Friday, March 18, 2011

That Pesky Check Engine Light

Over the past 16 years, on board diagnostics have become universal in our vehicles. The most common system, by far, is the OBD2, or "on board diagnostics version 2." Because we generally have learned to ignore all the new gadgets under the hood ("just some air pollution device"), most of us never know what that "computer" the mechanic talks about really is.

Just in the past couple of years, "readers" for this system have become common and inexpensive. (Before last year, I never saw one less than $100) The absolutely lowest price readers may just read out a code, but for not much more, you can get one that tells what the code means and is able to reset it, thus turning of that pesky check
engine light.

These things are great but, as any shade tree mechanic will tell you, they don't replace doing the basics. I am often astonished at the simple things people don't do to take care of their vehicles today. For the average person, owning the average car or truck, they should still pop the hood about once a week and check all the fluids. This means oil, transmission fluid, power steering, coolant, and brakes. One note on these, especially on the brakes, most vehicles are designed so you can shine a flashlight through the resevoir to check the level. Don't open it if you can help it. And don't add brake fluid, if it is low, it is time for maintenance.

And check the tires too. I do this visually each week (on my work truck I do this daily, as it is driven in a hostile environment), and with a gauge once or more a month. Low tires steal your money.

Now, on the subject of the check engine light, and the OBD2 system that turns it on, manufactures will always be looking for ways to bilk money out of their customers. So in times past, they included "secret" codes that only the dealers knew what they were. Today, the sensors and codes continue to become more complex, with new codes likely to be unknown to the available readers. A possible follow on to the OBD2 system integrates it, wirelessly, into computer networks owned by either the government or the car manufacture. This is already underway in some makes and models and is likely to allow a great deal of mischief on the parts of both. I don't have enough information on these developments at this time, but plan to do more research in the near future.

On the other hand, there are some codes that have a simple fix. One code indicates a leak in the fuel system, and that one may be no more than "you didn't tighten the fuel cap enough," or left the engine running while putting fuel in the vehicle. These are big no-no's, as today's fuel systems are sealed, and only vented through a charcoal canister (known as an evap system). Others may require fixing, but not right away. I had a problem with the torque converter clutch being "stuck off." OK, it is a problem, but only costs me a mile per gallon in the near term. I have been erasing this code about once a week for a couple of months now. I plan to get it fixed, but don't really have a specific idea of when.

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