how to fix P0300 code in Toyota Corolla E170 (2013-2019)?

Solution

1. Preparation

• Gather tools and parts necessary for the repair.
• Safety gear: gloves and safety glasses.
• Disconnect the negative battery terminal to prevent electrical shocks.

2. Inspect and Replace Ignition Components

1. Spark Plug Inspection

   • Remove the spark plugs using a socket wrench.
   • Inspect for wear, carbon buildup, or damage.
   • Replace spark plugs if they are worn or the gap is out of specification (0.043 inches for Toyota Corolla).

2. Ignition Coil Inspection

   • Remove the ignition coils from each cylinder.
   • Check for cracks or signs of arcing.
   • Replace any faulty ignition coils.

3. Ignition Wire Inspection

   • Inspect the ignition wires for fraying or corrosion.
   • Replace any damaged wires with OEM parts.

3. Fuel System Check

1. Fuel Pressure Test
   • Connect a fuel pressure gauge to the fuel rail.
   • Turn the ignition to the "On" position without starting the engine to check the pressure (should be between 43-50 psi).
   • If pressure is low, check the fuel filter and fuel pump for issues.

4. Air Intake and Vacuum System Inspection

1. Inspect for Vacuum Leaks
   • Visually inspect all vacuum hoses and intake manifold for cracks or disconnections.
   • Use a smoke machine or carburetor cleaner to locate leaks.
   • Replace any damaged hoses or seals.

5. Engine Mechanical Condition Check

1. Compression Test
   • Remove all spark plugs.
   • Insert a compression gauge into each cylinder and crank the engine.
   • Compare readings; a healthy engine should have similar compression across all cylinders (around 180 psi).
   • Address any discrepancies by inspecting valves and piston rings.