Hello, I have a 2015 Chevrolet Silverado 5.3L with 141,300 miles on it. I bought the truck used from a dealership, they did replace the transmission that came with a 4yr warranty. The first day I had it the check engine light came on. I used my OBD2 to check for codes and got P0420 & P0430. I called the dealership Milnes Chevrolet in Imlay city Michigan were I bought it and they replaced both catalytic converters. They had another garage do it for them and we split the cost. So I paid $400 out of my pocket. 2 days later the check engine light came on again and it only showed P0430 code. So I took it back and they looked at it again and said something didn’t get cleared on the computer, no charge to me. Then 2 days later it happened again with the same P0430 code. So they replaced the passenger side catalytic converter, no charge to me. It ran with no check engine light for about 3 weeks. Then I got the P0430 code on Sunday then cleared it and it showed up on Tuesday same thing. I need to find someone I can trust to look at my truck but I don’t want to go to anyone without having some idea what is going on. Do you know of anything that could be causing the problem or something I could check? The truck doesn’t run ruff or sound off. I am a little mechanically inclined. Thanks.
Well, I checked this site,
https://repairpal.com/obd-ii-code-p0430
and from what it says, I think you should have an INDEPENDENT mechanic check for a head gasket leak and do a compression check.
Common Problems That Trigger the P0430 Code
- Defective Catalytic Converter
- Internal engine damage resulting in high oil consumption and/or a leaking Head Gasket has damaged the Catalytic Converter
Common Misdiagnoses
- Oxygen Sensor(s) are replaced when the real problem is a damaged Catalyst
- Catalyst is replaced when the real problem is internal engine damage, which is producing elevated emissions levels
- Catalyst is replaced when a misfiring engine is the real problem
Those dirty scumbags. You should never have paid anything.
Sounds like coolant or oil may be getting into the exhaust, I had a CCV valve in a 1994 BMW 540i go bad once. It caused a vacuum leak that was so bad my exhaust spewed smoke like my rings took a hike, and I smelled oil burning. There was also an obnoxious squealing sound that sounded like a giant rubber chicken. It ran fine, but I got quite a few looks from people... lol. The service engine light indicated an O2 sensor problem, that was it. A shop was going to charge $400 to replace the O2 sensor, they didn't see anything else wrong. I found a vacuum leak spraying starter fluid behind the intake manifold when the engine was running. I explained the location to a BMW dealer, they said it needs a CCV valve and they ordered it. I replaced it, and all the problems went away. The service engine light went out after about 20 minutes of driving, and the noise went a way immediately.
Check your oil and coolant levels and keep an eye on them. I would check for vacuum leaks, they probably aren't as severe as mine was, but they can cause oil consumption. Check your PCV valve. That does the same thing as my old BMW's CCV valve, and I recently had an issue with a shop not reinstalling mine in my Ford Ranger a couple months ago. I discovered milky residue on my oil filler cap, which caused me to suspect a head gasket problem. Everything checked out, but I found the PCV valve hanging out of its hole on the valve covers. I replaced it, and everything went away.
Unfortunately places like to throw parts at problems that aren't the source of the problem, hopefully my little story is encouraging, it could be simple! Good luck figuring it out!
