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Home >> Cadillac >> 2018 >> Escalade Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 11 (Engine Controls And Fuel - 6.0L (L96) - DTC P0351 To DTC P2636 And Diagnostic Information And Procedures) >> Diagnostic Information And Procedures >> Malfunction Indicator Lamp (MIL) Diagnosis >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Any malfunction indicator lamp requesting DTCs that may be set should be diagnosed first.
  1. Ignition OFF.
  2. Disconnect the X1 harness connector at the K20 Engine Control Module.
  3. Ignition ON, verify the malfunction indicator lamp does not illuminate.
    • If the malfunction indicator lamp illuminates 
    1. Test for infinite resistance between the control circuit terminal X1 68 and ground.
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance, replace the P16 Instrument Cluster.
    • Go to next step: If the malfunction indicator lamp does not illuminate 
  4. Connect a 3 A fused jumper wire between the control circuit terminal X1 68 and ground.
  5. Verify the malfunction indicator lamp illuminates.
    • If the malfunction indicator lamp illuminates 

      Replace the K20 Engine Control Module.

    • If the malfunction indicator lamp does not illuminate 
    1. Test for less than 1 V between the control circuit terminal X1 68 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    2. Ignition OFF.
    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.
  6. Ignition OFF, disconnect the harness connector at the instrument cluster.
  7. Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 19 and ground.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the ignition voltage circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ignition voltage circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
    • Go to next step: If the test lamp illuminates 
  8. Replace the P16 Instrument Cluster.
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