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Home >> Chevrolet >> 2019 >> Express 2500 Base, Van Cargo Extended, 2.8L Eng VIN 1 >> Repair and Diagnosis >> External Pages >> Different car >> Section 8 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> OnStar Button LED Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 GMC Savana 3500, 2018 GMC Savana 2500, 2018 Chevrolet Express 3500, and 2018 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Green Indicator Test

  1. Ignition OFF/vehicle OFF, and all vehicle systems OFF, disconnect the harness connector at the S51 Telematics Button Assembly. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 6 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF/vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/vehicle in Service Mode.
  4. Test for less than 1 V between the control circuit terminal 4 and ground while commanding the Green Indicator OFF with a scan tool.
    • If 1 V or greater 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.
    • Go to next step: If less than 1 V 
  5. Test for greater than 8 V between the control circuit terminal 4 and ground while commanding the Green Indicator ON with a scan tool.
    • If 8 V or less 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K73 Telematics Communication Interface Control Module.
    • Go to next step: If greater than 8 V 
  6. Test or replace the S51 Telematics Button Assembly.

Red Indicator Test

  1. Ignition OFF/vehicle OFF, and all vehicle systems OFF, disconnect the harness connector at the S51 Telematics Button Assembly. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 6 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF/vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/vehicle in Service Mode.
  4. Test for less than 1 V between the control circuit terminal 5 and ground while commanding the Red Indicator OFF with a scan tool.
    • If 1 V or greater 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON/vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.
    • Go to next step: If less than 1 V 
  5. Test for greater than 8 V between the control circuit terminal 5 and ground while commanding the Red Indicator ON with a scan tool.
    • If 8 V or less 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K73 Telematics Communication Interface Control Module.
    • Go to next step: If greater than 8 V 
  6. Test or replace the S51 Telematics Button Assembly.
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