# It is my mechanic!!!



## Dario (Apr 28, 2008)

A few months ago my cars engine check light turned on.  I brought my car to a mechanic and was told my catalyctic converter needs replacing so I had it done (with one year warranty).

A few months after, my engine check light turned on again so I brought it in.  They did some tests and I was told that my O2 sensors are working fine and looks like my catalyctic converter is not working properly so I asked them to replace it under warranty.  I was told that in that case, they will just re-set the light for now and replace it no questions asked next time it turns on again.

2 weeks later, it turned on again so I brought it back in.  I was told that my car needs a tune-up so I had that done.

A week later, light is on again.  This time I was told my O2 sensor needs replacing.  In disgust I told them that I will take a 2nd opinion and do not repair my car.

My car is old and it has 260,000 miles on it.  Never had problems until now and I know it is due but same symptoms (engine check light) for different problems happening on a few months span???

Is it my car or is it my mechanic?


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## Ron in Drums PA (Apr 28, 2008)

> _Originally posted by Dario_
> 
> Is it my car or is it my mechanic?



Yes


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## wjskip (Apr 28, 2008)

Dario
Get a code reader from harbor freight.  The cost is about $39 you will be able to read the codes and know what the answer is befor some crook tries to hoodwink you.  If you know what is really causing the light you can get better service.


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## sptfr43 (Apr 28, 2008)

sounds like your mechanic is making guesses as to what the problem might be.


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## JimB (Apr 28, 2008)

You may want to take it to the dealership. Although it will probably be more expensive than your mechanic they will probably get it right.


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## Dario (Apr 28, 2008)

> _Originally posted by JimB_
> 
> You may want to take it to the dealership. Although it will probably be more expensive than your mechanic they will probably get it right.



That is where I am bringing it next. Thanks.


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## Dario (Apr 28, 2008)

> _Originally posted by wjskip_
> 
> Dario
> Get a code reader from harbor freight.  The cost is about $39 you will be able to read the codes and know what the answer is befor some crook tries to hoodwink you.  If you know what is really causing the light you can get better service.



Is it universal?  I mean, can I use same code reader for any car?


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## splinter99 (Apr 28, 2008)

Dario
It should work on any car 1996 or newer..I have one and really like it..As they said, Its good to know what the problem is before you take it to a garage..
I recommend the sku: 94169 Code reader from HFT..It comes with a cd rom of the trouble codes or you can go to OBD.com


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## Dario (Apr 28, 2008)

Thanks Harold.

BTW, I just drove my car (1997 Toyota Camry) 670 miles last Thursday...and it still averaged 34.12 miles per gallon (mostly highway driving) [^]


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## livertrans (Apr 28, 2008)

Try changing the gas cap. 9 times out of ten this is the problem. If the cap isnt tight or leaks air  the system isnt sealed and the light will go on.


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## Dario (Apr 28, 2008)

Thanks Tony.  I will try that first since it seems to be the cheapest


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## cowchaser (Apr 28, 2008)

My vehicle did this three times. Ended up being the egr. Had it replaced twice. You could unhook the battery to reset it and after about 1000 miles it would come back on. After it came on for the 3rd time I just had it bypassed. Never had a problem again. cost was about 85 dollars with the part being around 30 bucks.


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## alamocdc (Apr 28, 2008)

Dario, if it turns out to be anything the other mechanic worked on, make sure you file a complaint with the Texas Attorney General's Consumer Protection Office. They will help you get your money back. Businesses don't want that kind of heat.


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## rdunn12 (Apr 28, 2008)

First off,tune ups DO NOT fix check engine lights 99 percent of the time unless you have a bad spark plug causing a cylinder misfire.Second ask the for the specific codes and a printout showing the code causing the CEL.The code for a catalytic converter is different from the code for an oxygen sensor.Any good and honest repair shop will show you the printouts showing two different codes.It is possible to have more than one problem and only one code.I see it everyday.Anytime I do a catalyst repair I always recommend the O2 sensors be replaced at the same time.Why?For this very reason.So when you come back in 2 months with an O2 sensor code I can say well I told you so.And no,a gas cap will not fix a code for an oxygen sensor.If it were the gas cap you'd be getting a code for evap system small or gross leak.EGR system does not set codes for O2 sensors either.There are a different set of codes that pertain to EGR systems.You can have those two codes in conjunction with each other but are never related.Hope this helps.


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## MobilMan (Apr 28, 2008)

Normally when a 'check engine' light comes on--leave it.  A lot of times after a few hundred miles it will go out.  If it comes on & flashes, try getting home if close, other wise slow down or pull it over. You've got a problem.  Most honest dealers/garages will tell you the same thing.  I've had the light stay on on by 99 Ford Pu for at least 3000 miles & then go off & stay off .  In 187,000 miles it's done this 4-5 times but I don't worry about it--it's not flashing.  I had a customer come in one evening & asked to bottow a short handled screwdriver.  He went to his PU, put the driver on the light/lense & smacked it with his hand.  "Now I don't have to look at the damn thing."  I couldn't help but grin.


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## Randy_ (Apr 28, 2008)

Dario:  Unless you do a lot of mechanicing work yourself, buying a code reader may be unnecessary.  Lots of auto parts stores have readers in their stores and will read your code for free in hopes of being able to sell you some parts.


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## Russianwolf (Apr 28, 2008)

What Randy Said. Stop by Autozone, Advanced Auto, Pep Boys, etc. and have the codes read, then you'll have an idea of what's going on.

Take the codes and find a forum that is dedicated to the make or model of the car and give the codes to them, they' tell you definitively whats going on.

That's what I did when our saturn started pitching a fit.


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## Gary Max (Apr 28, 2008)

The check engine light has been on in our van for 3 years.
A small piece of black tape is covering it up so I don't have to look at it---I am hopeing the blub will burn out some day.


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## Jarheaded (Apr 28, 2008)

I had the light keep going on in one of my trucks. My mechanic (and long time friend)did everything he could to take care of it, finally we decided that since it wasn't effecting anything with the truck(over 300000 miles) we pulled the bulb and said the heck with it. I wouldn't do that with one of my newer trucks, but if it isn't giving you a problem, and it just keeps costing more and more, why not. I would also look for a new mechanic if I were you, this one sounds a little fishy, don't let him tell you that he will need to change the air in your tires next.[}]


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## tipusnr (Apr 28, 2008)

I'm driving a 1995 Ranger with the check engine light on right now.  I saw the light come on but nothing has changed in the gauges, sound, power, or gas mileage so I'm just leaving it alone until something else changes.


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## mdburn_em (Apr 28, 2008)

Man, what you can't learn on a pen-turning forum.

Seriously, the light came on my Silverado just when it went over 100k.  I am going to take it into a dealer, but I'm saving up first.  I think it has to do with some of the smog control stuff.  (had a local mechanic tell me something like that.)  It is down about 2.5 mpg.


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## toolcrazy (Apr 29, 2008)

Some of the better locksmiths have the tools to check engine codes and the ability to shut off the light. Most of us are having to buy the diagnostic adapters in order to program the new electronic keys. I know ours will do it.


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## Dario (Apr 29, 2008)

> _Originally posted by mdburn_em_
> 
> I am going to take it into a dealer, but I'm saving up first....It is down about 2.5 mpg.



2.5 mpg? WHOA!!! [:0]

I hope you are not driving it much...else you better get it repaired soon especially at the price of gasoline nowadays (you sure ain't saving any).


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## Ron in Drums PA (Apr 29, 2008)

FWIW

We deliver in a Dodge mini van, the check engine light came on around 60,000, the odometer is around 145,000 and the light is still on. 

This happen to our last delivery van, IIRC, I think the light was on for over 140,000 miles.

In both cases, I never worried about it. I think the light is preset by the automakers to help generate revenue.


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## Jarheaded (Apr 29, 2008)

Dario,
 I spoke with my mechanic last night and he said something that makes sense to me. The light is preprogrammed to come on at a certain point so you remember to get a tune-up and just to get the drivetrain serviced. Any mechanic should be able to reset the computer and that should take care of it. If it continues to come on again, then you may have a faulty sending unit somewhere that is giving you a false signal. He basically said that if you don't notice a difference in your milage or in how the car is running, you may be able to spend thousands looking for a problem that doesn't exist. A reading while your light is on should tell you exactly what the problem is and whether you should ignore it or take care of it. Either way, good luck with it.
 Mark, yours sounds like your O2 sensor is shot, a nice simple fix, but can't be sure from here.


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## sbell111 (Apr 29, 2008)

Depending on your make of car, you may be able to easily check the codes yourself.  On my Jeep, all you have to do is turn the key from 'off' to 'on' four times and the codes show up on teh odometer.  Many mopar products work exactly the same way.  There are a few places online to decypher the codes.

On my Allante, I can press a specific button combination and the codes will show on the DIC.

I suspect tht most cars will give you the codes without needing a special tool.  On online seach will likely turn up the method for your car.


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## sbell111 (Apr 29, 2008)

BTW, I wouldn't simply ignore the warning light.  After all, it might be an easy fix that prevents expensive future repairs (or worsening gas mileage).


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## alamocdc (Apr 29, 2008)

Dario, you might need this JIC. If you need it, use it. You won't be sorry. I had to use them with a mechanic and a body shop once.


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## Mudder (Apr 29, 2008)

> _Originally posted by Jarheaded_
> 
> Dario,
> I spoke with my mechanic last night and he said something that makes sense to me. The light is preprogrammed to come on at a certain point so you remember to get a tune-up and just to get the drivetrain serviced. Any mechanic should be able to reset the computer and that should take care of it. If it continues to come on again, then you may have a faulty sending unit somewhere that is giving you a false signal. He basically said that if you don't notice a difference in your milage or in how the car is running, you may be able to spend thousands looking for a problem that doesn't exist. A reading while your light is on should tell you exactly what the problem is and whether you should ignore it or take care of it. Either way, good luck with it.
> Mark, yours sounds like your O2 sensor is shot, a nice simple fix, but can't be sure from here.



That was a trick that got Chrysler sued. I was the manager of a tune up shop in the mid 90's and all Chrysler's had the check engine light come on at exactly 60k . The dealership would then sell a $400.00 plus service to the unsuspecting person. At the time, the place I worked for forbid us to just "turn off" the light unless we did a thorough diagnostic and made sure there was nothing wrong with the vehicle. That ran about $50.00 at the time.


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## Dario (Apr 29, 2008)

I do know about it turning on at pre-determined mileage for maintenance purposes but it was reset 3 times; when the catalyctic converter was replaced, when they tuned it up and again when I brought it in for warranty work.  It shouldn't turn on again until the next 60,000 mile schedule or something is wrong.

As posted earlier, my car still get 34+ mpg on highway driving (and driving within the speed limit ).  I think I will let it go for now.  I just don't want to be stranded somewhere later because I ignored it.  It can get really dangerous and potentially costly too if that happens.  Another concern is if something else come up and the light is already on...then I might never know about it until it is too late.

Thanks guys!


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## Jarheaded (Apr 29, 2008)

Dario, you need to find a good reliable mechanic that knows the type of car you are driving, not all carsa re the same.

Mudder, My mechanic did work for a Dodge dealership for a short time, that may be where he got that info from. Don't understand it, but he still drives a Dodge pickup.


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## Nolan (Apr 29, 2008)

Dario,
I wasnt going to type this out as I am a slow typer and I cant do this it ten words or less but here goes.
1st I used to be ASE certified and actually built some engines for a school to use on test stand for kicking codes on purpose so the students could diagons them.
So the fastest run down on computer and codes............
the system has alot of sensors, acuators and the likes and they all feed info to the ECM in the form of volts, ohms, amps. the ECM knows that each particular whatever it is looking at is supose to run between say 10-50 whatevers, well as soon as "its" measurement falls out of that range it lights a code, intermitent or steady depending on programming features and also where the measurement stays. So here is the problem as some have eluded to. You bring your car in and it has two codes O2 and cat (useing your examples) well could be either one so shop goes with the cheapest or one history has proven to happen the most with that car type, and you know the rest. BUT your car still isint fixed right well here is where this all leads to. If your car kicks a code for o2 "SYSTEM" that doest mean the o2 is bad it means the o2 "SYSTEM" went out of specs. Could be as simple as a loose ground wire which would affect the "SYSTEM" reading. So long story short find a good quality mecanic who knows the make and model well, unfortunatly most of the time that means the dealer unless you just happen upon a really good mechanic. Also not to say that all dealerships are up to snuff. When I had my shop there was a make and model care that had a problem with the temp sensor (which was a wet bulb type) that would alow antifreeze up the wire into the computer and cause all sorts of problems, well the dealer doesnt just tell everyone that and ALOT of shops didnt know about it so you can guess the waisted money. Sorry so long and your right if you care about the car and want to keep it leaving the ligh isnt the best option unless you get a code reader and check your car for new codes every so often


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## Rifleman1776 (Apr 29, 2008)

Disagree with MobilMan and Randy. A check engine light _*MAY*_ mean something serious needs repair. It is a warning. Many times, the repair needed is something minor. But it is not worth taking the chance. Get a code reader. They are invaluable, _*especially*_ for the non-mechanical type. A code reader is good protection from both idiot and dishonest mechanics. With a code reader, you can know before going to a repair garage where the problem is and (usually) avoid being ripped off. And, even for the non-mechanical, if it is the gas cap, you can replace that yourself. Dario, with an older car, you can expect those lights to be coming on often. Sometimes they are set to come on at predetermined mileages, sometimes they are the sign of things getting old. Invest in a code reader.


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## Dario (Apr 29, 2008)

Just got back from HF with a new code reader w/ code manual and CD.   Will read the manual a bit and use it this afternoon.

Nolan, I can actually understand your explanation and thanks for spending the time typing to educate me/us.

Thanks!


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## Dario (Apr 29, 2008)

Tested my new code reader and it returned a P0420 (Catalyst Efficiency Below Threshold (Bank 1))

I called the mechanic and the owner whom I am dealing with is out sick.  Talked to the head mechanic and he claims the P0420 code is for faulty O2 sensor.  I asked him what was the code when they replaced my catalyctic converter and he mumbled same code...but that they replaced my catalyctic converter twice already (a lie) so it must be the O2 sensor.

I can't wait to talk to the owner tomorrow.  This code reader could have paid for itself already .


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## Dario (Apr 29, 2008)

> _Originally posted by alamocdc_
> 
> Dario, you might need this JIC. If you need it, use it. You won't be sorry. I had to use them with a mechanic and a body shop once.



I just might have use for this Billy.

thanks!


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## Scott (Apr 29, 2008)

Dario,

I have a 97 Honda Accord.  The check engine light came on, and I took it to the dealership mechanic.  They hooked it up to the computer, it read the code, they looked up the code in the book, and they said I needed a new transmission.

I then took the car to the mechanic I trust, and he first ran the same diagnostic and got the same code.  He told me that code sometime indicates a problem with the computer chip controlling the transmission.  He checked the transmission over carefully, and then told me he thought the transmission was OK, and just needed a new chip.  I told him to go ahead, he replaced the chip, and the car has run fine ever since.

I will not soon be returning to that dealership!  As a matter of fact, it puts me off of buying Hondas because if it is Honda's policy to replace what could just be repaired, I'm not sure I want to deal with them.  I have been looking at getting a Toyota Prius, but because of the specialized hybrid technology I'll probably only be able to get it worked on at the dealership, and now that worries me!  I don't want to have to replace the engine because I get a bug in the air filter!!!

Sorry about the long, sordid tale.  I wouldn't have said anything, but earlier somebody suggested you take it to the dealer!  Good Luck!

Scott.


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## Nolan (Apr 29, 2008)

> _Originally posted by Scott_
> 
> Dario,
> 
> ...



Scott one bad dealership doesnt indicate a bad car company, sorry but in my post I also put that not all dealerships are up to snuff.


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## Randy_ (Apr 29, 2008)

> _Originally posted by Rifleman1776_
> 
> Disagree with MobilMan and Randy. A check engine light _*MAY*_ mean something serious needs repair......Invest in a code reader.



Frank must be having a senior moment??  Near as I can tell, there are only two Randys in this this discussion and neither one of us came anywhere close to suggesting that the light should be ignored.  

I did suggest the possibility that it might make more economic sense to use the free card reader at an auto parts store rather than spending anywhere from $40 to $200 to purchase one if it was only going to be used infrequently.  Hard to see how one could disagree with that thinking?  Maybe Frank doesn't have a card to his public library??


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## GBusardo (Apr 29, 2008)

Hi Dairo,   I feel bad for you, seems like you are really getting screwed. I am far from an expert mechanic, but I do know that bad catalyctic converter is not easy to diagnose. I wish you luck and if you do feel you got screwed, go after him as others suggested. Let us know if you make any progress.


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## sbell111 (Apr 30, 2008)

> _Originally posted by n4631x_Scott one bad dealership doesnt indicate a bad car company, sorry but in my post I also put that not all dealerships are up to snuff.


I definitely agree.  We've had to swear off a number of dealerships before we found some that we feel comfortable allowing them to work on our cars.


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## Dario (Apr 30, 2008)

I brought my car in today and they did a warranty work.  I am in and out in less than 45 minutes.  Hope they used the right product and did a good job this time.

I believe having the code reader helped me a lot and will probably continue to for some time in the future.  Being "empowered" and having the PEACE OF MIND knowing your mechanic is not taking advantage of you is also a huge bonus.

Thanks for all the input!!!


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