P0432 Catalytic converter: efficiency too low (main catalyst, bank 2)

By: Diagno editorial team · Updated: 2026-10-15

P0432 means: Catalytic converter: efficiency too low (main catalyst, bank 2). The catalytic converter cleans the exhaust gas. OK to drive, but have it checked soon. The repair usually costs about €100–1500 in Estonia. The most common cause: old or damaged catalytic converter. Other possible causes: faulty rear oxygen sensor, exhaust leak.

What it means

The catalytic converter cleans the exhaust gas. The computer compares the oxygen sensors before and after it and found that it no longer cleans well enough. Bank 2 is the side of a V engine without cylinder 1.

What you may notice

• Engine light on
• Emissions fail the inspection
• Sometimes a rotten-egg smell
• Less power if it's blocked

What could be wrong

1. 1Old or damaged catalytic converter
2. 2Faulty rear oxygen sensor
3. 3Exhaust leak
4. 4Misfires or oil burning have ruined the converter

Repair difficulty: Moderate

What you can check yourself

Before replacing an expensive converter, have the oxygen sensors and exhaust leaks checked. That often saves hundreds of euros. Best left to a workshop. It needs a diagnostic tool and experience.

How we fix it

1. We compare both oxygen sensor readings
2. We check for exhaust leaks
3. We fix the cause of misfires or oil burning
4. We replace the converter only when everything else checks out

Standard SAE description: Main Catalyst Efficiency Below Threshold (Bank 2)