How do I fix and P0430 error code on a Toyota Highlander?

Alton Alexander
By Alton AlexanderUpdated on June 4th, 2022

P0430 is an error code that indicates a problem with the catalytic converter. This error code happens when the catalytic converter is not able to convert the exhaust gases into less harmful substances. There are several reasons why this error code can occur, such as a clogged catalytic converter, a faulty oxygen sensor, or a problem with the engine.

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1. Check the exhaust pipe for leaks

  1. Disconnect the negative battery cable.
  2. Remove the air filter.
  3. Check for any visible leaks.
  4. Check the exhaust pipe for cracks or other defects.
  5. Repair any leaks.
  6. Reattach the air filter and negative battery cable.
  7. Turn on the engine.

2. Check the oxygen sensor

  1. Remove the fuel cap
  2. Check the air pressure in the fuel system
  3. Remove the air filter
  4. Check the oxygen sensor connection
  5. Replace the oxygen sensor if necessary
  6. Reinstall the air filter
  7. Replace the fuel cap

3. Check the catalytic converter

  1. Remove the air filter.
  2. Remove the cover.
  3. Remove the screws that hold the cover and the converter in place.
  4. Remove the converter.
  5. Check the condition of the catalyst. If it is dirty or clogged, replace the converter.

If the answers above didn't work then you should also try:

  1. Check for a clogged fuel filter
  2. Check for a clogged air filter
  3. Check the spark plugs