So you pay a ton of money to go to a track weekend and travel half a day to get there. You go out on your first session, get comfortable with the track, you find the driving line and braking points and you even hit a few tight apexes. You get out of the car after the session and you are all smiles as you start checking the tire pressure. You tell your buddy about how great the car felt and how you're going to go out and refine the line, get more consistent and add more speed on your next session. Even the weather is co-operating and it's shaping up to be a great weekend. Well, don't let the ridiculously annoying "Check Engine" light spoil it!
We covered the Check Engine light in this write-up and you probably know by now that all cars sold in the US after 1996 are required to have a diagnostic system to track emissions-related problems. This system is called OBDII (On Board Diagnostics, second generation) and it contains a set of monitored parameters with corresponding fault codes. Regardless of the vehicle you drive, you have probably seen the “Check Engine” or “Service Engine Soon” light displayed on your dashboard at least once after a fault code was triggered.
You cannot know what the problem is without a code reader because there are literally hundreds of possible reasons for it. Sometimes the light is alerting you to the real need for repair, but most often, it is merely indicating a simple type of problem (low coolant level, loose gas cap or oil cap, etc.). Track driving puts a lot of stress on the car and I have seen too many dumb reasons for the Check Engine light to come up over the course of a track weekend. If it decides that the problem is serious enough, the engine management system may force the car into "limp mode", which limits acceleration and revs. Most often, the light just needs to be reset for you to continue driving safely. Since it may take a few cold restarts for the light to reset itself, you should not risk a driving weekend without a code reader that can help you diagnose the problem and reset the light. (The other alternative is to limp around the paddock and curse your bad luck for the rest of the weekend.)
Like most electronics, OBDII code readers have come down in price significantly and you can pick one up really cheap. I like the AutoLink AL309 OBDII because of its ease of use and reasonably good screen that fits multiple lines so you don't have to scroll when the fault code description comes up. This tool plugs into the OBDII port (typically found under the dashboard of most cars) and it works with all domestic and import cars manufactured after 1996. The AutoLink is very light (less than a pound) and it fits easily in the glove box.
You may leave the tool plugged in while doing a running test to monitor parameters live for better diagnosis if needed. It also comes with a readiness monitoring, which allows you to determine when the car is ready to pass inspection after repairs. As an added benefit, AutoLink's manufacturer Autel provides free updates from their website so the tool's library of definitions can always be up to date. The only drawbacks are the short 2-foot cord and the lack of a back button, so you always have to cycle forward on the menu.
Oh, and don't waste your money on code readers that offer "answers" on how to fix the problem behind the code in your car. That's what Google is for!
Top 10 Things to Bring to the Track:
8. Code Reader
9. Big Tarp