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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 Montana SV6 Ext. 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 OnStar Button Malfunction

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

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Keypad Supply Voltage

B2476 00

B2476 00

B2476 00

--

Keypad Green LED Signal

1

1

2

--

Keypad Red LED Signal

1

1

2

--

Keypad Signal

3

3

--

B2482 00

Button Assembly Ground

--

1

--

--

1. OnStar® LED(s) Inoperative

2. LED illuminated at all times

3. OnStar® Buttons Inoperative

Circuit/System Description

The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center, and OnStar® Emergency. The communication interface module (CIM) supplies the OnStar® button assembly with 10 volts via the keypad supply voltage circuit. Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the CIM over the keypad signal circuit. Depending upon the voltage range returned, the CIM is able to identify which button has been activated.

Reference Information

Schematic Reference

OnStar Schematics

Connector End View Reference

Component Connector End Views

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

Important: Contact the OnStar® Call Center first before pressing the emergency button in order to notify them of the test.

Ignition ON, press the OnStar® Call buttons one at the time. Verify that all of the OnStar® buttons operate normally.

⇒If some OnStar® buttons are inoperative but not all, replace the inside rearview mirror.
⇒If none of the OnStar® buttons operate, refer to circuit/system testing.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the OnStar® button assembly.
  2. Test for less than 10 Ω between the button assembly ground circuit terminal E and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, test for less than 1 V between the keypad signal circuit terminal B and ground.
    4. ⇒If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the CIM.
  4. Ignition OFF, test for 600 K - 800 K Ω between the keypad signal circuit terminal B and ground.
    5. ⇒If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit tests normal, replace the CIM.
    ⇒If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the CIM.
  5. Ignition ON, test for 9.5-10.5 V between the keypad supply voltage circuit terminal A and ground.
    6. ⇒If less than the specified range, test the supply voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the CIM.
    ⇒If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the CIM.
  6. If all circuits test normal, test or replace the button assembly.

Component Testing
  1. Ignition OFF, disconnect the harness connector at the button assembly.
  2. Test for infinite resistance between the keypad supply voltage terminal A and the keypad signal terminal B.
    3. ⇒If less than the specified range, replace the button assembly.
  3. Test for 1.4 K - 1.6 K Ω between the keypad supply voltage terminal A and the keypad signal terminal B while pressing the black phone button.
    4. ⇒If not within the specified range, replace the button assembly.
  4. Test for 2.7 K - 3.3 K Ω between the keypad supply voltage terminal A and the keypad signal terminal B while pressing the blue On-Star® button.
    5. ⇒If not within the specified range, replace the button assembly.
  5. Test for 12.5 K - 13.5 K Ω between the keypad supply voltage terminal A and the keypad signal terminal B while pressing the red emergency button.
    6. ⇒If not within the specified range, replace the button assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  OnStar Button Assembly Replacement
    •  Control Module References for CIM replacement, setup, and programming