Need some advise 2021 Expedition 33,800 miles P0430 code dealer has replaced the cat and the code came right back after driving off the lot. Now they are going to replace the same cat again. But what could actually be causing the issue. The only code is the P0430 could there be a miss fire that the computer is not detecting I know in older fords they would not show a miss fire code unless it did it a lot. The driver side turbo waste gate sounds like it has a rattle at cold start which they are saying is normal. It seems to drive fine. If the cat is replaced again and the light still comes on what is normally the root cause at that point? There was a P0316 code that was stored in the memory that could have been old but was not causing the light to come on it was cleared and hasn't shown up since but the P0430 code has stayed constant even after replacement it has come on now 3 times with in 40 - 50 miles of it being cleared even after the cat replacement. Currently the dealer is saying the new cat could be bad that they just replaced yesterday.
2021 Expedition P0430 code before and after cat replacement need some advise.
- Thread starter 03Cobra
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99WhiteC5Coupe
Full Access Members
My best advice - the vehicle is under warranty and it is Ford’s problem to diagnose and fix. Let them keep replacing parts until they figure it out.
Left Coast Geek
Full Access Members
For sure, I would be looking at the odbc realtime data from all 4 Ox sensors to verify they are good. The downstream sensor on the side of the suspect cat should show some sort of anomaly... But yeah, it's the shop's problem
Sounds like your dealer is just launching the parts cannon at it. Plus they are on warranty rate, so they are probably rushing. Maybe they will eventually strike gold. If it were me, get a new dealer.
I was a dealer tech in a past life. Still wrench on the side. A good tech knows that catalytic converters don’t typically just go bad on their own. There is usually an underlying cause. Usually started with bad air fuel ratios which can be from false O2 sensor readings, sticking injectors, intake gasket leaks, misfires from plugs/coils, or bad gas. A good data log on a good scan tool can determine this stuff very easily.
I was a dealer tech in a past life. Still wrench on the side. A good tech knows that catalytic converters don’t typically just go bad on their own. There is usually an underlying cause. Usually started with bad air fuel ratios which can be from false O2 sensor readings, sticking injectors, intake gasket leaks, misfires from plugs/coils, or bad gas. A good data log on a good scan tool can determine this stuff very easily.
Ugh_J
Member
Agreed. When my 2020 threw that code, watching the 4 sensors showed 3 were very stable even sub-1000 degrees, but the 4th (downstream bank 2 if I recall correctly) was showing a good bit of fluctuation. They replaced the cat on that side (mine was bank 2) and never had an issue after that.
ZigZagFred
New Member
When troubleshooting, it's usually a good idea to start replacing parts with the cheapest ones first, and then work your way up the price ladder. I would be suspicious of a shop that wanted to replace my cat TWICE without changing anything else first. Cats are expensive.
Left Coast Geek
Full Access Members
1) Avoid parts shotgunning entirely. there's no guarantee 'new' parts are actually good, even if they are dealer bought Ford brand parts. At least, if you put in a new part and there's no change of symptoms, take note and replace the original part ... Absolutely avoid aftermarket and especially Amazon/Alibaba kinda parts, except specific brand name substitutions such as NGK spark plugs.
2) get on youtube and watch a bunch of eps of Pine Hollow Auto Diagnostics, and South Main Auto LLC. Both these guys demonstrate good diagnostic troubleshooting techniques
2) get on youtube and watch a bunch of eps of Pine Hollow Auto Diagnostics, and South Main Auto LLC. Both these guys demonstrate good diagnostic troubleshooting techniques
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