how to fix P0303 code in my Toyota Corolla E210 (2019-2024)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Toyota Corolla E210. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, noid light, basic hand tools.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

1. Remove the engine cover if applicable.
2. Locate the ignition coil for cylinder 3.
3. Detach the electrical connector from the ignition coil.
4. Unbolt and remove the ignition coil.
5. Use a socket wrench to remove the spark plug from cylinder 3.
   • Torque Specification for Spark Plug: 13 lb-ft (17.5 Nm)
6. Inspect the spark plug for wear or fouling; replace if necessary.
7. Install a new spark plug into cylinder 3 and torque to specification.

3. Test and Replace Ignition Coil (if needed)

1. Using a multimeter, test the resistance of the ignition coil for cylinder 3.
   • Primary Resistance: 0.4 to 2.0 ohms
   • Secondary Resistance: 6,000 to 15,000 ohms
2. If the coil fails the test, install a new ignition coil.
3. Reattach the ignition coil and connector securely.

4. Inspect and Test Fuel Injector

1. Disconnect the fuel injector connector for cylinder 3.
2. Use a noid light to check for pulse at the injector while cranking the engine.
3. If no pulse is detected, check wiring and connectors. Replace the fuel injector if necessary.
4. Reconnect the fuel injector connector.

5. Perform Compression Test (if needed)

1. Remove the spark plug from cylinder 3.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine several times to get a reading.
   • Compression Specification: Approximately 180-200 psi.
4. If compression is low, further investigation into engine condition may be required.