How Much Do You Know About Cars?
How much do you know about cars?
It’s not just trivia, either. Knowing some things about cars – or at least, some car lingo – can help you come across as more car-savvy, even if you’re not a gearhead. And that can help you avoid getting ripped off by a bad apple car salesman or service advisor. The bad ones are looking for marks – and if you appear to know something about cars, probably, they’ll save the shuck and jive for the next guy.
Anyhow, back to the lingo:
*OBD II –
This acronym refers to the Onboard Diagnostics II computer (and interface) that all cars have had for about 20 years now (since the mid-late 1990s). The OBD system governs the operation of the engine and related systems. If a problem is detected, a trouble code is stored in memory – accessible via a scanning tool that plugs in to a universal port (it’s the same in all cars, regardless of make/model) that’s usually located near the hood release catch in the driver’s side footwell area.
If a trouble code is thrown, the yellow “check engine” light in the main gauge cluster will come on and stay on, indicating the need for service.
Normally, this light only illuminates momentarily when you first start the engine, then goes off. If it comes on and stays on, it is not an emergency – you can continue to drive – but you should take the car in sooner rather than later to avoid a small issue becoming a big one.
Be aware: In states that have mandatory emissions testing, an illuminated “check engine” light will result in the car failing the test. Which usually means you can’t renew the vehicle’s registration – or get it, if you just bought the car used.
If you’re looking at a used car prospect, note whether the “check engine” light comes on at start-up and then goes off right away. If it stays on, there could be an expensive problem with the emissions controls, including the catalytic converter. You want that resolved before money changes hands.
Be sure to drive the car around for at least 15 minutes or so, incidentally. Because it’s possible someone with a scan tool (see below) cleared the trouble code(s) from memory. This will temporarily cause the “check engine” light to go out. But if the underlying problem that triggered the code wasn’t fixed, the light will come on again.
And if it does after money changes hands, it’ll be your problem.
* “02” sensors –
If the “check engine” light comes on, a fairly common reason for that is a bad O2 – oroxygen – sensor. Take a look at your car’s exhaust system. You’ll see pipes and mufflers and things that kind of look like mufflers (these are the catalytic converters, which are mounted upstream from the mufflers). Somewhere forward (closer to the engine) you will also see a stubby little protrusion screwed into the piping, with an electrical pigtail on the back end of it. This is an 02 sensor – and your car may haveseveral of them. Usually, there is at least one ahead of the catalytic converter – and one right after the catalytic converter. If your car has a V6 or V8 engine, you may have as many as four 02 sensors.
The 02 sensors sample the exhaust stream as it flows past, noting its chemical composition. This, in turn tells the OBD II computer whether the engine is running within spec and not too rich (excess gas in the air-fuel mix) and so on, which is critical for both emissions control and top performance/efficiency. If an O2 sensors goes bad, the computer is no longer receiving the data it needs – or receiving bad data – and a trouble code will get thrown and the “check engine” light will come on.
The upside is that with OBD – and a scan tool – it is possible for a technician to knowwhether the car has a bad 02 sensor rather than guess. The trouble code he pulls from the OBD II diagnostic port will tell him yes – or no.
You can do this yourself, too. Easily and fairly inexpensively. A hand-held OBD II scan tool costs about $120 (the better ones give you the code as well as tell you what the code means) and anyone who can turn an ignition key has the necessary skills to plug it into the OBD II port and pull the codes.
Even if you don’t want to do the actual repair work yourself, having the scan tool – and knowing what codes have been thrown can be very helpful when discussing your problem with a shop. You’ll know, for example, that they’re bullshitting you if they claim the OBD computer is telling them you’ve got “x” issue when you checked yourself and found the problem is actually “y”.
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