how to troubleshoot the P0301 code in my Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1 (usually involves unbolting and disconnecting the electrical connector).
• Take out the spark plug from cylinder 1 using a spark plug socket.
• Inspect the spark plug for wear or carbon buildup; if worn, replace it with a new one (use OEM specification plugs).
• Reinstall the spark plug and torque it to the manufacturer's specifications (typically 13-16 lb-ft).

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil using a multimeter to check the resistance (refer to specifications for your model).
• If faulty, replace the ignition coil with a new one (ensure it's compatible with your engine).
• Reinstall the ignition coil and reconnect the electrical connector.

4. Test Fuel Injector

• Using a noid light, connect it to the fuel injector connector to check for proper signal.
• If the noid light does not illuminate, check the wiring for shorts or breaks.
• If the injector signal is proper, remove the fuel injector from cylinder 1 and inspect it for clogs. Clean or replace if necessary.

5. Perform Compression Test

• Remove the spark plug from cylinder 1 and install a compression tester.
• Crank the engine and read the compression value. It should be within the manufacturer's specified range.
• If compression is low, investigate potential causes such as valve issues, piston rings, or head gasket failure.