Introduction: DIY $4 Fix: P0420 Check Engine Light Code

By FredTechLighting
About: I love teaching people how to diagnose and to work on their vehicle, also showing them affordable ways to modify their vehicle without breaking the bank.

Have a PO420 code and want to get rid of it? This DIY should help you :)

This DIY trick is not intended to trick the emissions/smog/inspection station when it comes time to check your vehicle, it is meant for off road vehicles or to keep your check engine light off until you can fix the problem.

Step 1: Remove Downstream (bank 2) Oxygen Sensor(s)

Remove the downstream, or bank 2 oxygen sensor(s) from the vehicle

Acquire a package 2 spark plug anti foulers. You can get them here

Grab your sensor and stick it into the first anti fouler, notice that the sensor is too large to thread into the anti fouler.

Step 2: Drill Out for Desired Size

Drill out the anti fouler using the appropriate drill bit fit to be able to fit your oxygen sensor into the anti fouler allowing it to thread in.

Step 3: Thread It All Together

Thread your oxygen sensor into the drilled out anti fouler, then thread on the non drilled out anti fouler. This will take your oxygen sensor out of the exhaust stream allowing it to get a different reading, keeping your check engine light off until your can fix it.

Step 4: Thread Into Exhaust

Thread the entire assembly into your factory downstream (bank 2) oxygen sensor location.

Plug in the connector for the oxygen sensor.

Enjoy no longer having a check engine light!