LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls And Fuel - 2.5L (LCV) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0300-P0304 >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
  1. Engine - Running
  2. Verify there is no abnormal noise from the component: Engine
    • Go to next step: If no abnormal noise is present 
  3. Perform the scan tool learn/reset function: Crankshaft Position Variation Learn
  4. Verify there are no DTCs set related to the following component/system:
    • B23 Camshaft Position Sensor
    • B26 Crankshaft Position Sensor
    • B52 Heated Oxygen Sensor
    • Q17 Fuel Injector
    • T8 Ignition Coil
    • Fuel System
    • Ignition System
    • Mechanical Condition
    • Go to next step: If no other DTCs are set 
  5. Verify the scan tool parameter: Cylinder 1 - 4 Current Misfire Counter = Does not Increment
    • If the parameter value increments 

      Refer to: Circuit/System Testing

    • Go to next step: If the parameter value does not increment 
  6. Perform the scan tool control function: Cylinder Power Balance - Enable

    Verify the sound of the engine changes the same way when turning off each individual injector.

    • If the engine sound does not change the same way for one or more cylinders 

      Refer to: Circuit/System Testing

    • Go to next step: If the engine sound changes the same way for all cylinders 
  7. Verify the scan tool parameter: Cylinder 1 - 4 Current Misfire Counter = Does not Increment

    Perform the action while monitoring the parameter:

    • Wiggle the harness and connector: K20 Engine Control Module
    • Wiggle the harness and connector: Q17 Fuel Injector
    • Wiggle the harness and connector: T8 Ignition Coil
    • Wiggle the component: Vacuum Hoses
    • If not the specified state 

      Repair or replace as necessary

    • Go to next step: If the specified state 
  8. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

    • If the DTC sets 

      Refer to: Circuit/System Testing

    • Go to next step: If the DTC does not set 
  9. All OK.
scientia non olet · About LEMON Manuals