Randy O'Quinn

Just over 100k miles. I changed the plugs, keep up on my oil changes, all the o2 sensors have been replaced and are reading good on heated catalyst test. Just had the fluids changed at 80k miles as well.

Your saying probably the converter again but what about the other codes? The U codes coming up in the ECM, BCM, ect. They are all communication codes. Can a insufficient catalyst reading cause communication issues between the modules and the catalytic converter?

Yeah.... I wanna fix the problem tho. Both sensors are new and it did it with the old ones. I know I can get the spacers but I have emissions every 2 years and I don't want to fail.

So, I have a 2014 Sierra 5.3 and I've had the P0430 bank 2 issue. I replaced the stock cat with the Walker aftermarket one and after 3 months the code came back up. I was able to have the Walker cat warrantied and got a Magnaflow one this time instead... Thinking it may have been the Walker cats. After breaking in the Walker cats I have the code popping back up along with other codes as well. I have changed the spark plugs, checked the oil and coolant for possible contamination, checked for exhaust leaks, ect. I'm about at my wits end and I'm hoping someone has some info that could possibly help me. I have enclosed screen shots of the codes that came up on my scan tool.