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Home >> Chevrolet >> 2017 >> Spark LT, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 81 (Engine Controls And Fuel - 1.6L (LWC) - DTC P0243 To DTC P2635 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Electronic Ignition System Diagnosis >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:

Do not perform this diagnostic procedure unless you were sent here from a misfire DTC or the Engine Cranks But Does Not Run diagnostic.

  1. Ignition/Vehicle Off and all vehicle systems OFF, disconnect the harness connector at the appropriate T8 Ignition Coil. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 5 Ω between the ground circuit terminal 1 and ground.
    • If 5 Ω or greater 
    1. Ignition/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 5 Ω 
  3. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.
    • If 5 Ω or greater 
    1. Ignition/Vehicle Off, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the low 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.
    • Go to next step: If less than 5 Ω 
  4. Ignition On/Vehicle in Service Mode.
  5. Verify a test lamp illuminates between the ignition circuit terminal 4 and ground.
    • If the test lamp does not illuminate 
    1. Ignition/Vehicle Off.
    2. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • Go to next step: If the test lamp illuminates 
  6. Ignition/Vehicle Off, exchange the suspect T8 Ignition Coil with the T8 Ignition Coil of a known functioning cylinder.
  7. Engine Running.
  8. Verify the scan tool Cylinder 1 - 4 Current Misfire Counter does not increment for the same cylinder that the suspect T8 Ignition Coil was removed from.
    • If increments 

      Replace the K20 Engine Control Module.

    • Go to next step: If does not increment 
  9. Test or replace the T8 Ignition Coil.
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