why does my Toyota Corolla E170 (2013-2019) have a check engine light with P0301 code

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to avoid electrical shocks.

2. Inspect and Replace Spark Plug

• Sub-steps:
  • Remove the engine cover if applicable.
  • Use a socket and extension to remove the spark plug from cylinder 1.
  • Inspect the spark plug for wear, carbon buildup, or damage.
  • If necessary, replace the spark plug with the manufacturer's specified part.
  • Torque the new spark plug to the recommended specification (typically around 13-16 lb-ft).

3. Check and Replace Ignition Coil

• Sub-steps:
  • Remove the ignition coil from cylinder 1 by unscrewing the bolts.
  • Inspect the ignition coil for cracks or signs of wear.
  • If faulty, replace it with a new ignition coil compatible with the Toyota Corolla E170.
  • Reinstall the ignition coil and torque bolts to the manufacturer’s specification.

4. Inspect Fuel Injector

• Sub-steps:
  • Disconnect the fuel injector connector.
  • Remove the fuel rail if necessary, and inspect the fuel injector for cylinder 1.
  • Clean the injector or replace it if it is clogged or damaged.
  • Reassemble the fuel rail and reconnect the fuel injector.

5. Perform Compression Test

• Sub-steps:
  • Remove the spark plug from cylinder 1.
  • Insert a compression gauge into the spark plug hole.
  • Crank the engine and record the compression reading.
  • If compression is low, further investigation is needed (e.g., checking piston rings, valves).