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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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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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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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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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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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 Telematics 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 Telematics Button Assembly 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 5 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 S51 Telematics Button Assembly signal circuit terminal 3 and ground.
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5.
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If the value is greater than the specified range, check if there is a short-circuit to voltage in the S51 signal circuit of the Telematics keypad. If the circuit test result is normal, replace the K73 telematics communication interface control module.
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6.
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Ignition OFF, test for 450-850 kΩ between the S51 Telematics Button Assembly signal circuit terminal 3 and ground.
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7.
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If the value is less than the specified range, check if there is a short-circuit to ground in the S51 signal circuit of the Telematics keypad. If the circuit test result is normal, replace the K73 telematics communication interface control module.
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8.
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If the value is greater than the specified range, check if there is an open circuit/high resistance in the S51 signal circuit of the Telematics keypad. If the circuit test result is 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 S51 Telematics Button Assembly 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.
