DTC P0420 - Check Engine Light for Catalytic Converter

[redone17]

Reading into this - it seems that perhaps just having the catback exhaust for 2 years + short commute may be the underlying issue.

Magnaflow has their upgraded converter coming soon.

I just wonder if I will get this covered. My dealer has been great to work with. But, I can see them pointing fingers.

I guess I can reinstall the stock exhaust…

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[redone17]

I can’t get it in for service until 12/19. So, I’ll report back then.

I’ve been meaning to install a block heater to mimic operating temps for the short commutes. I guess it’s time to take care of that.

 

[Rob_Broncowski]

Have you crawled under the truck to take a look at the cat? I think the solutions posted above are the most likely cause but I would also want to rule out damage due to an attempted theft.

 

[redone17]

Have you crawled under the truck to take a look at the cat? I think the solutions posted above are the most likely cause but I would also want to rule out damage due to an attempted theft.

Yeah, looks sound to me. I’ve got a decent amount of mud on the truck too - and no hand/glove prints to speak of. It was definitely my initial concern since it was part late night in NYC when I first got the light on the way home.

Assuming I’m looking for saw marks or otherwise?

 

[Ford Motor Company]

I’ll post more details when I can scan for codes tomorrow. But, haven’t heard anyone having the issue yet.

Well, I hit 30,000 miles and got home late last night and had to head out of town all day. I will report back tomorrow once I can scan DTCs. I was parked in NYC and thought perhaps it got tampered with - but I didn’t see any signs upon quick inspection. No noises/sounds, power issues, etc and running fine otherwise.

Any input on what to look for/check is appreciated. Any chance this has something to do with running NGK step colder plugs with the FP Tune?

Hey there! If you send over a DM with your VIN and Ford dealer info, I can look into your concerns on my end.

 

[Rob_Broncowski]

Yeah, looks sound to me. I’ve got a decent amount of mud on the truck too - and no hand/glove prints to speak of. It was definitely my initial concern since it was part late night in NYC when I first got the light on the way home.

Assuming I’m looking for saw marks or otherwise?

Good to hear. Yeah I was thinking maybe someone tried to steal it and got scared off before they could finish the job. I would imagine there would be some cuts if that were the case.

 

[redone17]

Funny thing…I got in my truck to leave work this evening and the check engine light is off. I put in a large bottle of Techron in 200 miles ago. Code is still in the system, as expected. But, I’m wondering if the O2 sensor was just gunked up or something.

 

[JL8jeff]

I had 99 Tacoma that would pop up the light for a catalytic efficiency code after a longer drive (1 hour +) and I would manually clear it and it would be fine for months before it showed up again. I think I found a spark plug was so worn down (120K miles on them) that the gap was too big and eventually led to the code. So a lot of times it has nothing to do with the converter but the ignition, gas, fuel, sensors can cause the issue. I wonder if you're getting a little bit of oil blowby into the exhaust which could affect the cat.

 

[redone17]

I had 99 Tacoma that would pop up the light for a catalytic efficiency code after a longer drive (1 hour +) and I would manually clear it and it would be fine for months before it showed up again. I think I found a spark plug was so worn down (120K miles on them) that the gap was too big and eventually led to the code. So a lot of times it has nothing to do with the converter but the ignition, gas, fuel, sensors can cause the issue. I wonder if you're getting a little bit of oil blowby into the exhaust which could affect the cat.

I’ve had a UPR catch can installed since 8k miles. I knew having short commute would cause problems down the line. At one point I had a vacuum code at the throttle body that cleared and never came back. I’m thinking I really need to stop putting off installing the block heater. It’s been sitting in my garage for two winters along with the coolant pressure kit…

 

[Mojua]

I have a completely stock '23 WT. Got it in May. My check engine light came on in July. Ford Pass app notification said the same thing it told you. Brought it to my dealer. They immediately said the CC was shot, or something to that effect, and said they'd order a new one for me. Took 3 months for them to get the new CC. Drove perfectly in the meantime. I finally got it installed a few weeks ago. Was covered of course, but I saw the invoice; $2800 for parts and labor.

 

[redone17]

I have a completely stock '23 WT. Got it in May. My check engine light came on in July. Ford Pass app notification said the same thing it told you. Brought it to my dealer. They immediately said the CC was shot, or something to that effect, and said they'd order a new one for me. Took 3 months for them to get the new CC. Drove perfectly in the meantime. I finally got it installed a few weeks ago. Was covered of course, but I saw the invoice; $2800 for parts and labor.

My dealer has been great to work with, but mine is far from stock. Hope they don’t give me any slack about that.

 

[redone17]

So, I’m getting a new catalytic converter installed under warranty along with a slew of recalls that aren’t even showing up as pending when I login. Wasn’t even aware of them.

Even though it says I got the software update for the 4L camera - they’re stating it wasn’t completed. Which is weird to me because the rear camera turned off - albeit only after I pick up some speed. So, maybe it wasn’t working as intended.

The recall on the wiper motor - didn’t realize that pertained to my VIN and one other…I can’t remember what he said.

I’ve put off installing the block heater for the past two winters - just never got around to it. I have the correct socket and the coolant pressure/purge tool - but, they quoted me $130 (and I have a $25 holiday coupon from my dealer). So,
I’m taking advantage of them having it on the lift.

I hope setting it on a timer on days I know I won’t be driving much more than my 2 mile commute will help alleviate future issues.

 

[redone17]

That being said, I’m also gonna plan to drop in a bottle of Techron every 5k oil change or so - since after 200 miles it seemed to have cleared the code. I’ll get as much info/details as I can from the tech tomorrow.

 

[redone17]

So much for $130 to install the block heater…$210/hr and 3+ hours…I got them down to $500. Next time I’ll get the quote on paper. Lesson learned. But, it’s done. So, that’s great. Seems like it was a pain to route the cord with all of the clips in the factory locations. I was trying to dig into the service manuals for that info. I’m glad they got it done. But, $100 from factory vs $800 after the fact…

Catalytic Converter is on order. They said 7-10 days. I’m scheduled for January 5. We’ll see. Perhaps I’m looking too deep into the cause - because my advisor said there was a bad batch and that I’m not a first. Looks like they performed extensive tests and it failed. They also checked for exhaust leaks, which thankfully there weren’t any. I’m glad they didn’t give me any slack for the Magnaflow exhaust.

Wiper Motor & Software TSBs are done too…

 

[JFelty]

Mine Check Engine light has been coming on intermittently as well. I have the the Ford tune installed and the tuner lets me read the error messages. The only one it has ever thrown off is "P0420 Cataleptic system efficiency below threshold (Bank 1) so it went to the dealer this morning and I just got the call that my CC is bad and that they are covering under the powertrain warranty. My question is how and or why do they die so quickly? I have 44K on my 22 Wildtrak (yes it is driven quite a bit 60% highway and 40% off road).

Regardless it will be in the shop for 2-3 days :-(

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