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Home >> Chevrolet >> 2020 >> Trax LS, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 1.8L (2H0) >> Diagnostic Information and Procedures >> DTC P0300-P0304 >> Circuit/System Testing

Circuit/System Testing

  1. Verify the following conditions do not exist:
    • Engine - Vacuum leak
    • Exhaust System - Leaking/Missing components/Restricted
    • Fuel - Contaminated/Dirty/Fill Level = Low - Refer to Alcohol/Contaminants-in-Fuel Diagnosis 
    • Fuel Pressure - High/Low - Refer to Fuel System Diagnosis 
    • Positive Crankcase Ventilation System - Leaking/Incorrect connection/Restricted
    • Vacuum Hoses - Kinked/Leaking/Incorrect connection/Restricted
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no conditions exist 
  2. Ignition/Vehicle - Off
  3. Remove the component: K35 Ignition Coil Module
  4. Verify a condition does not exist with the component: Spark Plug Boot - Carbon Tracking/Fluid intrusion/Visible Damage
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no condition exists 
  5. Connect the electrical connector: @ K35 Ignition Coil Module
  6. Install - J-26792 Ignition Spark Tester @ K35 Ignition Coil Module & Ground
  7. Engine - Cranking
    8. NOTE:

    An erratic or weak spark is considered a no spark condition.

  8. Verify there is spark at the tool.
    • Go to next step: If there is spark 
  9. Ignition/Vehicle - Off
  10. Remove the appropriate component: Spark Plug
  11. Verify the component specifications are correct: Spark Plug - Gap / Heat Range /Torque - Refer to Ignition System Specifications 
    • If not correct 

      Repair or replace as necessary

    • Go to next step: If correct 
  12. Verify a condition does not exist with the component: Spark Plug - Carbon Tracking/Fouled/Visible Damage
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no condition exists 
  13. Swap the two components: Spark Plug - The original component that set the DTC & Another known good component from the vehicle
  14. Engine - Running
  15. Verify the scan tool parameter: Cylinder 1 - 4 Current Misfire Counter = Increments - At the original component location the DTC set.
    • If the parameter value does not increment 

      Replace the component: Spark Plug - The original component that set the DTC

    • Go to next step: If the parameter value increments 
  16. Perform the following procedure/test: Fuel Injector Balance - Refer to Fuel Injector Diagnosis 

    Verify the procedure/test passes.

    • If the procedure/test does not pass 

      Replace the component that failed the test: Q17 Fuel Injector

    • Go to next step: If the procedure/test passes 
  17. Verify the condition does not exist: An engine mechanical condition - Refer to Symptoms - Engine Mechanical
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no condition exists 
  18. All OK.
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