how to address P0303 code on Toyota Corolla E170 (2013-2019)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Toyota Corolla E170. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, Torque wrench, Spark plug socket, Ratchet, Screwdrivers
• Remove the ignition coil from cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Unbolt the ignition coil using the socket set.
  3. Remove the ignition coil and inspect it for cracks or wear.
• Check the spark plug in cylinder 3:
  1. Remove the spark plug using a spark plug socket.
  2. Inspect the spark plug for wear, carbon buildup, or damage.
  3. Replace the spark plug if necessary, ensuring to torque to manufacturer specifications (typically around 13-16 lb-ft).
• Reinstall the ignition coil or replace it if faulty:
  1. Position the ignition coil back onto the spark plug.
  2. Tighten the bolts to manufacturer specifications (usually around 80-100 in-lbs).
  3. Reconnect the electrical connector.

3. Check and Clean Fuel Injector

• Tools Required: Fuel injector cleaner, Socket set
• Remove the fuel injector for cylinder 3:
  1. Depressurize the fuel system by removing the fuel pump fuse and running the engine until it stalls.
  2. Remove the intake manifold or necessary components to access the fuel rail.
  3. Disconnect the fuel line and electrical connector from the injector.
  4. Unbolt and remove the injector.
• Clean or replace the fuel injector:
  1. Use a fuel injector cleaning kit to clean the injector.
  2. If cleaning does not improve performance, replace with a new injector.
• Reinstall the fuel injector:
  1. Ensure O-rings are lubricated and seated properly.
  2. Reconnect the fuel line and electrical connector.

4. Compression Test (If Needed)

• Tools Required: Compression tester
• Test the compression of cylinder 3:
  1. Remove the spark plug from cylinder 3.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for a few seconds and read the compression value.
• If compression is below 130 psi, consider further diagnostics into the engine internals.