how to troubleshoot my Toyota Camry XV40 (2007-2011) with P0301 code?

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, torque wrench, compression tester, multimeter.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect Ignition Components

• Ignition Coil:
  • Remove the engine cover if necessary.
  • Disconnect the electrical connector from the ignition coil on cylinder 1.
  • Remove the ignition coil using a socket set.
  • Inspect the coil for cracks or corrosion; replace if damaged.
• Spark Plug:
  • Remove the spark plug using a spark plug socket.
  • Inspect the spark plug for wear and carbon deposits; replace if necessary.
  • Ensure the spark plug gap is set to manufacturer specifications (usually around 0.043 inches for Toyota).

3. Check Fuel Injector

• Fuel Injector:
  • Disconnect the electrical connector from the fuel injector on cylinder 1.
  • Use a multimeter to check for proper voltage at the connector while cranking the engine; replace if there is no voltage.
  • If voltage is present, perform a fuel injector balance test to ensure it is delivering fuel properly.

4. Compression Test

• Compression Test:
  • Remove the spark plug from cylinder 1 and install the compression tester.
  • Crank the engine a few revolutions and record the compression reading; compare to manufacturer specifications (should be around 180 psi).
  • If compression is low, further inspection for valve or head gasket issues is required.

5. Reassemble and Reconnect

• Reinstall any components that were removed, ensuring all bolts are torqued to specification.
• Reconnect the negative battery terminal.

Note: If all components check out and the problem persists, further investigation may be required into the engine control module or wiring harness.