TRD/ Magnuson 4.0 Supercharger Tips, Tricks, and Mods

It is downstream. +1 to this.

 

So should I just not do nothing because I’m switching to longtubes and hp? If I do the sensor swapped to try to replicate it, is it the 2 rear sensors (the ones plugged into the y-pipe?)

I always get confused. The way I’m understanding it is the front 2 sensors are flow sensors and the rear 2 are the o2 sensors.

 

P0420 is a pretty harmless code. Get the long tubes and HPtuners installed. They are great mods

 

both are o2. The ones just after the exhaust valves existing the engine are also called upstream since they are before or upstream of any converter and get an untainted registration of the exhaust. The ones after the first set of cats are sometimes called downstream. Not all vehicles have multiple sets of cats. The downstream tell you how well the cats are working for obvious reasons. The upstream are what your engine makes adjustments off of for fueling and efficiency in general terms.

 

Gotcha. So then to check cat vs sensor to replicate the code, am I doing this downstream or up?

 

this is a downstream code, after cat. Minor issue. Swap them in the y-pipe to confirm if it is the sensor or the cat.

 

To complement for clarity for all, the front ones (pre-catalytic converters, and also AKA upstream sensors) are named WRAF sensors. Wideband Ratio Air Fuel sensors. Piezoelectric sensors.

 

I’m also pretty sure the UCOM EMS allows one to not worry about o2 sims as the UCON does all the calculating and sends fade data to the OEM ECU.

someone can verify or fact check me haha

 

Get rid of it!!!

 

Upstream yes, downstream no

 

???I'm running UCON, no sims here. Up and down present. Catless headers and Y-pipe. I added Hi Flow cat after Y pipe.

 

Them I stand corrected. It must piggyback both altogether.

 

I had thought the downstream ones could be removed when I original installed the UCON. Figured they just checked the condition of the cats and could be deleted/ spoofed in code, but ended up having to reconnect.

 

per Gadget at URD you still need the secondary o2 sensors for the system to function properly. Even though youehave sims there is still feedback the ecu needs.

 

A note about sims VS using hptuner software to disable the CEL. If you use sims you will pass an OBD2 emissions scan. If you disable the check engine light then the monitors will read as not ready, which is no good for places like California. YMMV so just throwing that out there.

 

Yup.....I get 1 “incomplete” or “not ready”. That will be used on the Sai

 

Thank you! This is correct.

There is also one more option (which is of limited practical use). You can disable the CEL from illuminating if the code pops up, and still keep the monitors functioning. However, if you do trip the code you'll still fail for obvious reasons but you won't have to have the light glaring at you.

 

you mind taking a pic of your headers/cat/ypipe set up?

 

as i understood the sims worked well unless you have a 2015 truck. can confirm they did no help on mine. id just go hp tune for said solution.

 

Sims didn’t work for mine either