1. Vehicle 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 Ω in the serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the A11 radio.
    • If greater than 3 V 
    1. Vehicle OFF, disconnect the X1 harness connector at the A11 radio. Vehicle in Service Mode.
    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 4
    • terminal 15
    • If greater than 1 V 
    1. Vehicle OFF, disconnect the X1 harness connector at the A11 radio. Vehicle in Service Mode.
    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. Vehicle 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 4
    • A20 radio/HVAC controls terminal 15
    • If less than infinite resistance, 

      Repair the short to ground on the circuit.

    • If infinite resistance 
  10. Test for less than 2 Ω between the control circuits listed below.
    • A20 radio/HVAC controls terminal 4 and the A11 radio terminal 13 X1
    • A20 radio/HVAC controls terminal 15 and the A11 radio terminal 27 X1
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • If less than 2 Ω. 
  11. Replace the A20 radio/HVAC controls. Connect all harness connectors.
  12. Vehicle in Service Mode, 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
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