how to fix P0303 code in Toyota Corolla E170 (2013-2019)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Toyota Corolla E170 (2013-2019). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Spark Plug Replacement

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil cover (if applicable).
• Disconnect the electrical connector from the ignition coil on cylinder 3.
• Remove the ignition coil using a socket.
• Remove the spark plug using a spark plug socket.
• Install a new spark plug with a gap of 0.044 inches (1.1 mm) and torque to 13 lb-ft (18 Nm).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Ignition Coil Testing/Replacement

• If the ignition coil was found faulty during diagnostics, replace it:
  • Remove the defective ignition coil as described above.
  • Install a new ignition coil and torque to the manufacturer specifications (usually around 10 lb-ft or 14 Nm).
  • Reinstall the ignition coil cover.

4. Fuel Injector Testing/Replacement

• If the injector was found faulty:
  • Disconnect the fuel pump relay and start the engine until it stalls to relieve fuel pressure.
  • Remove the fuel injector wiring harness.
  • Unbolt and remove the fuel rail to access the injector.
  • Replace the faulty fuel injector, ensuring to lubricate the O-ring with clean engine oil before installation.
  • Reassemble the fuel rail and reconnect the wiring harness.

5. Reassemble and Clear Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0303 code.
• Start the engine and observe for any check engine light re-illuminating.