2021 GMC Terrain SLFACTORY OEM SERVICE PROCEDURE

Circuit/System Testing

NOTE:
  • 10 V reference circuit measurement may vary with vehicle battery voltage.
  • Test for voltage range with vehicle battery measuring at a minimum of 11.5 V
  1. Vehicle OFF/Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A98 Front Overhead Console 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 5 and ground.
    • If 10 Ω or greater 
    1. Vehicle OFF/Ignition 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. Vehicle in Service Mode/Ignition ON.
  4. Test for 8.0 - 10.5 V between the 10 V reference circuit terminal 16 and ground.
    • If less than 8.0 V 
    1. Vehicle OFF/Ignition OFF, disconnect the harness connector at the K73 Telematics Communication Interface Control Module.
    2. Test for infinite resistance between the 10 V reference 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 10 V reference 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.
    • If greater than 10.5 V 
    1. Vehicle OFF/Ignition OFF, disconnect the harness connector at the K73 Telematics Communication Interface Control Module, vehicle in Service Mode/Ignition ON.
    2. Test for less than 1 V between the 10 V reference 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 between 8.0 - 10.5 V 
  5. Vehicle OFF/Ignition OFF.
  6. Test for 500 - 900 Ω between the signal circuit terminal 17 and ground.
    • If less than 500 Ω 
    1. Disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K73 Telematics Communication Interface Control Module.
    • If greater than 900 Ω 
    1. Disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, vehicle in Service Mode/Ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Vehicle OFF.
    4. Test for less than 2 Ω in the signal 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 between 500 - 900 Ω 
  7. Test or replace the A98 Front Overhead Console Assembly.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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