GM Service Manual Online
For 1990-2009 cars only

DTC B3608 4-spoke

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 B3608 01: Steering Wheel Control Entertainment Output Signal Circuit Short to Battery

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

10-Volt Reference

1

1

1

--

Steering Wheel Control Signal

1

1

B3608

--

1. Steering Wheel Controls Inoperative

Circuit/System Description

The radio supplies 10 volts to the steering wheel control momentary contact switches, and monitors the return signal. Each switch is associated to a set resistance value, when pressed a specific voltage drop occurs through a series of resistors unique to the switch selected. The radio will perform the desired function, or send a serial data message to its another component.

Conditions for Running the DTC

    • The radio is in the ACCESSORY, RUN, or RAP power mode.
    • The system voltage is at least 9 volts and no more than 16 volts.
    • All the above conditions are present for greater than 50 ms.

Conditions for Setting the DTC

Short to voltage is present for 50 ms or longer.

Action Taken When the DTC Sets

The steering wheel control switch functions are inoperative.

Conditions for Clearing the DTC

    • The conditions for setting the DTC are no longer present.
    • A history DTC clears after 100 malfunction-free ignition cycles.
    • The radio receives the clear code command from the scan tool.

Diagnostic Aids

Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.

Reference Information

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

    •  Entertainment/Communication Connector End Views
    •  Secondary/Configurable Control Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.

Caution: Refer to SIR Caution in the Preface section.

  1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
  2. Ignition ON, Radio ON, test for 9.2-10 volts between the 10-volt reference circuit terminal and ground.
  3. If less than the specified range, test the 10-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    If greater than the specified range, test the 10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the radio.
  4. Test for 9.2-10 volts between the 10-volt reference circuit terminal and the signal circuit terminal 4.
  5. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the radio.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  6. Connect a 3A fused jumper wire between the 10-volt reference circuit terminal 1 and the signal circuit terminal 5.
  7. Disconnect the harness connector at the left steering wheel control switch.
  8. Test for 9.2-10 volts between the signal circuit terminal 1 and ground.
  9. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  10. Test for 9.2-10 volts between the signal circuit terminal and the signal circuit terminal 4.
  11. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the radio.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  12. Disconnect the C1 harness connector at the radio.
  13. Test for infinite resistance between the signal circuit terminal A9 and ground.
  14. If not the specified value, test the signal circuit for short to ground.
  15. If all circuits test normal, test or replace the steering wheel control switch.

Component Testing

Caution: Refer to SIR Caution in the Preface section.

  1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
  2. Test for less the 2,400 ohms of resistance between the signal circuit terminal 5 and the 10-volt reference terminal 1.
  3. If greater than the specified range, replace the right steering wheel control switch.
  4. Test for infinite resistance between the signal circuit terminal 4 and the 10-volt reference terminal 1 with the switch in the open position.
  5. If not the specified value, replace the right steering wheel control switch.
  6. Test for less than 2,400 ohms of resistance between the signal circuit terminal 4 and the 10-volt reference terminal with the switch in the closed position.
  7. If greater than the specified value, replace the right steering wheel control switch.
  8. Disconnect the harness connector at the left steering wheel control switch.
  9. Test for infinite resistance between the signal circuit terminal 4 and the signal circuit terminal 1 with the switch in the open position.
  10. If not the specified value, replace the left steering wheel control switch.
  11. Test for less than 12,000 ohms of resistance between the signal circuit terminal 4 and the signal circuit terminal with the switch in the closed position.
  12. If greater than the specified value, replace the left steering wheel control switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Radio replacement, setup, and programming

DTC B3608 3-Spoke

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 B3608 01: Steering Wheel Control Entertainment Output Signal Circuit Short to Battery

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

10-Volt Reference

1

1

1

--

Steering Wheel Control Signal

1

1

B3608

--

1. Steering Wheel Controls Inoperative

Circuit/System Description

The radio supplies 10 volts to the steering wheel control momentary contact switches, and monitors the return signal. Each switch is associated to a set resistance value, when pressed a specific voltage drop occurs through a series of resistors unique to the switch selected. The radio will perform the desired function, or send a serial data message to its another component.

Conditions for Running the DTC

    • The radio is in the ACCESSORY, RUN, or RAP power mode.
    • The system voltage is at least 9 volts and no more than 16 volts.
    • All the above conditions are present for greater than 50 ms.

Conditions for Setting the DTC

Short to voltage is present for 50 ms or longer.

Action Taken When the DTC Sets

The steering wheel control switch functions are inoperative.

Conditions for Clearing the DTC

    • The conditions for setting the DTC are no longer present.
    • A history DTC clears after 100 malfunction-free ignition cycles.
    • The radio receives the clear code command from the scan tool.

Diagnostic Aids

Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.

Reference Information

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

    •  Entertainment/Communication Connector End Views
    •  Secondary/Configurable Control Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Testing

Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.

Caution: Refer to SIR Caution in the Preface section.

  1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
  2. Ignition ON, Radio ON, test for 9.2-10 volts between the 10-volt reference circuit terminal 2 and ground.
  3. If less than the specified range, test the 10-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    If greater than the specified range, test the 10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the radio.
  4. Test for 9.2-10 volts between the 10-volt reference circuit terminal 2 and the signal circuit terminal 4.
  5. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the radio.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  6. Disconnect the C1 harness connector at the radio.
  7. Test for infinite resistance between the signal circuit terminal A9 and ground.
  8. If not the specified value, test the signal circuit for short to ground.
  9. If all circuits test normal, test or replace the steering wheel control switch.

Component Testing

Caution: Refer to SIR Caution in the Preface section.

  1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
  2. Test for infinite resistance between the signal circuit terminal 4 and the 10-volt reference terminal 2 with the switch in the open position.
  3. If not the specified value, replace the right steering wheel control switch.
  4. Test for less than 3,200 ohms of resistance between the signal circuit terminal 4 and the 10-volt reference terminal 2 with the switch in the closed position.
  5. If greater than the specified value, replace the right steering wheel control switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for radio replacement, setup, and programming