P019B
O2 Sensor Delayed Response Lean to Rich Bank 1 Sensor 3
Generic OBD-II
Common symptoms
What you'll notice
- Check and replace the oxygen sensor (Bank 1 Sensor 3).
- Inspect the wiring and connections associated with the oxygen sensor.
- Clean or replace the Mass Air Flow (MAF) sensor.
- Check for any exhaust leaks and fix them.
Common causes
Most likely first
- Faulty oxygen sensor in Bank 1 Sensor 3
- Damaged or malfunctioning catalytic converter
- Vacuum leak in the intake manifold
- Fuel injector issues, such as clogging or malfunction
- Faulty engine control module (ECM) or oxygen sensor heater circuit malfunction
How to diagnose & fix
Work through it in order
- Poor fuel economy
- Engine misfires or stumbles
- Rough idle or hesitation
- Check Engine Light (CEL) illumination
- Decreased engine performance
Read & clear P019B yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.