Catalyst Heater Circuit Low Bank 1

Common symptoms

What you'll notice

• Check and repair any wiring or connection issues related to the catalyst heater circuit in bank 1.
• Inspect and replace the catalyst heater relay if it is faulty.
• Test and replace the catalyst heater temperature sensor if it is malfunctioning.
• Clean or replace the catalytic converter if it is damaged or clogged.

Common causes

Most likely first

1. Faulty catalytic converter
2. Malfunctioning oxygen sensor
3. Issues with the engine control module (ECM)
4. Wiring or connection problems in the catalyst heater circuit
5. Exhaust leak near the catalytic converter

How to diagnose & fix

Work through it in order

1. Check engine light stays on
2. Decreased engine performance or power
3. Increased fuel consumption
4. Failed emissions test
5. Lack of heat from the vehicle's heater