Has anyone purchased an OBD code reader for their car? I know there are a host of corded ones at the car parts places. Also, I saw there are bluetooth models that interface with your cell phone with an app. Since my cars are getting to "a certain age" and they like to let me know that the "Check Engine" light is capable of staying illuminated, I was wondering it is worth buying one? I hate running to the parts stores. I do understand that the OTC units do not take the place of the bzillion dollar units the extortionists have.

Any and all ideas are appreciated.

I have had one for several years. All of my vehicles are over 100k miles, and I do all my own service for the most part.

I highly recommend one if you work on your own vehicles. If you do, make sure that you get one that allows you to clear the codes once you've fixed the problem.

There are lots of different levels of readers, from very basic to very advanced. I would buy according to your level of expertise. No use having tons of functions if you don't know how to use them.

As you mentioned, pretty much any parts store will read codes for you if you don't want to buy a reader. My reader is an Innova, although I don't remember which model. I think it ran me around $100. You will save a lot more than that by not taking it to a mechanic.

Greg

I carry one in each car because I want to know more about why the yellow light is on. Then I can decide if it's serious or not.

For someone who can do some of the work on the car it's a basic diagnostic tool. But the tool doesn't necessarily tell you what to change. It is only giving you strong hints about what's wrong. If your car systems vocabulary isn't strong enough to recognize what system it's referring to then it wouldn't be useful.

I think mine are Equus brand - slightly over $100 at the time.

(I've also made friends at work reading coworker's codes and sometimes clearing them. Can be better than putting a $5 bill on their desk when a favor is needed in the future :-)

I find black electricians tape works well. Just slap it over the offending service engine soon light.

In general, I agree except that it won't pass New York's inspection if the light has been on "recently"; whatever the heck that means.

I have a bluetooth one for use with my phone, never needed to read a code but the engine monitor works well.

the extortionists... Sir, you offend me!

Does your car have any kind of digital display on the dash? Some cars allow codes to be read in car without a code reader. Had an 01 Chevy that with the proper combination of button presses would allow me to read and clear codes.

Cars essentially test their own emissions nowadays with a bunch of sensors. If one of these sensors sees something abnormal, it will throw a code/check engine light in the computer. Clearing this code turns off the light, but the computer still sees a fault until it can reset itself by completing whatever driving cycle is required to reset that particular sensor's reading.

The necessary driving cycle depends on the manufacturer and sensor you're trying to reset. For example, one of the parameters for my mustang is to accelerate from 0-45 at least 5 times. You can either do this on purpose or just drive normally and eventually you'll do it anyway.

That's why you'll still fail a state emissions test if you just shut the light off and go. Their reader wont see a clean emissions reading. You have to drive the car for a while after you clear a code to truly reset everything.

To simplify- what the state emissions test is looking for is that the car has completed all the necessary self-tests, has passed them all and set the code for that. If the trouble codes have been cleared, that will show up as having not completed all the self-tests.

Another use for the code reader is to verify the car has passed all the self-tests needed before going to the emissions testing station (if you have one).

There can also be "pending" codes. For example, if you leave the gas cap off and lose it, you won't get the yellow light until the 3rd trip (in my 2001). But if you were to read codes before seeing the light there would be a 'pending' code indicating something could be wrong.

The cycles vs miles thing is the most frustrating. When I was trying to get my car through inspection this year, the guys doing the repairs (two weeks of a lot of guessing going on, guessing which parts to change, resulting in time being wracked up, equaling money out of my pocket on guessing). A heard a lot of "put some miles on it". After almost two hundred miles it still didn't show clear. Left the car at the guessing fix-it guys again. They drove it another bunch of miles and it finally showed clear. Not totally impressed. I long for the day of viable electric cars (300+ mile range; 15-minute recharge) or nuclear powered ones. UGH!

I have no idea if my car has a "Secret Squirrel" way of pressing buttons and turning switches to check for codes. My dash has analog gauges with the standard warning lights.

Lucky! I've got IIRC 15-20 minutes before it shows up.

When I was looking into a yellow light on the wife's car I got into this. She'd been driving it for many trips and a long time but the self-test still hadn't completed. It hadn't recorded an error - it just hadn't completed the tests.

The problem was her driving profile just didn't include the acceleration and speeds necessary for the self-tests. She rarely gets up to 45 mph and drives stoplight to stoplight with few periods of sustained speed. I drove it to my work and back one day (100 mi round trip) and they'd all completed.

One of my main frustrations is that no matter which "experts" that I have to pay loads of money to don't take the time to tell you what kind of "put some miles on it" I need to do. Why do I have to get the info from the Internet?

This is one of the generalized reasons I work so hard to do my own work as much as I possibly can. If I can't do the work I can at least study on the problem so that I can get a sense for whether the expert is going down the right path or just pulling my leg. (refined my BS detection skill in the Navy :-)

Sometimes the experts don't know jack themselves and will make things up.
Sometimes what they know is wrong.
Sometimes the experts will break something else and not tell you.
Sometimes the experts get tired of explaining because some of their customers won't understand, won't believe them, won't listen anyway.

Sometimes the expert is dishonest and just wants your money. (like my local dealership who wanted to rebuild my rear differential and change a front ujoint when I TOLD THEM it was the front diff making noise, that I got lots of metal out of it at the last lube change, and the VIN was only a few hundred different from my other one which self-destructed at nearly the same mileage, and the diff model has a reputation for eating bearings. A pox on them! I went to another shop for the diagnosis and rebuild and have been treated fairly by them since. But I always check their work. Heck, I recheck my OWN work too.)