P0433 - Heated Catalyst Efficiency Below Threshold Bank 2
- Air leak before catalytic converter
- Faulty oxygen sensor
- Faulty Catalytic Converter
- Engine Light ON (or Service Engine Soon Warning Light)
The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).
A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.