how to fix P0301 code on Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, and vacuum gauge.
• Disconnect the negative battery terminal to ensure safety during the repair.

2. Inspect Ignition Components

• Remove the Engine Cover: Use a socket set to unbolt and remove the plastic engine cover.
• Remove the Ignition Coil:
  • Disconnect the electrical connector from the ignition coil.
  • Unbolt the ignition coil using a socket, then gently pull it out.
• Inspect Spark Plug:
  • Unscrew the spark plug using a spark plug socket.
  • Check for wear, carbon buildup, or damage to the electrode.
  • Replace the spark plug if worn or damaged.

3. Test Fuel Injector

• Remove the Fuel Injector Connector: Disconnect the electrical connector from the fuel injector at cylinder 1.
• Test the Injector: Use a multimeter to check for proper resistance (usually between 12-16 ohms).
• Replace if Necessary: If the injector does not meet specifications, replace it with a new one.

4. Check for Vacuum Leaks

• Inspect Vacuum Hoses: Look for cracked or disconnected hoses around the intake manifold and throttle body.
• Use a Vacuum Gauge: Connect a vacuum gauge to the intake manifold to check for proper readings (typically 17-21 inHg at idle).

5. Perform Compression Test

• Remove Spark Plug: Ensure the spark plug for cylinder 1 is removed.
• Insert Compression Tester: Screw in the compression tester into the spark plug hole.
• Crank Engine: Crank the engine several times to get a reading. A reading below 120 psi indicates potential issues with the cylinder.

6. Reassemble and Test

• Reinstall the ignition coil, spark plug, and engine cover in reverse order.
• Reconnect the negative battery terminal.