OnStar Button Malfunction
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OnStar Button Malfunction
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Keypad Supply Voltage
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B2476 00
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B2476 00
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B2476 00
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-
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Keypad Green LED Control
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1
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1
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2
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-
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Keypad Red LED Control
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1
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1
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2
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-
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Keypad Signal
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3
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3
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-
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B2482 00
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Inside Rearview Mirror Ground
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-
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1
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-
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-
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1. OnStar® LED Inoperative
2. LED Illuminated At All Times
3. OnStar® Buttons Inoperative
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Circuit/System Description
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The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center, and OnStar® Emergency. The telematics communication interface control module supplies the OnStar® button assembly with 10 V 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 telematics communication interface control module over the keypad signal circuit. Depending upon the voltage range returned, the telematics communication interface control module is able to identify which button has been activated.
Schematic Reference
OnStar Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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Note
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Contact the OnStar® Call Center first before pressing the emergency button in order to notify them of the test.
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Ignition ON, press the OnStar® Call buttons one at the time. Verify that all of the OnStar® buttons operate normally.
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1.
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Ignition OFF, disconnect the harness connector at the inside rearview mirror.
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2.
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Test for less than 10 Ω between the mirror ground circuit terminal 5 and ground.
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3.
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If greater than the specified range, test the ground circuit for an open/high resistance.
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4.
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Ignition ON, test for less than 1 V between the keypad signal circuit terminal 3 and ground.
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5.
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If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
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6.
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Ignition OFF, test for 500k-800k Ω between the keypad signal circuit terminal 3 and ground.
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7.
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If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit tests normal, replace the K73 telematics communication interface control module.
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8.
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If greater than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
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9.
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Ignition ON, test for 9.5-10.5 V between the keypad supply voltage circuit terminal 4 and ground.
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10.
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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 K73 telematics communication interface control module.
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11.
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If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
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12.
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If all circuits test normal, test or replace the button assembly.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
