DESPERATELY Need Advice Fixing 09 Aveo5!!!!

My 09 Aveo5 is making me go crazy! I foolishly bought the thing with a misfire in the engine. I read online a coil pack would fix it and followed through with the buy. It ran a little rough when I first got it and I plugged in a code tester and got a bunch of codes P0172, P0137, P2270 and found some advice online and bought some parts accordingly. It appeared to be a misfire which damaged the cat. So, so far I have replaced.

- Ignition Coil
- Spark Plugs
- Mass Air Flow Sensor
- Upstream 02 sensor
- Downstream 02 sensor
- Exhaust Manifold / Catalytic Converter

I have a bunch of new shiny parts in the engine bay but the thing drives worse then when it had the original broken coil pack in it. It hesitates and jerks and won't go up hill past 20km/hr. I've literally ran out of things to replace according to the code reader. All of the previous codes including the misfire I have got have gone away except P2270 which is referring to the downstream o2 sensor (post cat). And I've replaced the cat and the sensor!!! The only things I can think of are E-VAP leak or fuel issue which is saying the fuel mixture is wrong to the downstream o2 sensor and jerking the car around attempting to compensate. I am going to do a smoke test and fuel pressure test to see if I can narrow it down, which I should have done in the first place. Or could it be as simple as one of my 02 plugs/harness is fried?

I am going insane and broke trying to fix this thing haha! Can anyone give some advice on this pain in the butt? It would be much appreciated!!!!

What spark plugs did you use? ONLY run NGK coppers.





The only time I have seen a P2270 code was when someone used a "universal" o2 sensor that was not the right band width.

You have replaced a lot of parts, if you still have the same symptoms, and the codes are gone. It is probably something that goes unchecked. Which is fuel and compression. I am not sure what you are looking for with the smoke test, a vacuum leak would "go away" as rpms climb, not act as a miss so much.

Another issue is you replaced the "trifecta" MAF, Coil and o2, but al your codes that you listed originally are o2 codes.
If the primary o2 is bad, it will run like ****. If you put a cheap aftermarket wrong band width o2 in, it will still run like ****. Throwing those other parts in probably didn't fix anything, but the MAF is another one of those parts were aftermarket isn't necessarily right.

Thanks for the reply and taking the time to give advice!!!!

I had a few more codes but didn't write them down those were just the few I managed to write down. One of the original codes was misfire in cylinder 2 which prompted me to change the coil pack and plugs. It drove great for about 30mins. Now like I said it won't go past 2 grand. The p2270 code came up along with all the others before I replaced the 02 sensors. Both p2270 & p0137 kept popping up together but now only p2270 is showing up, I don't know if that means anything.

-First I changed the spark plugs and I used BOSCH platinum plugs and used the owners manual specs for the electrode distance. I went into a auto store here in Canada and just plugged in the cars info to a Ipad they have in the isle and it told me I could use a bunch of different plugs but I chose platinum because I thought the have a longer life. I did not choose copper. None of the codes changed and I didn't notice a difference in driving.

-Then I changed the coil, the misfire code went away and you could physically feel the engine was shaking less and was more even. I went for a 30min drive and it drove awesome had power and acceleration but then by the time I got home it was jerking and bogging down and wouldn't go past 2grand
- Blue Streak (Hygrade Motor) Ignition Coil
Epicor Cover-to-Cover

-Then I bought a OE NGK o2 sensor (upstream) but was still getting a MAF code and didn't notice a improvement since the coil change.
- OE NGK o2 sensor (upstream)
Epicor Cover-to-Cover

-Then I cleaned my old Mass Air Flow sensor, but didn't see any code go away. So I went out and bought a new one. I can't find the exact one I was given when I ordered it in but I'll find the box and let you know. When I put the new one in the MAF code went away at first but did return after a few more tests.

-Then I bit the bullet and went to a professional mechanic for a diagnosis and he told me my cat was so old it started to deteriorate and clog the pipe, it feels like I have a potato in my tail pipe when I drive so that made sense to me. Nice mechanic but the part would be $1300 which was out of the question. I cracked mine off and gave a clean over night but still that did nothing. I found one for around $400 with a 2 year warranty online and bought and installed it, everything fit like a glove but for that price I'd be lying if I wasn't worried. At this point it was still throwing p0137 and p2270
- Catalytic Converter / Manifold
https://mufflerexpress.ca/products/c...2009-2011-obd2

-Then I went out and bought the other O2 sensor (downstream) and put that in. And now I am only getting p2270
-OE NGK o2 sensor (Downstream)
Epicor Cover-to-Cover

I am at a total dead end so that's why I'm going break out the smoke machine, but that's a long shot for sure. Thanks for the advice! I am trying to get a rental fuel pressure test kit but that's proving to be harder then I thought because people like to break them. I also bought a multimeter and I am going to test the harnesses because of the p2270 code. If the fuel injectors or pump is broken or lagging would that trip a code? I know you said they go unchecked?

Platinum plugs are pretty well-known here to cause problems with the Aveo. Not everyone experiences misfires with platinum plugs, but it seems that for the ones that do, the issue apparently can go away with regular copper plugs. I use iridium with no issues, but copper seem to be the "known good" plug for this car.

Also, anything other than the OEM O2 sensors (AC Delco) seems to cause a code for a lot of people, as mentioned above. A few luck out with generic or "OE" style but it seems random.

First thing I would suggest though is to swap out those spark plugs ASAP. You may be pleasantly surprised.

Since you have numerous codes, you probably have more than one problem present.

If the downstream oxygen sensor is involved, you might find this thread helpful:

https://www.aveoforum.com/forum/f108...33/#post207545

I ordered in AC DELCO sensors and NGK copper plugs. Nothing came up in the electrical test and smoke test and I still can't manage to find a fuel and pressure test rental kit that isn't broken, I am still searching though. I am going to follow your guys's advice. The more I research the more AC delco comes up so it's probably that. I made the dumb mistake of thinking "OE" is the same as "OEM". Thank you guys I'll post if it ends up fixing the problem when the parts come in.

So I bought and installed NGK copper plugs, AC delco up and downstream sensors and it still won't go past 2000rpm. And now it won't idle once it's warmed up for about 5mins, it didn't do that before, don't know if that is better or worse. And now when I scan the car its given me more codes now I pasted them below with the meanings I could find online, but again I've replaced MAF and both O2 sensors and it is still telling me they are bad. Does that mean the circuit is bad? I found a running theme of bad circuits when I was researching so is it wise to assume I have a bad electrical problem? The wire sheathing in the car is in a pretty cracked state so maybe its shorting all over? And theres still fuel and compression to test? This car is driving me mental!!!



P0443 Evap Emission Control System Purge Control Valve Circuit Malfunction
-Faulty Evaporative Emission (EVAP) Purge Solenoid Control.
-Evaporative Emission (EVAP) Purge Solenoid Control harness is open or shorted.
-Evaporative Emission (EVAP) Purge Solenoid Control circuit poor electrical connection.


P0030 HO2S Heater Control Circuit Bank 1 Sensor 1
-Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit.
-Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse.
-Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit open shorted to ground.
-Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit poor electrical connection.
-Faulty Powertrain Control Module (PCM).


P0036 HO2S Heater Control Circuit Bank 1 Sensor 2
-Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2.
-Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 fuse.
-Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 harness is open or shorted.
-Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit poor electrical connection.
-Faulty Powertrain Control Module (PCM).


P0102 Mass or Volume Air Flow Circuit Low Input
-Faulty mass air flow sensor.
-Intake air leaks.
-Dirty mass air flow sensor.
-Dirty mass air filter.
-Mass air flow sensor harness is open or shorted.
-Mass air flow sensor circuit poor electrical connection.


P0597 Thermostat Heater Control Circuit Open
-Failed Engine Cooling Thermostat.
-Engine Cooling Thermostat harness is open or shorted.
-Engine Cooling Thermostat circuit poor electrical connection.


P0098 Intake Air Temperature Sensor 2 Circuit High
-Faulty Intake Air Temperature sensor.
-Intake Air Temperature sensor harness is open or shorted.
-Intake Air Temperature sensor circuit poor electrical connection.


P2270 Oxygen Sensor Signal Stuck Lean Bank 1 Sensor 2
-Faulty Rear Heated Oxygen Sensor Bank 1.
-Rear Heated Oxygen Sensor Bank 1 harness is open or shorted.
-Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
-Exhaust gas leaks

check this thread. looks like you have electric problem.

https://www.aveoforum.com/forum/f108...nnector-21745/
https://www.aveoforum.com/forum/f82/...sor-1-a-20985/