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Circuit/System Testing

  1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the S48E Multifunction Switch-Instrument Panel. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 2 and ground
    • If 10 Ω or greater 
    1. 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. Vehicle ON.
  4. Verify the scan tool BCM Drive Mode Select Switch parameter displays Inactive.
    • If the parameter does not display Inactive 
    1. Vehicle in Service Mode.
    2. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 6 and ground.
      • If less than 4.8 V
      1. Vehicle OFF, disconnect the harness connector at the K20 engine control module.
      2. Test for infinite resistance between the 5 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 5 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 K20 engine control module.
      • If greater than 5.2 V
      1. Vehicle OFF, disconnect the harness connector at the K20 engine control module, vehicle in Service Mode.
      2. Test for less than 1 V between the 5 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 K20 engine control module.
      • Go to next step: If between 4.8 - 5.2 V
  5. Verify the scan tool BCM Drive Mode Select Switch parameter displays Inactive.
    • If the parameter does not display Inactive 
    1. Vehicle in Service Mode. Disconnect the harness connector at the K20 engine control module.
    2. Test for less than 1 V between the signal circuit terminal 66 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 engine control module.
    • Go to next step: If less than 0.2 V 
  6. Install a 3 A fused jumper wire between the signal circuit terminal 66 and the 5 V reference circuit terminal 46.
  7. Verify the scan tool BCM Drive Mode Select Switch parameter displays Active.
    • If the parameter displays Inactive 
    1. Vehicle OFF, disconnect the harness connector at the K20 engine control module.
    2. Test for infinite resistance between the signal circuit terminal 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 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 K20 engine control module.
    • Go to next step: If greater than 4.8 V 
  8. Replace the S48E Multifunction Switch-Instrument Panel.
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