HELP !! P0430 code

Discussion in '2011+ Mustang GT 5.0L Tech' started by Steven210, Aug 3, 2022.

Tags:
  1. Steven210

    Steven210 Junior Member

    45
    6
    Recently my 2011 mustang Gt has been tripping the P0430 code. I first checked for leaks. I replaced the exhaust clamps since they were loose regardless of how tight I torqued them. No luck, code came back. I then replaced the downstream O2 sensor on bank 2 thinking it would solve the issue. Nope, code came back. With 216k miles on it, I figured it was the cat. Replaced it and still the code returned. The cat was a Walker from rock auto. I then don’t replaced the upstream O2 sensor, spark plugs and the cylinder head temperature sensor. Still no change, the code comes back. Not sure what could be causing it.

    Anyone have any ideas what it could be?
     
  2. jewc75

    jewc75 S197 Junkie S197 Team Member

    20,151
    1,221
    Is the car tuned? What fuel are you running?
     
  3. Steven210

    Steven210 Junior Member

    45
    6
    It hasn’t been for at least 2 yrs. It had a bama tune at one time but then I returned it to stock. I used to always run 93oct but when gas prices got crazy I started using 87. Now I’m back to 93.
     
  4. jewc75

    jewc75 S197 Junkie S197 Team Member

    20,151
    1,221
  5. Juice

    Juice forum member

    4,215
    1,658
    Based on my personal experience, these coyotes (11-14) are super sensitive when it comes to the cat tests.
    Some aftermarket cats may not pass the self test.
    What is interesting, you are only getting the 430 code. (One side only).
    This is not going to be a simple fix. I recommend getting Forscan to access mode 6 data to start. Going to have to dig into this one.
     
  6. Steven210

    Steven210 Junior Member

    45
    6
    Thank you for your feedback. I was wondering if the aftermarket cat would still trigger it. And not sure why only one side
     
    Last edited: Aug 4, 2022
  7. pass1over

    pass1over I like it LOW

    Age:
    42
    1,151
    95
    I had a P0430 code, but it followed banks when I swapped the rear o2 (and went away when I had them disabled, lol). In my case, it was that faulty downstream sensor. Are you 100% there are no exhaust leaks on bank 2?
     
  8. Steven210

    Steven210 Junior Member

    45
    6
    I can’t say 100% but I’ve double checked the exhaust clamps. The only thing I didn’t change out was the gasket between the cat and exhaust manifold.
     
  9. Juice

    Juice forum member

    4,215
    1,658
    I think my catalyst monitor completed twice in 5 years.
    I am blessed/cursed with that one and the o2 sensor monitors not completeing, no fault codes. Even with a bone stock tune w/factory airbox. lol Being exempt is a blessing.
     
  10. pass1over

    pass1over I like it LOW

    Age:
    42
    1,151
    95
    This is the best way I've found to check for sure. I stick a leaf blower into one tailpipe, seal it off with rags and ratchet strap/bungee cord it in. Then I shove bunch of rags into the other exhaust tip. Turn the blower on and feel/listen for leaks. I've also found a long reach lighter, like a bbq grill one, can help searching for small leaks around gasket surfaces. Just move the flame around it briefly, you'll know if there's a leak or not as it will blow the flame around.

    I do this on my lift, so YMMV if your on the ground/jack stands.
     
  11. Steven210

    Steven210 Junior Member

    45
    6
    Thanks for that technique. I’ll have to give it a shot.

    This code is driving me crazy, making me wish I ran straight pipes lol
     
  12. Juice

    Juice forum member

    4,215
    1,658
    Do you have to have smog inspection?
     
  13. Steven210

    Steven210 Junior Member

    45
    6
    That’s a good thing. I don’t have to
     
  14. Juice

    Juice forum member

    4,215
    1,658
    You could have it tuned and have the code disabled.

    How are the LTFTs between the two banks? They should be within a few %. Personally, Im ok with 5% or less.
     
  15. Steven210

    Steven210 Junior Member

    45
    6
    asked everyone and no one I know has a leaf blower lol. Still double checked the exhaust connections. I did go and check the hoses and connections going into the air intake and manifold. Noticed the valve cover bolts we loose, so I torqued them back down. I also Cleaned the MAF sensor again. I Noticed the PCV hadn’t been changed in a long while so I replaced it. Let’s see what happens
     
  16. pass1over

    pass1over I like it LOW

    Age:
    42
    1,151
    95
    I was thinking about this on the drive into work today. Could you possibly have 1 or more injectors on bank 2 that are getting clogged tips or lazy? Would that even throw a code for injectors or anything?

    Could you switch all injectors from bank 2 to bank 1 and see if the lean condition follows?
     
  17. Juice

    Juice forum member

    4,215
    1,658
    It wont throw a fault until it got bad enough to misfire. At first, the fuel trims would adjust, and you would have an increasing difference between banks.

    Yes, you can swap injectors around.
     
  18. pass1over

    pass1over I like it LOW

    Age:
    42
    1,151
    95
    Which is why you asked about fuel trims .... makes sense. Checking datalogs would be easier than swapping the injectors.

    I know you can swap injectors. It was more of a question to the OP, if he was comfortable doing that or not.
     
  19. mustangGT90210

    mustangGT90210 Junior Member

    8
    0
    On many modern cars, they don't take well to aftermarket cats. Just like Ford vehicles don't enjoy running with aftermarket alternators, same idea

    Replace the cat with a Ford part, get the code tuned out of it, or just ignore it lol
     
  20. Steven210

    Steven210 Junior Member

    45
    6
    I can do that but I was thinking, would clog filters cause a misfire code?


    the only thing about checking the datalogs is I’m not sure what to look for.
     
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.