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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 207 (Engine Control System - Self-Diagnostics) >> Diagnostic Tests >> DTC P0301, P0302, P0303, P0304: Cylinder Specific Misfire Detected >> Test Description

Test Description

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 1  - The Diagnostic System Check - Engine Controls prompts the technician to complete some basic checks and store freeze frame data, if applicable. This creates an electronic copy of data taken when fault occurred. Information is then stored in the scan tool for later reference.
  2. 2  - This step verifies whether misfire is present. The scan tool will display increasing counts in MISFIRE CURRENT CYL. NO. data parameter of misfiring cylinder when a misfire is occurring.
  3. 3  - This step checks whether MIL is the result of a hard failure or an intermittent condition. Operating vehicle in CHECK MODE enhances the diagnostic capabilities of the PCM. Scan tool will display increasing counts in MISFIRE CURRENT CYL. NO. data parameter of the cylinder that is experiencing a misfire.
  4. 4  - Fault not present indicates the condition that caused DTC P0301-P0304 to set is intermittent and not currently present. If no other DTCs are stored, see DIAGNOSTIC AIDS  for additional information on diagnosing an intermittent DTC P0301-P0304.
  5. 5  - This step is to verify if the misfire is caused by a fault in the ignition system.
  6. 13  - Contaminants in fuel, such as alcohol or water, can create a misfire condition.
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