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P0171, P0420, P0441 OBD codes + excessive oil burning on Toyota Corolla 2002!

I just bought a used Toyota Corolla 2002 CE with 120K miles two months ago. the car seemed fine and drives fine too. After a while I found out that the seller had removed the “check engine” light, so I read the error code by a instrument and I got these errors. 171,420,441. And I noticed that the engine burn a quarter oil every 200 miles on long drives!
I checked the VSV valve and connected hoses but no problem there.
Since the car has just 120K miles, I’m not sure that the piston rings are worn out!
I’m wondering what could cause all of these errors? Do you have any idea?
I think it might be just a simple problem.

I really appreciate if you can guide me.


I can’t really help you, but I’m afraid this is not likely to be a simple or cheap problem. It seems that someone tried to cover up a serious problem here. I will point out that if your engine is burning that much oil then it’s killing your catalytic converter (if it’s not dead already), which is not a cheap part.

Since you asked for guidance, I’ll point out that it’s commonly recommended to get a pre-purchase inspection by a mechanic before buying a used car for reasons just like you’re discovering now, so keep that in mind for your next car purchase.

The search feature has gone haywire but have you posted this problem before?

You are incorrect in thinking that an engine cannot have a piston ring problem because it only has 120k miles on it. Many engines with only 20-30k miles on them end up with ring problems due to overheating, oil sludging, and so on.

The first step should be to run both a dry and wet compression test. My gut feeling is that the results of this test (done properly) will reveal why the original owner dumped the car.

without researching what the codes are. i cant answer that part but as to the oil burning. thats alot of oil. i would start with a comp test. maybe bad rings, head gasket, valve guides, valves who knows. check the compression. and do you have any oil floating on the top of the antifreeze, also check rear main, and cam seal. or if you have access go down to your local do it yourself carwash and power wash your engine top to bottom that way it is clean that way you can see if the oil is just leaking somewhere or is being burned.

Is the Check Engine Light out? I would clear the codes and recheck. Also, I would have a compression test done like the previous smart posters said. Here are your codes and what they “could” mean. Possible fixes are included at

A code P0171 may mean that one or more of the following has happened:

The MAF (Mass Air Flow) Sensor is dirty or faulty
Note: The use of “oiled” air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak downstream of the MAF sensor
Possible cracked vacuum or PCV line/connection
Faulty or stuck open PCV valve
Failed or faulty oxygen sensor (bank 1, sensor 1)
Sticking/plugged or failed fuel injector
Low fuel pressure (possible plugged/dirty fuel filter!)
Exhaust leak between engine and first oxygen sensor

A code P0420 may mean that one or more of the following has happened:

Leaded fuel was used where unleaded was called for
A damaged or failed oxygen sensor (HO2S)
Downstream oxygen sensor (HO2S) wiring damaged or connected improperly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Leaking fuel injector or high fuel pressure
Cylinder misfire
Oil contamination

A code P0441 could mean one or more of the following has happened:

Bad vacuum switch
Broken or damaged EVAP line or canister
Open in PCM purge command circuit
Open or short in Voltage feed circuit to Purge Solenoid
Faulty purge solenoid
Restriction in EVAP solenoid, line or canister
Corrosion or resistance in purge connector

A bit more digging showed this complaint was posted previously and JMHO, but spending one minute or one dime on this car is an exercise in futility considering the oil consumption.

Someone knew this car was damaged goods before they sold it.

Thank you all for your responses.
I talked to a mechanic and it turn out that a lot of Corolla 2002 have had this problem because of the piston ring failure. He proposed using a more viscous oil like 15w-40 and adding lucas additive instead of fixing the engine, since it is expensive.
I will do that, hopefully it helps the engine much more.
BTW I’m not gonna sell it to another one. simply because I’m not like the Chinese guy who sold it to me.

Thanks though

Wait. He physically removed the check engine light?

In many states, that would constitute a crime, to sell the car with a known problem like that that you took steps to cover up. You might wish to do some legal research, especially since your problems revolve around emissions components, which tends to really tick off the government.

Have you considered a rebuilt engine?

I think you would have a hard time legally proving the previous owner knew about the missing light bulb.
He’d probably claim he had no idea anybody did that.
And any mechanic that would do such a thing wouldn’t put it down in writing anywhere.

Before you switch, have your mechanic remove the valve cover and check the oil drain back passages to make sure they are clear and not backing oil up in to the valve guides.

Yeah you are right the seller denied to accept it and said he is dealer and didn’t know. I think we just con not trust to local dealers like these Asian dealer :frowning: (But i believe he knew it )
PS Keith: do you mean the head engine or just the plastic cover of the engine? I opened the plastic cover there is just a bit oil on top of the engine (nothing serious) , but if you meant the head engine, I think it is gonna be expensive to open the engine and simply doesn’t worth it

Hold on a minute, here . . .

The seller . . . “said he is dealer”

You need to go after this guy.
It sounds like he might be trying to sell the car “off the record”

I believe a dealer is responsible for getting all cars that he sells successfully smogged.

The last 2 times I bought used cars from dealers, they paid to get them smogged.

You may want to find out the laws in your state.

I never met the guy, but he sounds like he’s cut-rate.

I agree wiht db4690 that you need to pursue this a bit further; possibly with some state agencies. What state is this in?

A private seller may get away with claiming ignorance of a disabled CEL but I would think that a licensed dealer could end up in some serious trouble over it.

The gray area might be if the seller is a curbstoner.

I believe the guy is a licensed dealer who handled this particular transaction as an off the books “private party sale”

Did you buy the car at the used car lot, or at some other location?

Regardless, you need to make inquiries and possibly go after this guy.

You got taken for a ride, and he should be held accountable.

There is a plastic cover that just covers the valve cover and the ignition coils. It is held by two cap nuts and two plastic retainers, although the plastic retainers are easily broken and usually not replaced. Under that is the valve cover, which is made of aluminum. It does cost more to remove, there are screws all around the edge and the valve cover gasket usually has to be replaced.

Under that is the head and that is way more expensive to take off. I am only talking about the valve cover. If you have a little oil on top of the valve cover, then the cover gasket needs to be replaced anyway. While the valve cover is off, your mechanic can check the valve clearance for you as well as the oil drain passages.

Now about that dealer, he cannot claim ignorance if your state requires a clear smog check before sale. Just because the CEL is off, that does not constitute a check. A code reader has to be hooked up and ALL ready lights have to be on. When a CEL is turned off and all the codes erased, all the ready lights are turned off. It usually takes a couple of drive cycles to get them all back on, only if there are no problems.

If he is a dealer and he is selling the car at his property as a private sale, that can be against the law in almost every state. A dealer or salesman can sell a car as a private sale, but only if it is their personal car. And there is a limit to that. In my state, if they sell more than 5 cars per year from their yard as private sales, then they have to have a separate business license apart from the dealership or they pay a huge fine if caught. The car’s title also has to be in their name prior to the sale.

Sometimes a salesman will see or make a particularly good deal on a trade and immediately buy the trade from the dealer, then take it home and resell it as a private sale. That is legal to do up to 5 times in a year and not all dealers will allow their salesmen to do this. If that is what happened here, the dealer where the trade occurred is still responsible for a clear smog check if required by the state.

thank you all for your guides,
I bought the car in Louisiana. Unfortunately the seller is not a registered dealer. he sold it as a private owner but I know couple of other guys who bought other cars from him. I guess he buys them from others and sells them again. In this case, He said it’s his sister’s car. It was my mistake that I trusted this Chinese guy.
In this case I think there is really nothing that I can do about it.

Thanks Though.

In CT people that flip cars like that are referred to as “curbstoners”, they fix the car along the curb, put a for sale sign on it and move to the next one.
In many states there’s a limit on how many cars you can sell a year before you have to get a dealer’s business license. You may want to check that out for Louisiana and report him, if he’s skating the boundaries of the law. It could help a next potential victim.

was the bulb “missing” or burned out ?

@BigMarc, the bulb was missing. You can’t get any more shady than that.