Check Engine Light

Wesley

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Apr 12, 2006
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Omaha
Did you make sure the gas cap was on tight. Seems like a loose cap sets more sensors off than anything.
Code must still be reset. At least that was the case for a 2007 Nitro and a 2003 GM Pickup that needed a reset as light stayed on until turned off. Both had gas cap problems.
 
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papaw

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Aug 16, 2011
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If I had to live a life thanking everybody was out to screw me, I would be miserable. Your life shouldn't be so busy that you can't do your research on car repair shops, house A/C, plumbers, and so forth. Don't wait until you have a problem. You know that you will eventually have a problem and you need to know who to use.
If I thought I needed to know all a plumber knows to keep from getting screwed, I picked the wrong plumber.

Papaw
 

papaw

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New cars the codes do not have to be reset. If the problem is fixed it will go out by it self after a drive cycle. It is about 25 miles of combined stop and go and on the hwy.
I am certainly not wealthy, but $50-$100 is not a lot compared to a couple hours away from my business. You would be money ahead throwing your toy scanner away and spending time researching a reputable business.
Papaw
 

HOTDON

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Mar 24, 2006
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Go to a parts store, get the code, look it up online. There are forums for every car, and people who have seen the same code.There's a good chance you'll find out what it is, how much it should cost, and how to fix it. If you're handy you can fix it, if not, you know what needs to be done. If it's too new to have major problems, pull your gas cap off and put it back on. They can be very touchy.
 

clonefan98

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Apr 12, 2006
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Not sure that all vehicles do this, but my Grand Caravan will display the codes on the odomoter if you cycle the key between "Off" and "Acc" 3 times fast, then just google the code(s) you get.
 

papaw

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I bet you use a plumber to do your agronomy?


ISUAgronomist



Quote:Spoken like a true, blowhard Texan.

You do realize that is the first step any shop is going to take. Why bother paying someone to do something you can do yourself? Most situations can be fixed in your own garae. If not, the few times that it did, that "toy" paid for itself and then you can pay a mechanic for more technical problems.

I'm an Okie by the way. Did they teach you agronomy and auto repair at ISU. I bet you are a true success and loved by your fellow man.
Did you learn spelling at what university?
Papaw
 

Cyclonesrule91

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Apr 10, 2006
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Waukee
A check engine light or emission light is a Federally mandated emission light for all vehicles sold in the USA. Some and very few vehicles have lights for maintenance reminders. It is separate from the engine light. Remember if you get an 02 sensor code, if it is an 02 sensor remember that most cars have 4 now. Do you replace them all at $125 ea or pay a reputable shop to replace the one that it needs.
Papaw

Or if it's like 75% of repair shops out there, they will tell you all 4 $125 O2 sensors are bad when only one might be faulty, charge you $250 / piece to change them out and $110/hr to do it plus another 2 hours extra. Then they will see rust on the edge of your brake rotors and try and screw you out of $700 to replace $39 pair of brake pads.

Take it to Autozone and they can help you figure it out and save you a pot load of money. If it's an O2 sensor, weather changes can trip them off and the light will go out by itself within a few days.
 

papaw

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I don't know how many crooked shops there are in your area, but it sounds like you need to find the good 25%
I feel sorry for you folks, because if 75% of one trade is crooked, so are the people in you state. Honest people wouldn't stand for it and run them off.
Has not a person on this forum found an honest repair shop?
I guess I live in fairy land. I am an Okie, but other than the university of texas I have found it to be a pleasant place to live. Sure wouldn't want to live in Iowa with all the crooks.
Papaw
 

Cyclonesrule91

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Apr 10, 2006
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If you aren't handy at mechanical work or don't have a friend that can help you, still go to Autozone and have them help you figure out what it is for free. Then when you take it to potential rip off repair joint and speak about what you think could be wrong by what you found out at Autozone, you might be less likely to get screwed over when you come across as a clueless consumer ripe for the picking. I could tell you all sorts of horror stories about people getting raped by repair shops. There are good ones out there but I trust noone.
 

Scott34

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Mar 16, 2007
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I would have it tested at your local parts store that does it for free. I personally wouldnt buy one of those cheap $50 scanners from WalMart, sometimes they dont tell you everything. You need a professional grade one and those arent cheap. Then when you find out what is wrong, you can look it up yourself or take it to your mechanic.
 

ruxCYtable

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There are forums for every car, and people who have seen the same code.There's a good chance you'll find out what it is, how much it should cost, and how to fix it.
This is good advice and absolutely true. I recently had a code on our Caravan, got on the owner forums, got advice on how to fix it and even links to how-to videos.
 

packattack425

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Went to Ammaco and they gave me a code. They reset the light and said if it comes back on to bring it back in and they will do a free diagnostic. I have to get the check engine light off so I can pass emissions in Wisconsin so I can renew my plates. If it is a expensive repair, I might claim residence in Iowa and register my car here so I don't have to pass emissions. Not looking to put any more money into my car.

P0421 was the code. I drive a '02 Mitsubishi Lancer
 

Stewo

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Oct 29, 2008
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Went to Ammaco and they gave me a code. They reset the light and said if it comes back on to bring it back in and they will do a free diagnostic. I have to get the check engine light off so I can pass emissions in Wisconsin so I can renew my plates. If it is a expensive repair, I might claim residence in Iowa and register my car here so I don't have to pass emissions. Not looking to put any more money into my car.

P0421 was the code. I drive a '02 Mitsubishi Lancer

You're welcome.

P0421 - Club4G Forum : Mitsubishi Eclipse 4G Forums - 2006-2012 Eclipse Authority
 

Entropy

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Oct 27, 2008
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Went to Ammaco and they gave me a code. They reset the light and said if it comes back on to bring it back in and they will do a free diagnostic. I have to get the check engine light off so I can pass emissions in Wisconsin so I can renew my plates. If it is a expensive repair, I might claim residence in Iowa and register my car here so I don't have to pass emissions. Not looking to put any more money into my car.

P0421 was the code. I drive a '02 Mitsubishi Lancer
Did a quick check on some forums and it appears this is a known issue with Lancers and a defective catalytic converter? Has it ever been replaced? It sounds like there was at one point a recall on them.

It doesn't sound like it's a critical code (i.e. your vehicle will still run).
 

Stewo

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Oct 29, 2008
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I would also add that you can install "dummy" sensors that will give a false readings and that will turn your CEL off. I had to do just that after I put headers on my GTO.
 

Cyclonestate78

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May 23, 2008
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If you aren't handy at mechanical work or don't have a friend that can help you, still go to Autozone and have them help you figure out what it is for free. Then when you take it to potential rip off repair joint and speak about what you think could be wrong by what you found out at Autozone, you might be less likely to get screwed over when you come across as a clueless consumer ripe for the picking. I could tell you all sorts of horror stories about people getting raped by repair shops. There are good ones out there but I trust noone.

This is the only way to be anymore. Money is money and in an economy like this even some of the more reputable places will be more then willing to take an unsuspecting customer for a ride.
 

papaw

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This is a note from the blowhard Texan as Cyclonerules91 calls me. I have a 02 Lancer as you do. Mine has the same problem. code PO421 is for a warmup cat. converter. They had a recall that was for 8 yrs or 100,000 miles. You can disconnect the battery cable and the light will go out temporarily. If you get it replaced be sure and have the computer reflashed or reprogrammed or it will melt your new cat.
Remember, this is coming from an Okie that lives in Texas and is now a blow hard Texan.

Papaw
 

packattack425

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This is a note from the blowhard Texan as Cyclonerules91 calls me. I have a 02 Lancer as you do. Mine has the same problem. code PO421 is for a warmup cat. converter. They had a recall that was for 8 yrs or 100,000 miles. You can disconnect the battery cable and the light will go out temporarily. If you get it replaced be sure and have the computer reflashed or reprogrammed or it will melt your new cat.Remember, this is coming from an Okie that lives in Texas and is now a blow hard Texan.Papaw

My car has over 100,000 miles so it looks like the recall isn't an option.
 

Cycsk

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Is there anywhere in Ames I can go to get a check engine light diagnostic for free? I know most place charges for this. I thought Autozone did it for free but there isn't one in Ames. I kind of want to know what is wrong with my car so I can either fix it myself or avoid having some auto place to tell me they want to fix a million different things with it.


I have 6 cars for which I get almost all my service at Midas on Lincoln Way near Duff (I take care of the cars for everyone in my family). And I see lots of ISU students there. These guys have always been very honest and fair. A few months ago, they even told me it was time to get rid of a car rather than put any more money into it (and didn't charge me anything for the diagnosis).
 

isukendall

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Nov 30, 2006
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In my opinion it's rarely "free." Many places that offer to check the codes for free will use the information to try to sell you something. Some places might even lie to customers about what the code means and push them into an unneeded repair.

I have a code scanner that gives me the code, tells me what it means and then gives me three choices which basically boil down to: 1. Forget it and keep driving; 2. Get it checked out at your convenience; or 3. Stop driving immediately.

I can't tell you how many times I've used it and how many unneeded trips to have codes checked out I've avoided in just seconds in my own garage. I'm not a corporate CEO or anything but my time is pretty valuable to me and in my opinion it was $50 well spent. My wife drives a Dodge so it gets a workout.

This. Cheap OBDII scanners will be well worth having, especially if you have a car with a lot of miles. Between my wife's car and mine, I probably have used it dozens of times. Most of the time it's some crap oxygen sensor code. Sometimes you have codes that pop up every winter. Worth the money to be able to erase it yourself and move on.

Also, my wife has a VW Jetta that runs in "limp mode" if the check engine light is on, for any reason. Another case where it's worth it to be able to shut it off if it's a crap code.