how to diagnose a P0420 code on my Tesla Model S Original (2012-2020)

Learn how to diagnose and fix P0420 exhaust system issue in Tesla Model S. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety while working on electrical components.
• Allow the vehicle to cool down if it has been recently driven.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, penetrating oil (if needed).
• Locate the upstream and downstream oxygen sensors.
• Use penetrating oil to loosen the sensors if they are difficult to remove.
• Disconnect the wiring harness from both sensors.
• Remove the sensors using the O2 sensor socket and ratchet.
• Install new O2 sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30-35 ft-lbs).
• Reconnect the wiring harness.

3. Inspect and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool, gasket scraper, new exhaust gaskets.
• Remove the exhaust hangers to gain access to the catalytic converter.
• Unbolt the catalytic converter from the exhaust manifold and rear exhaust pipe.
• Inspect the catalytic converter for physical damage or blockage.
• If replacement is necessary, install the new catalytic converter, ensuring proper alignment.
• Use new gaskets when reassembling, and torque bolts to manufacturer specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle's battery.
• Use an OBD-II scanner to clear the P0420 code.
• Start the vehicle and let it reach operating temperature.