P0420

BC

Full Member
Joined
Jun 28, 2007
Messages
130
Likes
0
Points
16
#1
Make
Toyota
Model
Tundra
Year
2003
Miles
315K
Engine
4.7
P0420 Catalyst System Efficiency Below Threshold Bank 1.

So with this code coming on intermittently, I thinking the catalytic is probably getting old and tired like me! Truck has 315K on it with regular maintenance including tune-ups.

These are very expensive to replace so what if... Or could I... replace with straight pipe and then somehow reprogram the ecm to keep the code from appearing? Or is this a loss cause? Trying to figure out a way around replacing them of course.

Thanks
 

kev2

wrench
Joined
Nov 14, 2006
Messages
4,785
Likes
46
Points
48
Age
118
#2
unlikely it will work -
AND it is illegal .

suggest you trouble shoot cat code- often another issue causes the intermittent codes.
A look at precat o2 sensor- fuel trims, etc....
 

BC

Full Member
Joined
Jun 28, 2007
Messages
130
Likes
0
Points
16
#4
Ok, 10-4 on the legalities.

The O2 sensors are all fairly new. Whats the method of checking the fuel trims out?
Thanks
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
8,556
Likes
137
Points
63
Location
St-Hyacinthe, Quebec, Canada
#5
replace with straight pipe and then somehow reprogram the ecm to keep the code from appearing? Or is this a loss cause? Trying to figure out a way around replacing them of course.
This would be very difficult. Reprogramming the algorythm for a straight pipe, no. But you can install a cheater.

Yes it is illegal but you don't need to remove the cat, cuz that will cause you problems at time of inspection. This is a viable solution I used back when I was living in ontario. There they have mandatory testing, up here, we simply just don't care.

To fool a PCM, you need access to mode 6, coding skills etc. For a few $ this is way more viable and prone to actually work. It has worked for me many times in the past.

But to cheat, it is quite simple, all you need is a few soldering skills. Some resistors, a capacitor and presto. So just remove the offending cat, use a broom handle or whatever, reinstall and cheat the PCM with this video that should exlain what I am trying to say.

I may get grief from collegues here, but really, one more polluting car in the PPM dept is not going to change sweet f all while our countries devastate forests pass laws that prevent going full electric from lobbying aristocrats.


.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
8,556
Likes
137
Points
63
Location
St-Hyacinthe, Quebec, Canada
#7
On my own personal car, my check engine light has been on since I bought it, scanned it, p0420, and I don't care, have not seen any performance issues.

Although I did use an old tech trick, I fueled with diesel in small shots. My cat got hot enough, it got so hot, it burned off all impurities causing that pesky code. The code went away for a full two months. Came back last week, same code, time to fuel some diesel in my rice burner echo. ;)

Men in my trade have many tricks. Just want to knopw how far you want to go. Cuz I bought my rice burner for 200$. No way in hell I am going to spend $$ on a cat that I can put on my futur 335 beemer twin turbo project.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
8,556
Likes
137
Points
63
Location
St-Hyacinthe, Quebec, Canada
#8
Fuels trims are quite easy. Anything over + or - 10% is suspect.

For a p0420, fuel trims are not important. They will always be out of whack. So either you cheat, then use trims to fine tune the rest, but you can't do that with a bad cat. Hope that answers this question.
Whats the method of checking the fuel trims out?
 

BC

Full Member
Joined
Jun 28, 2007
Messages
130
Likes
0
Points
16
#9
Ah thats what I'm looking for...Thanks! Yeah we don't have inspections here in FL so I don't have to worry about this part. And I totally AGREE with you on the emissions. I just wonder what one diesel truck is equivalent to in the smog world compared to how many of vehicles like mine? Or one of the so called emission friendly TDI Volkswagen? Believe me... I don't feel bad. If they are so worried about this then why not have a Gov program to reduce the cost of these very expensive cats? I'll find something else to spend my $$ on. Thanks!!
 

BC

Full Member
Joined
Jun 28, 2007
Messages
130
Likes
0
Points
16
#11
Damn, wish I was there drinking with you all! Thanks nickb2 & Kev for sticking your neck out to show me this info. I'll try this out and report back as suggested.
This will be a good solution for my off road Tundra farm use only vehicle :)
Thanks!!
 
Last edited: