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2003 Toyota Tacoma - OBD Codes P0420, P0441, and P0446


Topic starter

Hello all! I recently bought a 2003 Toyota Tacoma double cab 4x4 with an automatic transmission and 193,000 miles used from an auto auction. I got it and I noticed that it had a check engine light on. I plugged in an OBDII scanner and it showed the following codes:

P0420 - Catalyst System Efficiency Below Threshold Bank 1

P0441 - Evaporative Emission System Incorrect Purge Flow

P0446 - Evaporative Emission System Vent Control Circuit

The only mod on the truck appears to be an AEM air intake (AEM-21-8402DP) Can anyone help me out? Thank you.

4 Answers

It would usually be a bad cat. 

But with those other codes, I am not 100% certain. So many emissions things to deal with. The problem ccoild be upstream from the cat. Or downstream from the EVAP codes. 


this is why you inspect and scan codes BEFORE paying money.


Topic starter

@MoutanManJoe Absolutely! I got the car from a Copart auction about 400 miles away though so unfortunately that wasn't an option... It was a very low price however, so I did expect for there to be something wrong with it, and, well, I was right, haha! Thank you for your reply!

Topic starter

@kaizen Thank you for your response! Will look into that.