• | 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. |
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 |
Inside Rearview Mirror Ground | -- | 1 | -- | -- |
1. OnStar® LED Inoperative 2. LED Illuminated At All Times 3. OnStar® Buttons Inoperative |
The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center and OnStar® Emergency. Ten volts is supplied to the button assembly on 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 vehicle communication interface module (VCIM) on the keypad signal circuit. Depending upon the voltage range returned, the VCIM is able to identify which button has been pressed.
• | Ignition ON. |
• | Battery voltage must be between 9-16 volts. |
The VCIM detects a short to voltage, short to ground, or an open/high resistance on the keypad supply voltage circuit.
• | The OnStar® status LED turns red. |
• | No calls can be placed. |
• | The VCIM will ignore all inputs from the OnStar® button assembly. |
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC clears after 50 malfunction-free ignition cycles. |
Entertainment/Communication Connector End Views
OnStar Description and Operation
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If less than the specified range, test the keypad signal circuit for a short to ground. |
⇒ | If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the VCIM. |
⇒ | 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 VCIM. |
⇒ | If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the VCIM. |
⇒ | If less than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the VCIM. |
⇒ | If less than the specified range, replace the inside rearview mirror. |
⇒ | If not within the specified range, replace the inside rearview mirror. |
⇒ | If not within the specified range, replace the inside rearview mirror. |
⇒ | If not within the specified range, replace the inside rearview mirror. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for VCIM replacement, setup, and programming |