P0433: Heated Catalyst Efficiency Below Threshold (Bank 2)
The P0433 code indicates that the heated catalytic converter on Bank 2 (the side of the engine opposite cylinder #1) is not operating as efficiently as expected. The powertrain control module (PCM) monitors the oxygen sensors before and after the catalyst to measure its ability to store oxygen. When the post-catalyst sensor readings are too similar to the pre-catalyst sensor, it suggests the catalyst is not effectively reducing emissions. This can be caused by a faulty catalytic converter, exhaust leaks, or issues with the oxygen sensors themselves.
01. Most Common Causes
- Faulty heated catalytic converter (Bank 2)
- Exhaust leak before or after the converter
- Faulty oxygen sensor (Bank 2, Sensor 2)
- Engine misfire causing unburned fuel to damage the catalyst
- Oil or coolant contamination in the exhaust
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Decreased fuel economy
- Rotten egg smell from exhaust (sulfur odor)
- Possible hesitation or loss of power
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data to confirm P0433 and check for related codes.
Step 2: Inspect exhaust system for leaks, damage, or loose connections, especially near Bank 2.
Step 3: Monitor oxygen sensor data with a scan tool; compare Bank 2 Sensor 1 and Sensor 2 readings. A properly functioning converter will show a steady post-catalyst signal.
Step 4: Perform a catalytic converter efficiency test by revving the engine and observing oxygen sensor response.
Step 5: If all else checks out, replace the Bank 2 catalytic converter.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but it may cause further damage to the catalytic converter and oxygen sensors, and you will likely fail an emissions test. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Replacing a catalytic converter can range from $500 to $2,500 depending on the vehicle and parts. Oxygen sensor replacement is usually $150-$300.