The Light Show
If it starts to look like a Christmas tree, you could have problems
Sometimes these lights are called “dummy lights” this name comes from the idea that when the light comes on it is almost as if it is saying, “you’ve got a problem dummy, pull over now.” Knowing each MIL (malfunction indicator lamp) that applies to your vehicle really is a must.
Check Engine Light
This light really doesn’t have much to do with the engine itself and has more to do with the engine control systems and the emissions control systems. Sometimes the light might say “service engine soon” or sometimes it might just be an outline of an engine and not have any words around the light at all. Getting rid of words is something that has become more common recently in vehicle controls and instrumentation because it means that the light can be understood regardless of the language of the driver.
When the Check Engine MIL illuminates it means that a failure in the engine controls, or the emissions controls, has occurred that will cause an increase in the emissions from the vehicle. This is bad for obvious reasons, but even if you don’t really care about the emissions from your vehicle, it also usually means that the vehicle is less efficient and you may also notice a loss of power or reduced fuel economy.
If the light illuminates and blinks off and on rapidly, pull your car over and shut it off as soon as you can get to a safe place. The blinking light is meant to instill a greater sense of urgency to get the driver to take the appropriate action. The blinking light also indicates what is referred to as a type A misfire. This is when at least one of the cylinders of the engine stops firing altogether. This is something that can destroy the catalytic converter. The “cat,” as it is commonly called, is an emissions control device located in the exhaust system. When the cat is destroyed it may cost over $1000 just to fix it, let alone the thing that caused the misfire which ruined the cat. This is why the blinking check engine light should never be ignored.
When the check engine light comes on it means something is broken and must be fixed. Some people say that the light on the car just comes on sometimes and shuts itself off later and that this is normal and no big deal. Well it may be normal and the driver might think that it’s no big deal but it still means that something is broken.
The brake warning light can take on many different forms. Sometimes the word “brake” is used all by itself and sometimes there will be some kind of symbol used with brake, or sometimes it’s just some kind of symbol. The brake warning light will usually indicate any one of three and sometimes four different things. The different possibilities will ultimately depend on the make and model of the vehicle in question.
When the parking brake is applied the brake light will come on and stay on until the parking brake is released. This is easy to understand and usually no big deal to figure out, but some people might forget and they will actually drive their vehicle several miles before they realize what is going on.
|The brake light could like anyone of these or all of them together.|
The second thing that the brake light comes on for is low brake fluid level in the master cylinder. This is really easy to check. Simply remove the cap on the reservoir look inside. If the reservoir is translucent, just look at the level through the plastic sides. High and low levels are indicated on the side of the reservoir. If the fluid is low then don’t just add fluid and call it good. Many times when the fluid level falls to a low level it is an indication of worn out brake linings. As the linings in the disc brakes wear, the fluid flows into a larger and larger space behind the caliper piston. This will cause the level in the reservoir to go down. When the pads are replaced and the calipers reset, the fluid is pushed back into the reservoir.
The third thing that causes the brake light to come on is a pressure imbalance in the brake hydraulic system. Usually if the light comes on for this reason, the brake pedal will sink much lower and it will take longer for the vehicle to stop. All cars actually use two separate hydraulic systems to apply the brakes. One system applies the brakes on two wheels, and the other system applies the brakes on the other two wheels. If there is a leak in one of the systems, the pressure in the other system will activate a switch that will cause the light to come on. To repair this kind of failure a professional may be needed and it is obviously not safe to drive the vehicle.
The last thing that will cause the brake light to come on only applies to some cars, usually European cars. This last thing is worn out brake pads. The brake pads on most BMW, Mercedes, and Volkswagen vehicles have a sensor in them. This sensor is tripped when the pads wear thin and it will cause the light to come on. Sometimes the pad wear light may be different from the regular brake warning light.
The battery light is sometimes called the charging system indicator. Either way, the light itself is usually shaped like a battery with a plus and a minus symbol on it. This light will come on when the voltage in the battery or charging system is too low. Many vehicles with a voltmeter in the cluster will also still have a battery light. When the key is turned to the on position but the engine is not started, this light comes on because it is sensing battery voltage only which, without the engine running, will always be lower then what the light and its control systems like to see. When the engine is started the alternator begins to turn and do its job. This will cause the voltage in the battery and charging system to go to about 14 volts if all is functioning correctly. This voltage will cause the battery light to turn off.
|Oil pressure light|
|Oil level light|
Some vehicles have a “Low Oil” light but this is something totally different. If the low oil light comes on it means that you need to add some oil, but you are not really going to hurt anything by driving to a place where it is safe to pull over and have a look. Most cars don’t have a low oil light so don’t assume that yours does. This is the kind of light that you will never see unless your oil level is actually low.
|See this light, check your tire pressure|
Because this is a computer controlled system like everything else on the car, it is capable of monitoring its own systems and alerting the driver if a problem is found. Once again the computer stores a trouble code that indicates what might be going on with the system. Other systems such as traction control and anti-skid control are very much related to the ABS system. These two systems might have their own MILs that may illuminate together with the ABS light if there is a failure that affects the operation of any or all of these systems. If any of these lights are on it might also mean that the corresponding system will not work, or might not work very well. Most of the time, the brake warning indicator comes on with the ABS light.
Maintenance Required Light
Sometimes this will be indicated with words, sometimes it will be indicated with a small wrench symbol. This is a light that comes on to indicate an interval of mileage or time, and indicates that some kind of vehicle service is required. This light can usually be reset without any special tool, but the procedure might not be listed in the owner’s manual. Some vehicles have a maintenance light that says “Service Vehicle Soon,” this should not be confused with the Service Engine Soon light that was mentioned above.
Many other lights can be found on many different types of vehicles. If you are not sure what lights your vehicle has or what those lights mean, check your owner’s manual. The last thing you want on a road trip is an unknown light coming on. You won’t know what it means and you won’t know whether you can continue on your way, or stay put until you get it fixed. No matter what, never forget that lights mean things. Anytime you see one there is a reason that it came on.