What are the common causes of P0433?

A failed heated catalyst on bank 2. A lazy oxygen sensor on bank 2. A weak bank 2 catalyst heater circuit. An exhaust leak ahead of the heated catalyst. A misfire or rich condition loading the converter.

Check the heated catalyst temperature rise after a cold start. Compare upstream and downstream O2 sensor signals on bank 2. Test the catalyst heater circuit and relay. Check for exhaust leaks ahead of the converter. Replace the heated bank 2 catalyst if efficiency stays low. Clear the code and retest.

P0433

Heated Catalyst Efficiency Below Threshold Bank 2

System: Auxiliary emission controls (P code)
Lamp: Check Engine Light
Category: Powertrain - Auxiliary Emissions Controls

What it means

P0433 means Heated Catalyst Efficiency Below Threshold Bank 2.

Check these first

A failed heated catalyst on bank 2
A lazy oxygen sensor on bank 2
A weak bank 2 catalyst heater circuit
An exhaust leak ahead of the heated catalyst
A misfire or rich condition loading the converter

What to do next

Check the heated catalyst temperature rise after a cold start
Compare upstream and downstream O2 sensor signals on bank 2
Test the catalyst heater circuit and relay
Check for exhaust leaks ahead of the converter
Replace the heated bank 2 catalyst if efficiency stays low
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.