Check Engine Light

[am_vanquish]

I was cruising along this weekend when I noticed the "Check Engine" light was illuminated on my dashboard. I drive a 1999 Mazda Protege (not in great shape, but it doesn't need repairs every other month either). I know hasn't been on for long. Prior to this weekend, I didn't notice anything out of place with the way it was driving (other than the usual things for a 10-year-old car). It's still running the same as before, but now I'm paranoid & I think every little squeak is something horrible.

I don't want to avoid this too long & make any problems worse. However, I also don't want to pay too much for a simple problem (I read that not tightening your gas cap all the way can even set off the light). All mechanics I've called have told me it will cost $90 to "diagnose" the problem. One place told me they could pull the codes for free, but would also charge $90 to diagnose the problem. Apparently they can only tell me if it's the transmission, o-2 sensor, engine, etc. Past that, it could still be something simple & cheap or something horrible & expensive.

I'm looking for any suggestions/advice that would be helpful. Let me know if there's any more info you need.

[disneysteve]

They sell the sensors that you can plug in yourself and get the codes. They are a little pricey but perhaps you can find a friend or relative who has one. Maybe even get a cheaper one on ebay. I've thought about buying one myself since we have two older cars. Use it twice and it pays for itself.

[irmanator]

If you have an auto zone they can check it for you for free.

[tripods68]

Unless you have all the necessary tools to diagnosed your car, go for it. Otherwise, it is usually better to eat the $60 bucks and have a professional mechanic look at it and tell you what's wrong with your car. If your going to the same repair shop that diagnosed it, ask for a discount on the diagnosis or for total repair jobs. It doesn't hurt to ask especially if you used that same mechanics in the past.

If it a sensor problem, you have to replace it. I know engine lights "bug" me the most. I usually take care of it as soon as it appears.

[plumpossum]

If you have an auto zone they can check it for you for free.

Advance Auto Parts does free diagnostics too.

My husband works in the parts industry and was formerly an auto tech, and we have a diagnostic code reader at home. It's saved us a ton of money because we both drive finnicky cars (2 Volvos, 2 Saabs) and our lights turn on for everything. His has thrown a code on the gas cap before. Mine has triggered a "check engine" light when one of my brake lights was out. Another time was because the cam shaft position sensor was out- the brake light was a quick, inexpensive issue that I wouldn't want to pay a mechanic to fix (or the gas cap ), but the cam shaft sensor was pretty pricey (although easy to install).

[tripods68]

If you have an auto zone they can check it for you for free.

I didn't know this. I should visit there next time.

Thanks.

[am_vanquish]

If you have an auto zone they can check it for you for free.

I just got off the phone with an Auto Zone about 4 miles away. They said they'll check it for free & it'll only take 2 seconds. That's quite a contrast to the Pep Boys store that's 0.5 miles from the house. I called them on Saturday & they said I'd have to leave it overnight & they'd charge me $95.

I'm going to stop by after work today ... now I'm crossing my fingers and hoping it's nothing major! If it sounds like something serious, I'll take it to my regular mechanic, who's probably going to charge me $80 just to look at it.

-Thanks irmanator!!

[red92s]

Code readers have gotten fairly cheap in recent years:
Amazon.com: Autel MaxiScan MS300 CAN OBD-II Code Reader: Automotive

Some diagnostic trouble codes are universal and apply to all vehicles, while others are manufacturer specific. While the code certainly can help in determining what SYSTEM the problem lies in, it does not indicate WHY a particular error is occuring.

For instance, the thermostat on my Protege failed last year, causing the car to overheat and the check engine light to come on. The code indicated that the ECT (engine coolant temperature) sensor had originated the code. So I tried replacing the ECT sensor, and the car still overheated. Then I replaced the thermostat and the problem went away (there is no sensor for the thermostat). The ECT sensor was a SYMPTOM not a CAUSE: it tripped out and turned on the check engine light once the coolant temp got to high.

[nmboone]

When my 03 Civic light comes on it just says something about Maintenance. It usually just means that it's time for it to be looked at for regular maintenance and nothing major. I have it reset on the next oil change. This is obviously not the case for you, but don't worry too much and definetely go to AutoZone. If they aren't busy they are usually really nice about it. However I do think they had a limit for the car year that they can diagnose. At the one my sister visited the years were 2000+.

[kork13]

I have it reset on the next oil change.

A bit of a side note, but how do you get the maintenance lamp reset? For my '07 Civic Si, it goes off for oil changes and anything bigger, and I'd like to start doing at least the oil myself, but have no idea if/how I can get the thing reset. My warranty is about to run out, and the local dealership just tried to up-sell me on a couple maintenance non-issues, so I'm now leery of going there to ask them to do it...

[maat55]

A bit of a side note, but how do you get the maintenance lamp reset? For my '07 Civic Si, it goes off for oil changes and anything bigger, and I'd like to start doing at least the oil myself, but have no idea if/how I can get the thing reset. My warranty is about to run out, and the local dealership just tried to up-sell me on a couple maintenance non-issues, so I'm now leery of going there to ask them to do it...

My daugther has an 06 civic. I have changed her oil the last three times. Your dash button on the left has a sequence where you can reset the oil life. I have to re-learn it everytime so you may want to consult your manual.

Hers uses 5w 20 oil, make sure you know which oil to use. Do not worry about using Honda oil, we use valvoline.

[kork13]

My daugther has an 06 civic. I have changed her oil the last three times. Your dash button on the left has a sequence where you can reset the oil life. I have to re-learn it everytime so you may want to consult your manual.

Hers uses 5w 20 oil, make sure you know which oil to use. Do not worry about using Honda oil, we use valvoline.

Much thanks, I'll look for that then.

[atomicrc11]

Also keep in mind that when the check engine light goes on it just means take it in soon to get it checked out. If the check engine light is flashing, stop driving the car immediately as that means there may be a serious problem that may cause damage to your engine.

[am_vanquish]

UPDATE: I stopped by AutoZone last night & they pulled the code. The OEM Number was P0455 & the technician said it's the fuel cap. The store was busy, so he really just said "fuel cap" and handed me a printout. He didn't have time for any other questions, which I understand. Rhe print-out he gave me listed the following probable causes:
1. Faulty Fuel Cap
2. Canister faulty
3. Purge valve solenoid faulty
4. Damaged/leaking EVAP hose
5. Faulty EVAP leak detection pump.

I tightened the fuel cap this weekend after the light first came on, so I doubt that a loose fuel cap is the problem. However, I did read online somewhere that it can take a few trips to "reset."

I really don't want to start running down this list replace things that aren't actually the source of the problem. However, I also don't want to pay $80-$90 for my mechanic to tell me I need a new fuel cap.

As of right now, I'm thinking about just driving it until this weekend to see if it goes away. From the list above, it doesn't look like I'll do a ton of damage if I wait a little while. But, I'm not very knowledgeable about cars, so ...

[red92s]

Sometime AutoZone can do that. I tried and they told me they could not plug into my car for some reason.

You might have to visit the dealer...

what year is your car?