Skip to content
Tahoe / Yukon Service Manual

OnStar Button Malfunction

Cellular, Entertainment, and Navigation | Diagnostic Information and Procedures | Document ID: 5184106 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. DTC Descriptors DTC B1346 Keypad Signal For symptom byte information refer to Symptom Byte List Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
2514 Signal B1346 11 B1346 13 — B1346 63
2350 Ground — B1346 13 — —

Circuit/System Description The OnStar® button assembly consists of 3 buttons: Call/Answer, OnStar® Call Center, and OnStar® Emergency. The K73 Telematic Control Module supplies the OnStar® button assembly with 10 V via circuit 2515. Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the K73 Telematic Control Module over the keypad signal circuit 2514. Depending upon the voltage range returned, the K73 Telematic Control Module is able to identify which button has been pressed. Conditions for Running the DTC Vehicle in Service Mode. Battery voltage must be between 9–16 V. Conditions for Setting the DTC B1346 11 Circuit 2514 is short to ground. B1346 13 Circuit 2514 has an open/high resistance. B1346 63 A valid signal on the keypad signal circuit 2514 for longer than 15 s. If one of the OnStar® buttons is held or stuck for 15 s or greater, the K73 Telematic Control Module will set this DTC. Action Taken When the DTC Sets The OnStar® status LED turns red. No calls can be placed. The K73 Telematic Control Module will ignore all inputs from the OnStar® button assembly. Conditions for Clearing the DTC The condition responsible for setting the DTC no longer exists. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. Diagnostic Aids After any repair is made to the 10 V reference circuit or button signal circuit the fuse to the K73  Telematic Control Module must be removed for 30 s to reset the control module. Failure to do so could result in incorrect diagnosis. 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 Testing

  1. Vehicle off, disconnect the X1 connector at the A103 Roof Console. It may take up to 2 min for all vehicle systems to power down.
  2. Test the ground circuit terminal 12 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.
  3. Disconnect the X2 connector at the A103 Roof Console, vehicle in service mode.
  4. Test for 8.0–10.5 V between the control circuit terminal 1 and ground. ⇒ If less than 8.0 V 4.1. Vehicle off, disconnect the X1 harness connector at the K73 Telematic Control Module. 4.2. Test circuit 2515 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 4.3. Test circuit 2515 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. 4.4. Replace the K73 Telematic Control Module. ⇒ If greater than 10.5 V 4.1. Test circuit 2515 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 4.2. Replace the K73 Telematic Control Module. ⇓ If between 8.0–10.5 V
  5. Vehicle off, Test for 500–900 Ω between the signal circuit terminal 2 and ground. ⇒ If less than 500 Ω 5.1. Disconnect the X1 harness connector at the K73 Telematic Control Module. 5.2. Test circuit 2514 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 5.3. Replace the K73 Telematic Control Module. ⇒ If greater than 900 Ω 5.1. Disconnect the X1 harness connector at the K73 Telematic Control Module, vehicle in service mode. 5.2. Test circuit 2514 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 5.3. Vehicle off, test circuit 2514 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. 5.4. Replace the K73 Telematic Control Module. ⇓ If between 500–900 Ω
  6. Replace the A103 Roof Console. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Roof Console Replacement For control module replacement, programming, and setup refer to: Control Module References