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Home >> GMC >> 2018 >> Terrain SL >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Entertainment Systems >> Cellular System, Entertainment System, And Navigation System - Diagnostic Information And Procedures >> Diagnostic Information And Procedures >> DTC B123E: Radio Keypad Button Signal Circuit >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF/vehicle OFF and all vehicle systems OFF. Disconnect the harness connector at the A22 radio controls. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the following circuits and ground.
    • Ground return terminal 2
    • Low reference terminal 8
    • If 10 Ω of greater 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the P17 Info Display Module.
    2. Test for less than 2 Ω in the circuits end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the P17 Info Display Module
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/vehicle in Service Mode.
  4. Test for 2.5 - 3.5 V on the signal circuit terminal 3 @ the A 22 Radio Controls and ground.
    • If less than 2.5 V 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground.
      • If infinite resistance
    3. 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 A11 Radio.
    • If greater than 3.5 V 
    1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio.
    2. Ignition ON/vehicle in Service Mode, 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.
      • If less than 1 V, replace the A11 radio.
    • Go to next step: If between 2.5 - 3.5 V 
  5. Test or replace the A22 Radio Controls