how to diagnose a P0301 code in my Toyota RAV4 Fourth Generation (2013-2018)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Disconnect the negative battery terminal to avoid electrical shock.
  2. Remove the ignition coil from cylinder 1 (use a socket set).
  3. Remove the spark plug using a spark plug socket and ratchet.
  4. Inspect the spark plug for wear or fouling; replace if necessary (recommended gap: 0.044 inches).
  5. Install the new spark plug and torque to manufacturer specifications (typically 13 ft-lbs).
  6. Reinstall the ignition coil and reconnect the battery.

3. Check and Replace Ignition Coil

• Sub-steps:
  1. If the spark plug is in good condition, proceed to check the ignition coil.
  2. Disconnect the ignition coil connector and remove the coil.
  3. Test the ignition coil with a multimeter (check for primary and secondary resistance).
  4. If out of specifications, replace the ignition coil with a new one.
  5. Reinstall the ignition coil and reconnect the connector.

4. Test Fuel Injector

• Sub-steps:
  1. If the issue persists, check the fuel injector for cylinder 1.
  2. Disconnect the fuel injector connector and use a noid light to test for pulse.
  3. If no pulse is detected, check wiring and ECM.
  4. If the injector is faulty, remove and replace it.
  5. Reconnect the fuel injector connector.

5. Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert a compression gauge into the cylinder.
  3. Crank the engine and observe the compression reading (should be within manufacturer specs).
  4. If compression is low, further diagnosis is needed for potential internal engine issues.