Last reported case: 1 months ago
Based on 6 owner reports (1 from Reddit, 5 from forums)
What is P0420?
P0420 indicates your catalytic converter is not cleaning exhaust gases effectively, typically triggered by a failing converter or upstream engine issues. This powertrain code is moderately serious and can affect emissions and performance, with Honda vehicles like the Accord and CR-V appearing most frequently in reports. Based on 975 repair cases, the average repair cost is $3847, ranging from $0 to $4700.
Common Causes:
- Failing catalytic converter (most common cause based on code definition)
- Upstream oxygen sensor malfunction
- Exhaust leaks before the catalytic converter
- Engine misfires or rich/lean fuel mixture affecting converter efficiency
Symptoms:
- Check Engine Light illuminated (primary symptom)
- Reduced fuel economy reported by some owners
- Possible lack of power during acceleration
- No noticeable symptoms in some cases beyond the warning light
🚗P0420 on 2010 TOYOTA Tacoma
This page focuses specifically on P0420 issues reported by 2010 TOYOTA Tacoma owners. The experiences and fixes below are from real owners of this exact vehicle.
Symptoms Reported by 2010 TOYOTA Tacoma Owners:
Parts Often Involved:
What Owners Say
Real experiences from 2010 TOYOTA Tacoma owners
“2001 3.4L Tacoma P0420 Help Hey ya'll, Texas native, with this ice storm that just hit I was happily using my 1st gen in 4x4 for the first time in a while, driving home from an errand when I got a CEL, P0420, pop up when I got back into my neighborhood.”View original
“So I assumed this was the exhaust leak come to haunt me and got some exhaust putty and went to double check the leak today. I noticed it is barely there if at all.”View original
“So when those codes began popping up, my heart sunk, because I knew it meant I would need to do the $3000+ manifold converter replacement. You may be thinking those manifold cats don't cost that much, and they don't... everywhere in the world EXCEPT California.”View original
“When the front was jacked up it also wouldn’t start till on level ground. Possibly unrelated on two occasions on 3 hour road trips the battery warning light would turn on and once died on me but these incidents were about a year apart and possibly a symptom of the previous owners shotty diy wiring for sound system and kill switch but felt it was important to mention just incase.”View original
“I do not agree with CA's draconian smog law that requires the use of such expensive converters to achieve a minimal improvement to emissions. Its akin to requiring every person who wants to drive, to purchase and wear a $3000 platinum ring.”View original
“Oil on the spark plug - could that be making a P0420 worse? 2006 TRD OR 4.0 Automatic - very minimal rust - I bought in California, wrecked it and rebuilt it myself So I've been battling my P0420 again.”View original
“P0420 truck not starting: This is my first post so sorry if my formatting is weird but my 2006 base model Tacoma popped the P0420 code and after replacing multiple parts it longer starts.”View original
“2006 TRD OR 4.0 Automatic - very minimal rust - I bought in California, wrecked it and rebuilt it myself So I've been battling my P0420 again. At best I've gotten it to go away for a couple months but now it seems to be coming back every other week.”View original
“I also switched to 93 octane fuel. Here is a vehicle scan with live data. https://resources.repairsolutions.c...8ee-4fb5-8d2a-18e9eb928761_03192025100240.pdf”View original
“Good morning, I need help, and my patience is running thin with my first gen. My truck is a 2003 2.7 4x4, and for the last couple of years I've had nothing but issues with this code.”View original
These are real experiences shared by 2010 TOYOTA Tacoma owners on automotive forums and communities. Results may vary based on vehicle condition and repair quality.
About This Data
This page aggregates 6 discussions about P0420 from 2010 TOYOTA Tacoma owners across automotive communities.
Success rate (50%) is calculated from posts where owners confirmed whether their fix resolved the issue.
Last updated: 1/26/2026