P0420 and the traction light?

This morning got in and started up my 09 and the check engine light and the traction control light direct under it (the car with the swerve road symbol) were both on. The code was p0420. I cleared it and it hasn’t come back on after driving it a little but I’m wondering what is going on? Thoughts? Why would both be on at the same time, it doesn’t seem like they are connected?

 

Since traction control and vehicle stability control utilize engine cuts it's a safety mechanism to not allow these systems to make engine control modifications when there's an engine system malfunction. Therefore, the traction control and vsc may cease normal operation.

So yes, they have relation.

 

The first thing I’d do is crawl under the truck and look for signs of an exhaust leak.
It’s usually near the y-pipe at the manifold.
Since this is a 0420 code, you’ll want to look at the passenger side.
(Might as well check them all since you are under there)

If that’s not it, maybe find a buddy with a good scan tool and look at the A/F and O2 sensors.
Might as well look at fuel trims, just because it never hurts.

Hopefully it isn’t the cats, they would be the last thing I’d suspect.
I’m going with O2 sensor, but hope you get lucky and it’s just an exhaust leak.

Good luck to you

 

Same lights came on soon after I got my truck, but for an evap system problem (0456 code) so I'm not much help. Best of luck figuring it out

 

if the 02 and Af sensors read good and you dont have a crazy exhaust leak you need a cat replacement, most likely one of the front cats.

 

Ok, so the 0420 code hasn’t come back but today I got a 0456 code. Checked the gas cap, no idea what else to look at as far as “evap system “ goes.

 

I got an p0456 code recently. I believe it was a "slow leak detected" or something like that. It ended up being the gas cap on my truck. The same exact code was caused by a gas cap on my sister's t4r a few months ago. I would first check it and make sure it's tightened to the "1 click". If it feels kinda loose when you do this, it might be time to replace

If you do replace, go with Toyota/OEM

 

I may replace it just because. It’s 11 years old, can’t hurt even if it’s not the cause.

 

There are a couple threads on here that talk about it. I'm not a mechanic by any means, so I just followed their advice. To fix my 0456 code, I had to clean out the secondary air pump. The factory filter is a crappy little piece of foam that eventually starts flaking apart and interfering with stuff that's way above my knowledge level. I just cleaned it out a bit, but eventually I'll need to buy one of these: https://www.summitracing.com/parts/...LxgZrc3vkxcKqibjSAZ6tmzwQA_JJ9oBoCr8UQAvD_BwE so it doesn't throw the code again. It may not be the cause of the codes for you, but it worked for me.

 

Here's a random internet photo to show you what I'm talking about. The filter is in there.

 

I'm relatively sure my 09 doesn't have that system? I could be wrong but I think my crankcase breather hose routes air straight into the main engine air filter?

 

I have an 09 4cyl. Like I said, I'm not a mechanic. I just followed the instructions from a couple of the threads on here and the code hasn't been back in the past year or so since I did it.

 

I am pretty sure you 4.0L guys have the secondary air pump too though

 

Secondary air pump started on the v6 trucks in 2012. 05-15 4 bangers all had them

 

Gotcha, thanks for the correction. Disregard my advice OP

 

For my own information, do you know where my version routes the equivalent air? Do I have any kind of filter or is mine using the main engine air filter?

 

Yours would be missing the pump, filter, and all the plumbing too.

 

I’m not one to

This is what mine shows.
You should have the same setup as me.

 

Brand new here. So I'll just share something I learned...I live in the beautiful PNW, where it rains...ALOT! WEe just got 4 more inches of rain in 24 hours. I park on a slight incline. And sometimes, when it rains alot, the next day, I'll come out to find the 2 lights on...I have absolutely no idea why, but if you take the positive battery cable off for 5 minutes, when you put it back on, the lights go off.
Again I have no clue why it works...it certainly fixes nothing. It just shuts the lights off, until the next time it rains a ton, and I have to do it again. That's the only time it does it.

 

I don't know if this was the cause of my original issue or not but I did end up buying a new gas cap and also ran a tank with techron fuel system cleaner in it. Haven't had any issues since then. I plan on replacing my spark plugs as well, the current one's are maybe 2 years old.