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weston631

@optonline.net

Check Engine Light - Knows very little about cars

I know very little about cars and can use some (detailed) guidance, please.

I have a 2003 Toyota Corolla with 155,000 miles, mostly highway miles. It has been regularly maintained at the Toyota dealership for all these years.

Last Thursday, I got gas at a Gulf gas station, and the gas attendant "overfilled" the gas tank after it clicked by about 55 cents.

The very next night, driving home from work, for the first time I ever had the car, the "Check Engine Light" came on and remained solid.

The next morning I brought the car to an independent tire/mechanic shop and they read the codes with their scanner. He didn't provide me with the codes, but said while he couldn't pinpoint the exact issue of the car with the codes, it was most likely the Oxygen sensor(s), Catalytic Converter or something emission related.

He reset the "Check Engine Light" and said next time it goes back on to come in and he'll check the codes again.

My car passed New York State Inspection a few weeks ago. The car seems like it is it running and driving fine, as far as I can tell.

1. Is it possible the "Check Engine Light" came on when there is no real issue?

2. Since he reset the "Check Engine Light", if it's a real issue, when will the "Check Engine Light" come back on? How many miles of driving, starts, etc?

3. If the codes did show something related to the emissions, (Oxygen sensors, Catalytic Converter , etc.), is it perfectly safe to drive for an extended period of time and many miles with the issue? (I rather not put more money into the car, and just buy a new car before next November, since I know it wouldn't pass inspection again.)

4. Is it "likely" that the car could have passed NYS inspection a few weeks ago, in addition to the Toyota dealer's "Multi-Point Inspection", and then developed this issue a few weeks later?

Your detailed response would be so helpful and appreciated. Have a very happy and healthy Holidays!



mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3



At this point, lacking any detailed information about what the actual trouble codes were, I would recommend just driving it as usual, and wait to see if the light comes on again.

Some vehicles are sensitive to being overfilled, but I am not sure on your particular car. If Cho Baka See Profile checks in, we can get more detailed information on that.

To be honest, I'm not impressed with the response your chosen mechanic gave you. He should have been able to pinpoint the code source, and how old each code (if there was more than one) is in the system. The range of potential issues is about as broad as it can be. I would have been happy if he said "fuel system problem" or "catalyst problem" but not all of those...

Anyway, if it runs fine, has no other operational issues and the light stays off, you can dismiss it totally. If it comes back on, please find a different shop to perform proper diagnostics, and if you wish check back here with the results.



PoloDude
Premium,VIP
join:2006-03-29
Northport, NY
kudos:3
reply to weston631

There is no way putting another 55c in the tank set off the CEL. However you should check that the gas cap is on securely.



neonhomer
KK4BFN
Premium
join:2004-01-27
Edgewater, FL

said by PoloDude:

There is no way putting another 55c in the tank set off the CEL. However you should check that the gas cap is on securely.

This is what I was going to say. My mother had a 04 Ranger, and the CEL triggered, and I believe the fault was just a general emissions system code. The gas cap had a bad gasket. New cap and problem went away.

I'm weary of any mechanic that cannot (or will not) tell you what the codes are that come out of the PCM.
--
"F is for Fire that burns down the whole town...
U is for Uranium...... Bombs...
N is for NO SURVIVORS!!!!!" Sheldon Plankton

Keep Calm and Carry On


weston631

@optonline.net
reply to weston631

Thanks a lot for the responses. I appreciate it.

The mechanic I went to that read the codes wasn't my mechanic. I've always used the Toyota dealer since 2003, but because I didn't want to wait all day at the dealer, I just brought it to the local shop and they read the codes for free, and reset the "Check Engine Light". It's now off, but I'm wondering when the CEL will come back on, if there is a real issue?

I tightened the gas cap prior to having the CEL reset, but it seemed like it was tight already. It was night time and hard to see.

If there is a real issue, would the CEL come back on after driving 100 miles, 200 miles, etc? Thank you so much!!



mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

1 recommendation



If the light comes back on, then yes, it needs to be addressed. As I noted, a proper diagnostic needs to be completed that will isolate the nature of the problem.

As far as when it will come back, that is up to the situation at hand; No problems present to cause the light to come on again, then it won't be back on at all, at least for that particular problem. The more significant the issue, the faster it comes on. For example, an engine misfire that is detected will immediately cause the light to come on, and if it is a persistent misfire, the light will actually flash to signify "take care of this NOW!". This is because a persistent misfire condition can cause damage to the catalytic converter, as well as cause excessive tailpipe emissions in the form of raw, unburned fuel.

Other problems that are less critical and non-damaging may take several "detection cycles" to set a trouble code and turn on the light. If the problem is detected over a certain number of start-stop cycles, or for a certain length of time, it will come on. Then there are codes that will be set in the computer but don't cause the light to come on at all. Typically these will be body-control module issues, and some drivetrain scenarios that are out of range. They are detectable only when a technician performs diagnostics, and then they can be addressed if needed.

There's a quick and basic explanation of the Check Engine Light display strategy.


Kearnstd
Space Elf
Premium
join:2002-01-22
Mullica Hill, NJ
kudos:1
reply to weston631

gas caps are fairly cheap so if it turns out to be that than its a minimal issue.

Is it mission critical though is what I wonder. As in if someone never fixed the gas cap would the car be harmed? as in does the gas tank have to be kept at a positive pressure?
--
[65 Arcanist]Filan(High Elf) Zone: Broadband Reports


Bob4
Account deleted

join:2012-07-22
New Jersey
Reviews:
·Optimum Online

said by Kearnstd:

if someone never fixed the gas cap would the car be harmed? as in does the gas tank have to be kept at a positive pressure?

No and No.

In New Jersey, you would fail inspection.


weston631

@optonline.net
reply to Kearnstd

Since the CEL was reset a few days ago, I drove about 200 miles and maybe turned the car on/off 20 to 30 times.

The CEL has not come on again yet. Is that a "good sign" or do I still need to give it more driving cycles and more miles?

Thank you so much!!


Bob4
Account deleted

join:2012-07-22
New Jersey

Sounds like it was just a loose gas cap.

Now you know which mechanic NOT to go to!


Kearnstd
Space Elf
Premium
join:2002-01-22
Mullica Hill, NJ
kudos:1
reply to Bob4

said by Bob4:

said by Kearnstd:

if someone never fixed the gas cap would the car be harmed? as in does the gas tank have to be kept at a positive pressure?

No and No.

In New Jersey, you would fail inspection.

Yea I know they check the gas cap on this goofy adapter thing hooked to an air compressor and a computer. Mine has never failed thankfully.

I wonder how they test those fords that have no gas cap.
--
[65 Arcanist]Filan(High Elf) Zone: Broadband Reports

Bob4
Account deleted

join:2012-07-22
New Jersey

You also fail if the check engine light is on, or if the car's diagnostic port indicates a problem with the gas cap.



weston631

@optonline.net

Update:

The CEL came back on (after about 250 miles and a few days) so I brought it to the Toyota dealership.

They said the code was P0420. (Catalyst System Efficiency Below Threshold)

I just passed inspection a few weeks earlier (before CEL came on) but they said it was just a "coincidence" it happened right after.

Is it safe to drive with this issue for several months? I'm not due for another inspection for several months and before next inspection, I rather buy a new car. I already put a lot of money into the 2003 Corolla.

They quoted me about $1700 for the new catalytic converter and “reflashing the computer”, which is also needed.

While I certainly don’t want to add to the pollution, from a mechanical point, is it perfectly safe to drive for many months and many miles?

Thank you so much!!!



shdesigns
Powered By Infinite Improbabilty Drive
Premium
join:2000-12-01
Stone Mountain, GA
Reviews:
·Atlantic Nexus
reply to weston631

Check an independent shop; $1,700 is a lot for a cat. That's what the 4 cats on my mustang cost to get replaced at the dealer.

I paid about $250 for a generic one on one of my cars at a muffler shop.

It is safe to drive. Sounds like the cat is getting fouled or the catalyst is flaking off.

Is it burning oil? That can plug up a cat.
--
Scott Henion

Embedded Systems Consultant,
SHDesigns home - DIY Welder


spud

join:2007-03-24
Constantine, MI
reply to weston631

Your Toyota Camry use's a heated oxygen sensor with a service life of about 100,000 miles
I'd bet the internal heater circuit in the O2 sensor isn't working right
The sensor can't produce and send the rapidly toggling voltage signal till its above 600 F
So without the heater it only works right some of the time
The OBD II system monitors converter efficiency by comparing the upstream and downstream oxygen sensor signals
O2 sensor is easy enough to check but if you have 155,000 miles on them I'd replace both
as a Regular normal car maintenance item and with a Toyota Corolla clean the mass air flow sensor
also Try a different brand of Gas then go from there it is perfectly safe to drive



mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3
reply to weston631



For sure I would suggest a second estimate, but do NOT settle for a cheap "universal fit" replacement converter. There are high-quality aftermarket converters available, and make sure you specify that or you will have other problems down the road.

It is not going to give you any operational issues in the near future, but it would be best to make the needed repairs as soon as you are able to do so.


Tig

join:2006-06-29
Carrying Place, ON
Reviews:
·voip.ms
·TekSavvy DSL
reply to PoloDude

Actually on a Toyota, it can, but it has nothing to do with the OPs O2 sensor. When you overfill some Toyotas. For example my 2000 Corolla, the charcoal canister can flood and the solenoid that tests the gas cap gets gummed up. Next drive cycle will result in a CEL.


Tig

join:2006-06-29
Carrying Place, ON
Reviews:
·voip.ms
·TekSavvy DSL
reply to spud

said by spud:

Your Toyota Camry use's a heated oxygen sensor with a service life of about 100,000 miles
I'd bet the internal heater circuit in the O2 sensor isn't working right

There's a specific code for that. It's failed on my Corolla. I monitored the sensor operation and noted that the code posted several minutes after the O2 sensor had warmed up and was operating as normally. I'll change it at e test time.
To the OP.
For $20 you can get a Bluetooth OBDII scanner. A free smart phone app will then display the sensor operation so you can see for yourself. Sensor one should toggle high and low constantly, sensor two should not because the cat is burning the residual fuel.
If they both toggle it means the cat is not doing it's job.
As mentioned, cleaning the MAF is a good idea to avoid an ugly lean stumble. Different OBD code(s) for this.
The best thing about owning a Toyota seems to be learning how all these things work (or break).


Snakeoil
Ignore Button. The coward's feature.
Premium
join:2000-08-05
Mentor, OH
kudos:1
reply to weston631

I had a check engine light go on. I have a Dodge so was able to get the code off of the odometer.
Turns out the gas cap had a bad seal.

If you have a pepboys or advanced auto, go to them to get the code.
I find it interesting the repair place didn't "keep" the code and let you know what it was.
--
Is a person a failure for doing nothing? Or is he a failure for trying, and not succeeding at what he is attempting to do? What did you fail at today?.



Snakeoil
Ignore Button. The coward's feature.
Premium
join:2000-08-05
Mentor, OH
kudos:1
reply to weston631

said by weston631 :

Update:

The CEL came back on (after about 250 miles and a few days) so I brought it to the Toyota dealership.

They said the code was P0420. (Catalyst System Efficiency Below Threshold)

I just passed inspection a few weeks earlier (before CEL came on) but they said it was just a "coincidence" it happened right after.

Is it safe to drive with this issue for several months? I'm not due for another inspection for several months and before next inspection, I rather buy a new car. I already put a lot of money into the 2003 Corolla.

They quoted me about $1700 for the new catalytic converter and “reflashing the computer”, which is also needed.

While I certainly don’t want to add to the pollution, from a mechanical point, is it perfectly safe to drive for many months and many miles?

Thank you so much!!!

The one auto repair place I worked at never did exhaust work. They'd go to an after market exhaust place to have the repairs done there.

Hence, I doubt your dealer will do the actual work, but send it to a local muffler shop.
So you may just want to look up exhaust repair places in your local area, or ask one of the techs at the dealer, who they would recommend. You might find the price cheaper after cutting out the middle man.

I stopped going to the dealer after the warranties on my vehicles expired. I go to a family owned chain shop. Their prices are lower then the dealer, and they have always been friendly and helpful.
--
Is a person a failure for doing nothing? Or is he a failure for trying, and not succeeding at what he is attempting to do? What did you fail at today?.


Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
Reviews:
·TekSavvy DSL
·Cogeco Cable
reply to weston631

What mattmag said.

Assuming that the OP's VIN is before the production break, it also appears that the dealer is correct on the ECM replace/reflash. There is a TSB to address a P0420 + P0136 issue. If they also need the converter, I will assume that they have done a test to check the performance of the catalyst.
--
The talented hawk speaks French.



TOPDAWG
Premium
join:2005-04-27
Midland, ON
kudos:3
reply to weston631

maybe I'm wrong but I've had bad gas set off my check engine light before. at least I think that is what it was and could be your issue too.

Shit saw rest of thread ignore me. WTF you can't remove posts on here or something?


rody_44
Premium
join:2004-02-20
Quakertown, PA
Reviews:
·Comcast

2 edits
reply to weston631

I wouldnt be so fast to do anything. I would go to autozone and have it cleared again. If the gas did get in the carbon canister which is common on toyotas it takes some time to go away. I could see the vehicle throw a catylist code with that. Most toyota owners know its a big no no to overfill a toyota.