Catalyst Heater Circuit Performance Bank 1

Common symptoms

What you'll notice

• Check the oxygen sensor and replace if necessary
• Inspect and repair any wiring or connections related to the catalyst heater circuit
• Clean or replace the catalytic converter
• Check and repair any exhaust leaks
• Test and replace the powertrain control module (PCM) if all other solutions are unsuccessful

Common causes

Most likely first

1. Faulty catalytic converter
2. Oxygen sensor malfunction
3. Leak in the exhaust system
4. Engine misfire

How to diagnose & fix

Work through it in order

1. Check engine light illuminates on the dashboard
2. Decreased fuel efficiency
3. Loss of power or reduced engine performance
4. Vehicle stalls or struggles to start
5. Strong smell of sulfur or rotten eggs coming from the exhaust