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Tahoe / Yukon Service Manual

OnStar Button LED Malfunction

Cellular, Entertainment, and Navigation | Diagnostic Information and Procedures | Document ID: 6159667 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. Circuit Description The OnStar® status Indicators are located in the button assembly. The Green Indicator is illuminated when there is a current subscription and the system is ON and operating normally. When the Green Indicator is green and flashing, it is an indication that a call is in progress. When the Red Indicator is illuminated, a system malfunction is present. In the event there is a system malfunction and the OnStar® system is still able to make a call, the Indicator will flash red during the call. The OnStar® Indicators are controlled by the K73 Telematic Control Module via the keypad Green Indicator control circuit and the keypad Red Indicator control circuit. Reference Information Schematic Reference OnStar/Telematics Schematics Connector End View Reference Master Electrical Component List Description and Operation OnStar 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

  1. Verify either the Green or Red Indicator is ON with the ignition ON. ⇒ If the Green or Red Indicator is not ON. 1.1. Contact the OnStar Center to confirm the vehicle has a current subscription. ⇒ If there is a current subscription refer to Circuit/System Testing. ⇒ If there is not a current subscription, advise the customer to contact the OnStar Call Center. ⇒ If the Red Indicator is ON.
  2. Verify no DTCs are set. ⇒If any DTCs are set ⇒ If any DTCs are set Refer to Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If the Green Indicator is ON.
  3. A fault is not currently present and may be an intermittent condition. . Circuit/System Testing
  4. Ignition OFF, disconnect the connector at the A103 Roof Console. It may take up to 2 min for all vehicle systems to power down.
  5. Test ground circuit terminal 20 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found.
  6. Disconnect the connector at the A103 Roof Console. Ignition ON
  7. Test the following control circuits for greater than 8.5 V Terminal 17 and ground Terminal 18 and ground. ⇒ If less than 8.5 V on both circuits 4.1. Ignition OFF, test the following circuits for a short to ground. Circuit 2516 Circuit 2517 ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 4.2. Test the following circuits for an open/high resistance. Circuit 2516 Circuit 2517 ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 4.3. Replace the K73 Telematic Control Module. ⇓ If greater than 8.5 V on either circuit.
  8. Replace the A103 Roof Console. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Refer to: Control Module References for control module replacement, programming and setup. Roof Console Replacement