Code P0420?

SIDDHANT286

MEMBER
2010 TOYOTA RAV4
2.5L
4 CYL
4WD
AUTOMATIC
154,000 MILES

I am getting P0420 on my vehicle listed above base model with 154,000 km (95,691 miles). Replaced spark plugs and O2 censor. Used fuel injector cleaners and catalytic converter cleaners. The code comes up every 30km after removing the code. The worst part is when the code comes up, it disables the cruise control and the 4WD lock. So, I have to remove the code from the OBD scanner for them to work. Exhaust sometimes sounds loud when starting in the morning.

Friday, November 3rd, 2023 AT 9:15 AM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
50,363 POSTS

The most common cause for a P0420 code is a faulty catalytic converter, which would explain the loud exhaust in the morning as well. Here is how to replace it in the images below, to make sure this is the problem you can install a spark plug extender into the o2 sensor behind the cat, if the light stays out you know the cat is bad. Here is how to change it out. Check out the images (below). Please let us know if you need anything else to get the problem fixed.

Images (Click to make bigger)