Catalyst Heater Supply Voltage Bank 1

Common symptoms

What you'll notice

• Check the fuse for the catalyst heater supply voltage and replace if blown.
• Inspect and repair any damaged or loose wiring connections related to the catalyst heater supply voltage.
• Test and replace the catalyst heater relay if it is faulty.
• Check and fix any issues with the catalyst heater control module.
• If all other solutions fail, replace the catalyst heater itself.

Common causes

Most likely first

1. Faulty catalytic converter
2. Malfunctioning oxygen sensor
3. Defective or damaged wiring connected to the catalyst heater
4. Faulty relay or fuse related to the catalyst heater
5. Problems with the engine control module (ECM) affecting the catalyst heater

How to diagnose & fix

Work through it in order

1. Check engine light illuminated
2. Decreased fuel efficiency
3. Engine misfires or stutters
4. Poor acceleration or lack of power
5. Higher emissions levels