2010 Aveo - P0420 Code Tried Everything Please Help!

[Jesswilliams80]

Hello!

I purchased this 2010 Chevy Aveo for my Dad in April. It had no lights on, low mileage, and seemed like a nice little car, for the first two weeks. After that, it's been a sea of codes, troubles, and aimless replacements of things that aren't helping the cause. I'm in desperate need of fixing this, as it's due to be inspected at the end of the month. I'm going to list the codes I've received and the things that I've replaced, and if anyone has any insight, I'd be beyond grateful to hear it.

P0420 Catalyst System Efficiency Below Threshold Bank 1
P0137 02 Sensor Circuit Low Voltage Bank 1 Sensor 2
P0341 Camshaft Position Sensor "A" Circuit/Range
P00B7 Engine Coolant Flow Low/Performance

For code P00B7, I discovered I had a missing O-Ring in my coolant cap, and replaced the cap. Also did a coolant flush, and replaced the thermostat housing assembly, and throttle body heater inlet pipe (I think it broke in the changing of the housing).

Then P0341, P0137 and P0420 have been my stubborn codes.

I've replaced the Crankshaft position sensor and Camshaft position sensor. Replaced the 02 sensor upstream and downstream, replaced the manifold catalytic convertor, and the rear catalytic convertor. Changed spark plugs and wires, ignition coils,

It had some hesitation in the brakes, and a stiff pedal, so I replaced the Brake Booster and the brake booster vaccum hose. It has new brakes and I'm still not seeing any improvement. The TPMS light is on, so I got new sensors, and the airbag light keeps coming on and going off, it's an intermittent issue. This car has been a special case to say the least. It doesn't have that many miles on it, when it's not lit up like a Christmas tree it seems to be a nice riding car. I'm at a loss.

I don't know if these are related or separate. But I do know that I'm at my wits end over the P0420 code. I don't know what else to try. I even read something in the forum about trying a spark plug non-fouler with the 02 sensor and we've tried that with no luck as well.

Any suggestions?

[avguy]

.... Any suggestions?

You described all of the part-hanging that you've done, but not a word about diagnosis. Have you tried reading the the OBD data stream with a realtime reader? If not, then that would be my suggestion.

[Jesswilliams80]

My apologies. Yes, I have read the OBD data stream with a realtime reader for the O2 sensors. I am getting good readings on the O2 sensors, but still the code suggesting to replace them. At first I did not, and replaced my downstream with a OEM replacement, as I had an aftermarket on the downstream, because it was what was available when I purchased them. I thought that may have been the issue, after reading more comments to other posts on the forum. I've checked for vaccum leaks in the exhaust that may be triggering the code, but no luck. Everything seems fine.

[avguy]

What are the fuel trim values? One guy resolved a second gen Aveo P0420 by replacing the injectors, so if your vehicle is running on the rich side, it might be worth trying to remove and clean the injectors and install new O rings. But first try a bottle of Techron to see if that helps at all.

[offroad4x4]

same issues with codes checked every thing any luck with might be it ...is it a issue from the factory thanks

[Jesswilliams80]

Sorry Offroad4x4, I never did resolve the issue. We put over $4k into it trying our best to not junk it, from catalytic converters, exhaust, multiple rounds of O2 sensors, ignition coils, fuel injectors, cam shaft and crank shaft sensor, mass airflow sensor, spark plugs, fuel caps, thermostat and housing, etc. This code kept spiraling. It would never go away and the OBD scanner would give us a wild goose chase of items to try and repair. It was a Beautiful car from the outside, with low miles! But at the end of the day it Out of nowhere blew a head gasket and overheated. I’m guessing it was probably the issue all along but I can’t say for sure. Couldn’t get the engine to crank so it wasn’t worth rebuilding and couldn’t find a rebuilt to purchase, only used. Didn’t want to go through it again so we junked it for a measly $150.

[Deano]

Sorry Offroad4x4, I never did resolve the issue. We put over $4k into it trying our best to not junk it, from catalytic converters, exhaust, multiple rounds of O2 sensors, ignition coils, fuel injectors, cam shaft and crank shaft sensor, mass airflow sensor, spark plugs, fuel caps, thermostat and housing, etc. This code kept spiraling. It would never go away and the OBD scanner would give us a wild goose chase of items to try and repair. It was a Beautiful car from the outside, with low miles! But at the end of the day it Out of nowhere blew a head gasket and overheated. I’m guessing it was probably the issue all along but I can’t say for sure. Couldn’t get the engine to crank so it wasn’t worth rebuilding and couldn’t find a rebuilt to purchase, only used. Didn’t want to go through it again so we junked it for a measly $150.

The same thing happened to me. I replaced the catalytic converter, fuel injectors, and other parts, certain that I had solved the P0420 code. The code would always eventually come back a few weeks later. Which was strange and annoying because the engine ran perfectly. In desperation i gave up, and installed 2 Dorman foulers (i think 1-42002 and 1-42009) between the downstream O2 sensor and the exhaust pipe. The code never came back. And I am still driving the car today.

Deano