Honda CR-V Fifth Generation (2017-2022) check engine light on with code P0420, what to do?

Solution

1. Preparation

• Gather tools and safety equipment.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use the O2 sensor socket to remove the upstream sensor first. Disconnect the wiring harness.
  3. Install the new oxygen sensor and tighten to manufacturer specifications (typically around 30 lb-ft).
  4. Repeat for the downstream oxygen sensor.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Wrench set, jack and jack stands, exhaust pipe cutter (if needed).
• Sub-steps:
  1. Raise the vehicle and secure it on jack stands.
  2. Remove any heat shields or brackets holding the catalytic converter in place.
  3. Disconnect the exhaust pipes from the catalytic converter. Cut the pipes if necessary.
  4. Remove the old catalytic converter.
  5. Install the new catalytic converter, ensuring all gaskets are replaced.
  6. Reconnect the exhaust pipes and tighten all connections.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code and reset the check engine light.