How to diagnose (resolve) error codes from engine?

[Chaznsc]

Trying to help my daughter fix her 2005 Toyota Matrix. I have an OBD scanner and Torque app for my android phone. Below are the error codes coming from the system. The three errors are related, but Im not sure how to troubleshoot this or just take it in.

Fault log report generated by Torque for Android
=================================================
Vehicle Manufacturer: Toyota
Vehicle Calibration ID: 30274100
Current Fault Log
------------------
P0441: Evaporative Emission Control System Incorrect Purge Flow
P0455: Evaporative Emission Control System Leak Detected (gross leak)
P0456: Evaporative Emission Control System Leak Detected (very small leak)
Pending Fault Log
------------------
ECU reports no pending faults
Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged
End of report.

 

[Fortress68]

I always check the gas cap when codes like these pop. Make sure it is closed, and then, if so, I buy a new one just to be sure. It sure beats chasing down phantom problems only to find out that was it in the end, and it's cheap. I have seen bad gas caps about 8 times in the last 3-4 years. I would bet on it being because of ethanol in the fuel, but that is really not my concern.

 

[steve308]

Does look like a gas cap issue -replace cap - disconnect battery power for about 30 seconds - hopefully problem solved without trip to dealer --

 

[Chaznsc]

Ok, I wil pick one up. Will somethingfrom autozone work or do I need an OEM part?

 

[steve308]

"Stant" is your best bet - check advance or carquest or federated if one in your area

 

[Chaznsc]

Thanks, will start here. Will resetting the codes be the same as disconnecting the battery?

 

[GTA Matt]

Highly unlikely the gas cap is the problem on one of those. Before you waste any money on one, you need to check the purge solenoid for sealing. It is located right by the air filter. If you can blow through it, it is bad. You need to be sure all lines are hooked up correctly and of course check the gas cap seal. The vent solenoid and vent VSV are located on the evap canister under the car and are the most problematic. You really need the proper scanner and smoke machine to test. The vent solenoid, pressure sensor and VSVs all come together with a new evap canister from Toyota. I replace at least 1 a week. If you decide to go with a new cap, get Toyota only. Parts store caps are ****.

 

[Chaznsc]

Highly unlikely the gas cap is the problem on one of those. Before you waste any money on one, you need to check the purge solenoid for sealing. It is located right by the air filter. If you can blow through it, it is bad. You need to be sure all lines are hooked up correctly and of course check the gas cap seal. The vent solenoid and vent VSV are located on the evap canister under the car and are the most problematic. You really need the proper scanner and smoke machine to test. The vent solenoid, pressure sensor and VSVs all come together with a new evap canister from Toyota. I replace at least 1 a week. If you decide to go with a new cap, get Toyota only. Parts store caps are ****.

Any idea what the parts cost on this assembly you mentioned?

 

[GTA Matt]

Any idea what the parts cost on this assembly you mentioned?

Canister can be $2-300. I wouldn't suggest replacing it without testing. Assumptions are bad when it comes to these things. It may be cheaper to take it to someone that is familiar with toyota evap systems as they are one of the more complex setups.

 

[jethro29]

i find it unlikely that a gas cap is going to solve your issue,but if you do buy a new cap then use o.e. only do not use an aftermarket.this system really needs to be tested with a smoke machine and they other thing you need to know is if this car is a california emmissions car or not,it should say on the label under the hood that tells you the engine size and year.toyota evap systems are a p.i.t.a. and even more so if it's california.i really would just suggest that you take it to a shop to be diagnosed atleast,then you could purchase and install the defective part/ parts.

 

[JakeKohl]

Gas cap. It wasn't a Toyota but I had the same codes (except the purge valve) and a new gas cap solved it. It could be as simple as your daughter leaving the cap off or loose after a recent fill. I would reset the code (use the OBD software to reset codes - no need to disconnect battery) and make sure the existing cap is tight. If the error code comes back, replace the gas cap. The cap is pretty cheap and easy so even if it is something else, you haven't wasted much time or money troubleshooting it.

 

[joe_padavano]

Does look like a gas cap issue -replace cap - disconnect battery power for about 30 seconds - hopefully problem solved without trip to dealer --

Most OBD II computers store error codes in non-volatile memory. Disconnecting the battery is not supposed to erase them. You need a scan tool to do it. On the other hand, most OBD II computers also have the ability to sense that a problem has been fixed and will turn the light off on their own after a predetermined number of start cycles where the problem is no longer seen.

 

[kamesama980]

Highly unlikely the gas cap is the problem on one of those...

I'd say quite likely if someone forgets to get it on all the way, cross threads it, or forgets alltogether. Which is the case more often than mechanical failure IME. Clear the code and see if it comes back.

Most OBD II computers store error codes in non-volatile memory. Disconnecting the battery is not supposed to erase them. You need a scan tool to do it. On the other hand, most OBD II computers also have the ability to sense that a problem has been fixed and will turn the light off on their own after a predetermined number of start cycles where the problem is no longer seen.

Some codes are stored in NV memory, stuff for airbags for example. Engine codes are usually in volatile memory with things like fuel trims. Keep in mind this is an 8 year old car. clearing the code itself depends on the code and mfr

 

[Trey T]

Typically these codes, 9 out of 10 times, I've seen it's not the gas cap. It has to do with the VSV switch.

 

[TwoInch]

make sure she is pumping gas with the car off.

 

[billybudge]

Hi:
Seen this before, many times,
Are you ready.

It relates to,:
An oxygen sensor (or lambda sensor) . faulty or faulty connection,

Located Cat converter.

I would just replace the sensor and see what happens,

cheeers

 

[Chaznsc]

While we debate this one, are these codes "life threatening" to the engine?

 

[GTA Matt]

Hi:
Seen this before, many times,
Are you ready.

It relates to,:
An oxygen sensor (or lambda sensor) . faulty or faulty connection,

Located Cat converter.

I would just replace the sensor and see what happens,

cheeers

I hope you are joking. You are saying the post cat o2 is causing an evap leak code. Think on that one for a while.

While we debate this one, are these codes "life threatening" to the engine?

Not at all. Just indicates a leak or malfunction in the fuel vapor collection system. One thing I would suggest would be to remove and try to blow through the purge valve. If it is stuck open it can pull fuel vapor and fuel into the intake and cause a rich condition that could cause some driveability issues and worst case scenario damage the catalytic converter.

 

[billybudge]

While we debate this one, are these codes "life threatening" to the engine?

Hi Mate:
This is your decision to make, but My own personal feeling would No,

But fault codes are there for a reason,

Check the exhaust manifold for leaks, follow this to the cat converter, on there there is a sensor ,measuring flow of emisions,/ purge etc, see if the wiring is good not broke or burnt through,, and if the sensor has come loose, normally they are in so tight it can be a right muther to get it out,

this is where the problem is,

Good luck with it.

 

[billybudge]

I hope you are joking. You are saying the post cat o2 is causing an evap leak code. Think on that one for a while.



Not at all. Just indicates a leak or malfunction in the fuel vapor collection system. One thing I would suggest would be to remove and try to blow through the purge valve. If it is stuck open it can pull fuel vapor and fuel into the intake and cause a rich condition that could cause some driveability issues and worst case scenario damage the catalytic converter.

?,Not sure what your talking about, Are the fault codes different in the US than the rest of the world, ? or is it the terminolgy of parts ,?

the fault codes read:
P0441: Evaporative Emission Control System Incorrect Purge Flow
P0455: Evaporative Emission Control System Leak Detected (gross leak)
P0456: Evaporative Emission Control System Leak Detected (very small leak)

Ok,
Evaporative = Gas vapor emission:
Emission = Exhaust gas vapor.
Put them together + Evapoartive Emission MEANS EXHAUST FUMES,
then just work out the rest
Leak detected. = ok, the sensor thinks there is a leak, as the misture of carbons is lower than it is programmed to read,
Could be a poor or weak fuel mxture, ( but other problems would be more noticable)
So there come be a leak, would hear or smell it,
So the chances are it is the sensor

Are you guys actually trained vehicle mechanics,

 

[GTA Matt]

?,Not sure what your talking about, Are the fault codes different in the US than the rest of the world, ? or is it the terminolgy of parts ,?

the fault codes read:
P0441: Evaporative Emission Control System Incorrect Purge Flow
P0455: Evaporative Emission Control System Leak Detected (gross leak)
P0456: Evaporative Emission Control System Leak Detected (very small leak)

Ok,
Evaporative = Gas vapor emission:
Emission = Exhaust gas vapor.
Put them together + Evapoartive Emission MEANS EXHAUST FUMES,
then just work out the rest
Leak detected. = ok, the sensor thinks there is a leak, as the misture of carbons is lower than it is programmed to read,
Could be a poor or weak fuel mxture, ( but other problems would be more noticable)
So there come be a leak, would hear or smell it,
So the chances are it is the sensor

Are you guys actually trained vehicle mechanics,

That might very well be the worse information I have ever read on-line. You also owe me a keyboard and a monitor. The monitor because I spit pepsi all over it when I read that and a keyboard because I just beat my head on it. Evaporative emission= on board fuel vapor recovery. I.E., fuel vapors are not allowed to vent to atmosphere. Absolutely nothing to do with the fuel injection system, exhaust, etc.

 

[billybudge]

That might very well be the worse information I have ever read on-line. You also owe me a keyboard and a monitor. The monitor because I spit pepsi all over it when I read that and a keyboard because I just beat my head on it. Evaporative emission= on board fuel vapor recovery. I.E., fuel vapors are not allowed to vent to atmosphere. Absolutely nothing to do with the fuel injection system, exhaust, etc.

Try and stay focused and answer the question, Are you a actually trained vehicle mechanic,
as I am rolling over laughing my nuts off with your replies,

 

[GTA Matt]

Try and stay focused and answer the question, Are you a actually trained vehicle mechanic,
as I am rolling over laughing my nuts off with your replies,

I kinda fix cars for a living....... Have 9 ase's, L1, blah blah blah.

I still think you gotta be pulling somebodies leg to come up with that.

 

[jethro29]

the condition/s which set the codes and turned on the mil ,will not harm your engine or drivetrain in any way whatsoever.honestly my best advice for you is to take it to a competent repair shop that has A= a smoke machine. B= a scanner that does bi-directional testing. C= a trained and competent tech to use those tools to diagnose. one thing for sure i will tell you is that AN O2 SENSOR ,CAT CONVERTER,OR EXHAUST LEAK have NOTHING to do with your issues.as it is with an evap issue,ESPECIALLY TOYOTA,there are so many things that can cause these codes,do not waste your money by throwing parts at it.please let us know how it turns out.

 

[Chaznsc]

Everyone,
Thank you the valuable input (and banter). I'm not a true mechanic, bit of I can safely male a repair, it helps my bottom line. I will kick the tires on this and make a decision of I can. Lucky for me, I do have a mechanic I trust.

I will update on this soon.

Thanks again.

 

[LX-Markham]

I'm with GTA and jethro on this one. You can't just take random synonyms of the words and make a new sentence. Evaporative emissions are totally unrelated to exhaust emissions. Must be a language thing LOL.

 

[Alta_Racer]

My money is on a vent valve, and probably it has killed the canister too. Valve is unable to fully close, or fully open, due to dirt, which gets pulled into the canister. cant close, so you get the large/small leak codes. Stuck nearly closed, or canister plugged, low flow during purge.

OP: this car sees a bunch of gravel/dusty conditions? If so a better filter for the vent or relocating it nay help, if my long distance diag is correct.

 

[Hawk]

I am going to say start with the simple first. My son had his codes pulled and they were the same as your daughters. He went and bought a new gas cap, same problem. I went out and turned the cap till it clicked. It cleared the codes after a few miles. Turned out he thought you just turned it till it stopped and had not properly closed it numerous times. Not saying that it will solve the problem but it makes more sense to check out the small stuff first. By the way we put the original cap back on properly and no more codes. Flame away but I will stick with what works before putting more bucks into a solution that may not be needed.

 

[scarney1988]

Procedure


1.Write down the DTCs and print any freeze frame data associated (although it wont be too helpful in this case)
2.Clear the codes
3.Complete a successful drive cyle (EVAP monitor will set or it wont)

I can scan in my toyota manuals, but I need to now what EVAP system you have.​

4.If EVAP monitor is "PASS" than stop there is no problem.
5.If the monitor is "FAIL" than please come back and note the codes.

TIPS/QUESTIONS
1.Make sure you gas cap is tight before the test drive
2.Do you have a vacuum gauge (preferrably one with a hand pump)?
3.Make sure all Vacuum lines are connected properly under the hood specifically the line that goes to and leaves purge valve on its way to the air box
4.If a customer did not want to pay for diagnosis I would tell them to start with a gas cap and purge valve however there is no garuntee

Diagnosing EVAP is tough without the proper equipment (Techstream, Smoke machine, etc...).
GOODLUCK

 

[gayler]

?,Not sure what your talking about, Are the fault codes different in the US than the rest of the world, ? or is it the terminolgy of parts ,?

the fault codes read:
P0441: Evaporative Emission Control System Incorrect Purge Flow
P0455: Evaporative Emission Control System Leak Detected (gross leak)
P0456: Evaporative Emission Control System Leak Detected (very small leak)

Ok,
Evaporative = Gas vapor emission:
Emission = Exhaust gas vapor.
Put them together + Evapoartive Emission MEANS EXHAUST FUMES,
then just work out the rest
Leak detected. = ok, the sensor thinks there is a leak, as the misture of carbons is lower than it is programmed to read,
Could be a poor or weak fuel mxture, ( but other problems would be more noticable)
So there come be a leak, would hear or smell it,
So the chances are it is the sensor

Are you guys actually trained vehicle mechanics,

http://www.obd-codes.com/p0442

 

[Chaznsc]

UPDATE:
I finally decided to start simple and work my way up the food chain. Changed out the fuel cap and its been a week and NO error codes so far. They had been coming back almost immediately after resetting.

THANK YOU TO ALL WHO HELPED ME DIAGNOSE THIS. THE OTHER IDEAS ARE TUCKED AWAY IN CASE THIS GOES OFF AGAIN.

 

[flht1997]

?,Not sure what your talking about, Are the fault codes different in the US than the rest of the world, ? or is it the terminolgy of parts ,?

the fault codes read:
P0441: Evaporative Emission Control System Incorrect Purge Flow
P0455: Evaporative Emission Control System Leak Detected (gross leak)
P0456: Evaporative Emission Control System Leak Detected (very small leak)

Ok,
Evaporative = Gas vapor emission:
Emission = Exhaust gas vapor.
Put them together + Evapoartive Emission MEANS EXHAUST FUMES,
then just work out the rest
Leak detected. = ok, the sensor thinks there is a leak, as the misture of carbons is lower than it is programmed to read,
Could be a poor or weak fuel mxture, ( but other problems would be more noticable)
So there come be a leak, would hear or smell it,
So the chances are it is the sensor

Are you guys actually trained vehicle mechanics,

that is the funniest thing I have read in a long time. So your saying my muffler sensor says I have an exhaust leak?
Quite a few of us here are technicians, a lot of certified Master Technicians, myself included, many others are manufacturer trained and certified.
Your suggestions are ridiculous and your deductions based on synonyms to words contained in a fault code are truly a foolish way to fix a car.

 

[billybudge]

that is the funniest thing I have read in a long time. So your saying my muffler sensor says I have an exhaust leak?
Quite a few of us here are technicians, a lot of certified Master Technicians, myself included, many others are manufacturer trained and certified.
Your suggestions are ridiculous and your deductions based on synonyms to words contained in a fault code are truly a foolish way to fix a car.

Im really trying to understand you level of knowledge, but where in what I have said, do I mention a leaking exhaust, ?, and since when has a catalytic converter become a muffler,
Im talking CO2 emissions,
We do not have the charcoal canister, etc or sealed vapor fuel systems as in the US, well not yet anyway, not in most motors
This is why I stated that there may be a terminolgy difference,
Generic fault code readers are a base of where to look, but they are generic, however, If you used a fault reader from the main dealer would it give you the same code , diagnoses, and would it be the same across the pond,

I have found this to be very interesting, I would to know more about the charcoal canister,
How many times a year to do test your emissions, I guess its not so much the CO2 level , is it NOx
I am not taking the pzzz, as My fault generic optied for the cat convertor sensor,

 

[flht1997]

The codes that the OP is talking about deal with the Evaporative Emissions and this is dealing with basically the fumes in the gas tank not escaping into the atmosphere. These codes have nothing to do with Nox or CO or any other tailpipe emissions or catalytic converter function. I guess you could argue it is HC coming out but since there isn't a acceptable limit, anything coming out is too much.
Most vehicle that are in an area with emission testing is generally tested once a year. Then it is just a code and readiness test.

 

[sdguy55]

Try and stay focused and answer the question, Are you a actually trained vehicle mechanic,
as I am rolling over laughing my nuts off with your replies,

Look at this guy trying to be English billy badass with poor typing and worse grammar. Welcome to GJ, helps to not be a smartass right off the bat. Mate.