what does it mean if my Tesla Outback has a P0421 code?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle battery to ensure safety during repairs.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter
• Remove the upstream O2 sensor from the exhaust manifold.
  • Sub-step: Use the O2 sensor socket and carefully unscrew the sensor.
• Test the sensor with a multimeter for proper voltage output.
  • Sub-step: If the sensor is out of range, replace it with a new one.
• Install the new O2 sensor and torque it to the manufacturer's specifications.

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

• Tools Required: Socket set, exhaust gasket, torque wrench
• Remove the exhaust pipe connected to the catalytic converter.
  • Sub-step: Use a socket set to unbolt the connections, and be careful of any exhaust hangers.
• Inspect the catalytic converter for damage or clogging.
• If damaged, replace the catalytic converter with a new unit.
  • Sub-step: Install using new gaskets and torque to manufacturer specifications.

4. Reconnect and Reset the System

• Reconnect the vehicle battery.
• Clear the P0421 code using the OBD-II scanner.
• Start the engine and let it idle for a few minutes.