P0420 code related to cold air intake

A couple of weeks ago I decided to install a cold air intake on my 2001 prerunner and today the dreaded P0420 code popped up.

I'm thinking it's related to the MAF sensor and the intake, so I plan to take that off and reinstall the stock airbox as the truck was running great with no issues before the air take install.

My truck does have 185k miles on it so I'm really hoping it's just the MAF and related cold air intake and not the catalytic converters.

 

They are a complete waste of money

 

Installing the CAI itself did not cause the code. The ECU- MAF/Cats/o2 sensors probably all just aged together, and you upset that balance. I doubt reinstalling the stock intake would fix it. At 185k the cats are probably close anyway.. You also just need to do a complete systems check- particularly vacuum and exhaust leaks which could effect the sensor readings.

 

P0420 is not related to intake, it simply sees the downstream sensor swinging with the upstream. Cat is worn. Check for exhaust leaks first.

 

I just fixed my P0420 code by sealing up a small exhaust leak between the second cat and the rear O2 sensor. Definitely check for leaks before replacing cats.

 

Your PO420 code just is not detecting enough change between the front and rear sensors.

Exhaust leaks can cause this problem.

Just bad timing on this happening.

Good Luck

 

Put the airbox back on. In the long run you will be happy

 

Check engine light came back on today after I reset it on 10/31. Code this time is P0450 Evaporative Emission Control System Pressure Sensor Malfunction.

I reset the code and tightened the gas cap. It's probably the original cap and worthwhile to replace it. Anything else I should look into at this time?

 

Gas cap is no1 thing to replace or check...

IF that's not it.....most likely a leak somewhere in/around the evap system...

There's two valves that are fairly easy to check....vsv valves...
the one closest to the firewall should be clicking on/off in rapid secession all the time the engine is running...
the other one on the side of the canister is the pressure switch that controls the canister pressure...




SOLVED P0446 diagnose repair charcoal canister Toyota Tacoma √ Fix it Angel - YouTube



If its not any of that ....you may need to get/build a smoke machine to smoke the problem out...

there a ton of trouble shooting vids out there.......p0420/p0450 is very common on older tacos....

 

All that extra HP must've blew a seal somewhere

 

Ha Ha Ha Ha^^^^