GM Service Manual Online
For 1990-2009 cars only

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 Descriptors

DTC B3622 01: Steering Wheel Controls Signal Circuit Short to Battery

DTC B3622 08: Steering Wheel Controls Signal Circuit Signal Invalid

DTC B3622 59: Steering Wheel Controls Signal Circuit Protection Timed Out

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+ Voltage Reference

1

1

--

--

Steering Wheel Controls Signal Circuit

1

1

B3622 01

B3622 58, B3622 08

1. Steering Wheel Controls Inoperative

Circuit/System Description

The instrument panel module (IPM) supplies voltage to the multiple 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 that switch. The IPM identifies the selection, then sends a serial data message that is received by the component controlled, activating the feature. If equipped with adaptive cruise control the Gap+/Gap- switches are in place of the mute/source switches and are in the same resistor ladder circuit.

Conditions for Running the DTC

    • Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.
    • IPM in Accessory, Run or Crank power modes.

Conditions for Setting the DTC

B3622 01

The IPM detects a short to voltage on steering wheel controls signal circuit, for more than 5 seconds.

B3622 08

The IPM detected the signal from the steering wheel controls signal circuit does not fall into a calibrated range.

B3622 59

The IPM detects that any of the steering wheel control switches is stuck, for more than 30 seconds.

Action Taken When the DTC Sets

B3622 01 and 08

The IPM does not react to any switch inputs.

B3622 59

The IPM does not react to any switch inputs of equal or lower priority. If 2 switches are closed at the same time the IPM will read the least resistive path, so that switch takes precedence over the other one.

Conditions for Clearing the DTC

    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

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

Component Connector End Views

Description and Operation

Steering Wheel Controls 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

Ignition ON, observe the scan tool steering wheel controls return while pressing the steering wheel control switch. The reading should change with each switch pressed and display counts when inactive.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
  2. Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground.
  3. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
  4. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminals listed below:
  5. • Left switch terminal 6
    • Right switch terminal 2
    If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
  6. Ignition OFF, disconnect the X3 harness connector at the IPM.
  7. Test for infinite resistance between the signal circuit terminal 18 and ground.
  8. If less than the specified value, test the signal circuit for a short to ground.
  9. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch.
  10. If greater than the specified range, test the voltage reference circuit for a short to voltage
  11. Ignition OFF, test for infinite resistance between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch.
  12. If not the specified value, test the voltage reference circuit for a short to ground.
  13. Ignition ON, test for less than B+ between the ground circuit terminal 4 at the left steering wheel control switch and the voltage reference circuit terminal 1 at the right steering wheel control switch.
  14. If less than the specified range, test the voltage reference circuit for a an open/high resistance.
  15. If all circuits test normal, test or replace the left or right steering wheel control switch.

Component Testing

  1. Disconnect the harness connector at the right or left steering wheel control switch.
  2. Connect a DMM between terminals 1 and 2 of either the left or right steering wheel control switch.
  3. If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the right steering wheel control switch.

Left Steering Wheel Switch Resistance

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Mute/Voice Recognition

1.8k Ohms

2.2k Ohms

Previous/Gap Up

3.4k Ohms

3.8k Ohms

Next/Gap Down

6.5k Ohms

6.9k Ohms

Source

7.7k Ohms

8.1k Ohms

No Switch Pressed

O.L.

O.L.


Right Steering Wheel Switch Resistance

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Scan

1.1k Ohms

1.3k Ohms

Seek

1.4k Ohms

1.8k Ohms

Volume Down

1.7k Ohms

2.1k Ohms

Volume Up

2.2k Ohms

2.6k Ohms

No Switch Pressed

O.L.

O.L.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Steering Wheel Control Switch Assembly Replacement
    •  Control Module References for IPM replacement, setup, and programming