I have a 2018 F-150 STX with 34K miles and the check engine light came on yesterday. I checked the code, and it’s P0430. A couple of months ago, my mileage dropped about 1-2 mpg, and last month while driving at speed, the engine seemed to hesitate a few times before going back to normal. This only happens sometimes, but it’s been happening more frequently. Could this be a fuel injector issue, bad gas, or maybe a dirty mass air sensor? I’m hoping someone can steer me in the right direction. TIA!
P0430 is a catalyst system efficiency below threshold for the left bank.
The rear O2 sensor is detecting something off with the catalytic converter. You might want to check the O2 sensor signals with a scanner to see if one of them is going bad. It could be the cat itself, though—sounds like it might be clogging, which matches the hesitation you’re describing. Also, catalytic converters are covered by an 8-year/80k-mile emissions warranty, so that might help you out.
The P0430 code usually points to issues with the catalytic converter, but there are several possible causes. It could be a damaged O2 sensor, exhaust leaks, or even a misfire. I’ve listed some possible causes below:
- Damaged heated oxygen sensor
- Exhaust leaks
- Damaged catalytic converter
- Leaking fuel injector
- Cylinder misfiring
- Oil contamination of the catalyst
Definitely worth checking all of these.
Sounds like the substrate in your cat could have broken up and is now partially blocking the outlet. That could be causing the high backpressure on that bank and messing with the O2 sensor. The sensor’s action might be off, leading to the P0430 code. Check the rear sensor’s voltage swing compared to the other bank. If it’s different, that could point to a failing cat. This should be covered under warranty if that’s the issue. Good luck!
Welcome to the forum! It’d help if you put your truck info in your signature so people can give more tailored advice.
If it’s the catalytic converter, it’s covered under an 8-year/80k-mile warranty. Just take it to the dealer—they should replace it for free.
Another one posted and hasn’t come back yet, looks like they’re not super worried about it. But yeah, sounds like they’ll need to check that cat and sensors. Let’s see if they respond.
If you’re seeing hesitation, a misfire could be pushing unburned fuel through the exhaust, which might be why the cat’s deteriorating. Might want to run a full OBD scan to catch any other codes, too.
Be ready for a long wait for the new cat if it turns out to be the issue. My dealer’s been waiting six months for one on my 2019 with P0420/P0430 codes.
Wow, that’s crazy! My replacement cat came in 5 days, no wait at all. Seems like it really varies!