Introduction
The P0302 diagnostic trouble code indicates that the powertrain control module (PCM) has detected a specific misfire in Cylinder 2. Similar to P0301, this code pinpoints ignition, fuel delivery, or mechanical compression failure isolated to the second cylinder, causing irregular engine rotation and emissions spikes.
Common Symptoms
- Check Engine Light blinking or illuminated.
- Engine shuddering, shaking, or rough idling.
- Sluggish acceleration and loss of engine power.
- Exhaust emitting unburned fuel smells.
Primary Causes
- Failing Spark Plug: Worn, fouled, or improperly gapped spark plug in Cylinder 2.
- Faulty Ignition Coil: Weak or dead coil pack supplying Cylinder 2.
- Clogged or Faulty Fuel Injector: Defective injector failing to atomize fuel correctly in Cylinder 2.
- Low Mechanical Compression: Leaking valves or worn piston rings in Cylinder 2.
Step-by-Step Diagnosis & Fixes
- Swap Ignition Parts: Switch the Cylinder 2 spark plug or coil with another cylinder to see if the misfire code shifts.
- Inspect Spark Plug: Remove the Cylinder 2 spark plug to check for oil fouling, carbon buildup, or a damaged electrode gap.
- Test Injector Pulse: Use a diagnostic light or stethoscope to verify that the Cylinder 2 fuel injector is receiving proper electrical triggers.
- Compression Test: Conduct a cylinder compression test if ignition and fuel components prove to be functioning normally.