Before the government forced auto manufacturers to work on reducing air pollution, there was no need for a microprocessor in a car. Now a car might have as many as about 50 microprocessors. Your car’s ECU, for instance, is a 32-bit, 40-MHz processor on average. But it really doesn’t sound like much. I mean, your computer likely has a 500-1,000-MHz processor. But that’s not where the beauty of the ECU technology lies. It comes from the fact that an average ECU requires about 1 MB of memory. Flat out, 1 MB of memory. Your computer? About 2,000 times that (auto.howstuffworks.com). The reason? Code efficiency. Not all codes have the same efficiency, and that becomes even truer when you compile two million codes to run one complex thing.
It’s a closed-loop system, meaning it receives feedback from other units, sensors, and microprocessors and is capable of commanding other units. So not only does it know the coolant temperature at any given time or the amount of oxygen coming out of the exhaust, but it can also change things. It gets input from sensors, interprets the data and then changes the time and frequency of things like the fuel mixture, ignition timing, valves and the like.
So let’s check out things that you can ignore in the short term and some things that you can’t ignore at all.
15 IGNORE: TIRE PRESSURE
The flipped horseshoe with an exclamation point means that at least one of your tires is low on pressure. Now, I’m generally all about being proactive and what have you, but this is one of those things that I think people can let slide by without incurring any major damages to the car.
As long as you didn’t hear a loud blast involving one of the tires of your car, you should be okay, as this light comes on for as simple a thing as a tire with low pressure. A low-pressure tire is not going to destroy your tires, and it’s not an imminent threat.
14 IGNORE: TRACTION CONTROL
Since the 2012 model year, all cars have traction control as standard. The system is easy, as it doesn’t require anything new. It essentially uses the same sensors that are used by the antilock brake system. Both of those were federally mandated for 2012 and higher model years.
The traction-control system light sometimes comes on and goes away. That’s normal.
It comes on when the tires might have experienced an episode of skidding momentarily and then goes away. You don’t have to do anything. And while the traction-control system light may stay on, it becomes a concern, but is not an imminent threat.
13 IGNORE: LOW WINDSHIELD WASHER-FLUID
The sign looks like an open hand-held fan. But the closed box is supposed to represent the windshield, and the dashed line is supposed to represent streams of water.
Unless you happen to be living in a place where it’s wintertime, you can go ahead and ignore this sign.
You don’t need the washer fluid all the time, and when you do, it’s like once in a blue moon. Plus, it’s not like your wipers are not working. You can always just run the dry wipers
12 IGNORE: SERVICE DUE SOON
Ah, the wrench with the words “Service Reminder” or “Service Due Soon.” I have had this one displaying in my car for some weeks now. I’m not lazy, and I have planned out the time to get it fixed, but it’s not an urgent thing.
It’s actually one of the more useful lights to come on the dashboard. The light is there to remind you of the impending oil change (and filter change). Not that it’s a nuisance (at least in my car), but should you want this light to stop displaying all the time, you can go ahead and manually reset it.
11 IGNORE: GLOW PLUG
Diesels have their own magic. They are usually stronger and a little more powerful than the gas-powered vehicles. But a diesel engine also starts differently. In a gas engine, there’s this thing called spark plug that ignites the fuel. Diesels don’t have that. They use pressure to ignite the fuel.
However, in cold weather, this thing called glow plug is used to assist with the temperature aspect. So if a light comes on, it usually means that the glow plug has become weak. While you should get it fixed at some point, it’s not an urgent thing. You can still cruise around the neighborhood.
10 CAN’T IGNORE: POWER STEERING
This sign, a steering wheel with an exclamation point next to it, means that the power steering has gone out. This one is a bit troublesome because of the associated fears. If the sign has come on, but there isn’t any noticeable difference in your steering, you can’t exactly relax.
“What’s the sign there for?” That will be the first thing running in the back of your mind. And that’s a very good question. It could be as simple as something is off with the power steering—but not enough to cause the loss of anything. But you can’t be sure. And you definitely don’t want to lose power steering on a highway.
9 CAN’T IGNORE: OIL PRESSURE
This one is a deeply serious sign. Quite frankly, you don’t want to mess with this sign at all. On some cars, this sign might be in amber to indicate low oil level, but otherwise it’s a red warning lamp that comes on to rightfully scare you a little.
It’s in your best interest to take it to the mechanic as soon as possible.
The problem is, if the oil level is so low that there’s just not any lubrication, your engine will be kind of grinding. And as you may have guessed it, there’s no way of being able to save a welded engine.
8 CAN’T IGNORE: BRAKE WARNING
This one is a bit tricky. One of the most common reasons is that the brakes just need to be replaced. The light won’t tell you which brake it is, just that it’s time for it (or them) to be replaced. While this is not necessarily dangerous, the light could also signify leaking brakes. And that my friends, is quite dangerous, as in severe cases, you might not be able to stop the car due to the malfunctioning brakes. Simply put: take it to the mechanic (yourmechanic.com).
7 CAN’T IGNORE: CHECK ENGINE LIGHT
This is one of the least clear signs that you’ll find in your car. The engine has hundreds of things in it that could possibly go wrong with it, and all you’ll get is this check engine sign, which is basically an outline of an engine.
You’d have no way of knowing whether it’s a minor electrical issue or if it’s a minor mechanical issue, or if it’s a major engine problem.
There’s just no way of knowing what the exact problem is until you take it to the mechanic and have a diagnostic test run. Nonetheless, it’s a good idea to have it checked out lest you incur more damage.
6 CAN’T IGNORE: ABS LIGHT
Much like the normal brake warning, this one should be taken seriously. The anti-lock braking system helps make sure the wheels don’t skid during a violent episode of braking. If one of the wheels starts locking up, a sensor on that wheel sends the message to the ECU, which then limits the braking on that wheel, because as you know, if you start skidding, the worst thing is to continue applying brakes. Doing so just propagates the skidding. So if something is off, you probably want to have it checked out, as you don’t know when you’ll need your brakes with force.
5 CAN’T IGNORE: COOLANT TEMPERATURE LIGHT
This one is also a decently vital one. It essentially means your coolant is overheating and not doing the job of keeping the engine cool.
Sometimes this bad boy pops up in blue, indicating that the coolant temperature is below what’s needed for exceptional performance, but with some time, it goes away.
But if it’s the heart attack-inducing red warning light, then that means the car’s coolant is overheating, and you had better pull over to the side and turn off the car. The longer it’s turned on, the more it will overheat, and the more damage it will accumulate.
4 CAN’T IGNORE: AIRBAG LIGHT
Airbags are among the top things that are very crucial for your survival while driving. I wouldn’t play around with the airbag warning light. There could be anything wrong with the airbags, and I’m sure you wouldn’t think you’re safe with driving such a light on. As careful as you are, the next guy might be in a different state of mind, and there go your car and some of your bones. I’m not sure what the exact numbers are, but I’d imagine the chances of life loss increase exponentially without airbags. There can’t be any room for error with this sign, that’s for sure.
3 CAN’T IGNORE: BATTERY CHARGE
This one is kind of a bad one to have thrown at you. You’re driving to your job and everything is going well. You have clear goals and know what you need to do for the day. And then this light comes on.
This light generally means the battery juice is running low.
Being the good motorist, you turn off all the accessories that might drain the battery even more, meaning no more AC. But the problem is, if you turn off the car somewhere, you can’t be sure if it will ever start back again without resuscitation. So you'd better choose wisely.
2 CAN’T IGNORE: TRANSMISSION TEMPERATURE
This is a pretty tough one too. While the engine might be somewhat familiar to commoners, most people don’t know about the transmission. It’s the thing that’s right next to the engine and changes gears.
While the very first thing you’d want to do is pull the vehicle to the side and turn it off, doing so doesn’t guarantee safety. Yourmechanic.com states that heat is the most common culprit for transmission failure than anything else. Plus, for every 20 degrees of temperature beyond the ideal temperature of 200 degrees, the transmission life is cut by a factor of two.
1 CAN’T IGNORE: SEATBELT LIGHT
If you buckle down and the light goes away, all is good. I’m not talking about that scenario. I’m talking about when you put the seatbelt on, but the light doesn’t go away. And that’s a pretty bad situation to be in. Because you can’t be sure that the seatbelt that you put on is of any value.
What if the corrupted sensor doesn’t send the correct message down the pathway, and the pretensioner system doesn’t work when called upon? That’s a pretty bad situation to be in, and I definitely wouldn’t be comfortable with driving my car like that. Get it checked out.
Sources: hhmobil.com, says.com