Check engine light, code P0420

2010 SUBARU IMPREZA
190,000 MILES • 2.5L • 4 CYL • 4WD • AUTOMATIC
Avatar
CHARLIETACOS
  • MEMBER
  • 1 POST
There is an exhaust leak on the car, it is audible driving at 5-10 mph or 65 mph next to a wall.

Check engine light returns P0420. O2 Sensor 1 reads 2.2-2.7V and O2 Sensor 2 fluctuates greatly.

Question: can the exhaust leak causes both O2 sensor to return such results?

Is my O2 sensor faculty? Is my catalytic converter bad?

Thanks.
Jun 16, 2019 at 12:19 PM
Advertisement
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Good afternoon,

The sensor is reading correctly.

When the rear sensor fluctuates, it is indicating the cat is not doing its job.

I would have the exhaust leak repaired first and then check the readings again. If they are the same then It needs a new catalytic converter.

Roy
Jun 16, 2019 at 3:04 PM