URD Heavy Flywheel throwing check engine light

Hey guys,

Just had the URD heavy flywheel installed on my 2020 Tacoma, engages nice and smoothly but the ECU doesn't like it and threw a "malfunciton in the electronic control of the engine, throttle, or auto transmission (lol) has been detected". URD mentioned that the heavier flywheel should help smooth out the throttle response, so I'm sure the heavier wheel is part of it.

Wondering if anyone else has run into this after installing the part and if there's something like the throttle control I just need to recalibrate on my end, without having to resort to finding someone with techstream (like the dealer).

 

i would start by making sure everything is plugged in around the transmission. a heavy flywheel shouldnt cause it to throw any codes. im betting it has to do with something that was disconnected/removed during install. Good luck!

 

Alright I'll take a look and double check everything then! Thanks for the input

 

I know the new trucks have a lot of voodoo, but I don't think they have flywheel sensors.

Something else is amiss. Back to your installer for correction.

 

What is the CEL code?

 

Code is P0420 Cat System Efficiency Below Threshold. I cleared it with the OBD2 and it hasn't popped back up in a day now so not sure what to make of that. Could pop back up any minute now again I'm sure

 

Typically related to the downstream O2 sensor. Not a flywheel.

Could be the connection of the plug isn't good. Check the connector.

Could be an exhaust leak, since you had to remove it to remove the transmission. Look for soot around the exhaust flange for that side.

Could be that the sensor was banged too hard and damaged it.

Do the visual checks. Wait and see if the code comes back.

 

Alright thanks man, I'll do that then and report back once I've had a chance to give it another good look

 

Maybe another check point is to scan for pending codes. If this particular one is one that only pops after x keystarts with the problem, it may be in a pending status.

@Torspd do you know if that's how this code works?

 

It should be removed from pending, if all things are normal after x amount of starts and run time.

 

Well the code popped back up, says P0420 (1/1) Permanent - Catalyst System Efficiency Below Threshold (Bank 1). I haven't had a chance to look under the truck just yet, but ignition does sound a bit...different since I got it back from them. Subtle difference but could be due to an exhaust leak?

Shop isn't being super responsive so that's a separate issue I'll have to follow up on, but frustrating experience.

 

The downstream cat was probably left disconnected. That or they stole a cat and swapped it out for a hollowed out cat.

get under your truck and look for sensors in the exhaust pipe under the cab. If they’re all still connected take it to a different ship and ask them to check your cats to make sure they’re still in tact.

 

Well, looked at all the exhaust seams and didn't see any black, couldn't find any loose sensors, sat under it while it was idling to see if I could notice an exhaust leak and couldn't really hear any difference from one side or the other indicating a large leak.

Since it's only throwing the one code I'm hopeful that it's not cat related, and maybe they just did a bad job sealing it back up. Going to talk to the installing shop again tomorrow to see what they have to say

 

As others have stated make sure all connectors are not damaged and securely connected in the right places. Next move on to exhaust leaks. If you have a shop vac just blow air into your exhaust while spraying soapy water or whatever have you on all exhaust sealing areas. If still no luck move on to your downstream sensors. When I swapped out my clutch my CEL came on and it ended up being a few exhaust leaks and I fucked up one of the downstream sensors. Sensitive little buggers. I replaced all the seals and threw in a new sensor and the code went away.. Hope you get it figured out!

 

Thanks for the suggestions! I'll try that out and report back

 

You could try swapping the oxygen sensors and seeing if the problem switches to bank 2. Then it's obviously a faulty sensor.

 

Well I think it's sorted, y'all. I went under the truck and just tightened every bolt I could find on the exhaust, and the bolts holding in the passenger cat were probably looser than finger tight. Shop must have just missed them. Cleared the codes, driven about 50 miles since then over the past couple days, no code showing back up.

Feeling good about this being in the past, thanks for all the suggestions in this thread! Always know I can come chat with y'all about things to get good feedback.

 

Easy fix. We'll done.

 

if it comes back on this is an emmission related code... should be 7 years 70k mile warranty. I wouldnt tell the dealer that you put on a heavier flywheel as they might "kick it" as a modification.