What do the warning lights on the dashboard mean?

Warning lights on the dashboard will tell you if there is a problem under the hood. Simple. Right?

Actually it's not that easy. There are so many warning lights in modern cars that it can be confusing. Let's demystify this.

The warning lights on the instrument panel are part of the on-board diagnostics (OBD). Until 1996, automakers had their own diagnostic systems. The codes and indicators varied by brand and model. In 1996, the industry standardized many Diagnostic Trouble Codes (DTCs). The 1996 standard is called OBD-II.

The impetus for this move in the industry was compliance with vehicle emissions regulations. But it had additional positive effects. First, it has become easier for car owners and service technicians to diagnose engine problems.

When the warning light comes on, it means your vehicle's diagnostic system has detected a problem. It stores the fault code in its memory.

Sometimes the engine will adjust to the problem on its own. For example, if your oxygen sensor detects a problem, it can adjust the air/fuel mixture to fix the problem.

Yellow and red warning lights on the dashboard

It is important for drivers to know the difference between yellow and red.

If the warning light is flashing red, stop in a safe place as soon as possible. It is not safe to drive a vehicle. If you continue driving, it could endanger passengers or expensive engine components.

If the warning light is amber, take your vehicle to a service center as soon as possible.

Check Engine Indicator (CEL)

If the CEL is blinking, the problem is more relevant than if it is constantly on. This could mean several different problems. Many of these problems are related to your emissions system. Let's hope it's something as simple as a loose gas cap.

Easy Solution: Check the Gas Tank Cap

If you do not tighten the gas tank cap tightly, this may cause the CEL to operate. Check the gas tank cap and tighten it tightly if you find it is loose. After a while, the light will go out. If so, you have probably fixed the problem. Consider yourself lucky.

Problems That Can Cause the Check Engine Light to Work

If it's not the gas tank cap, there are other possibilities:

• Engine misfires that can cause the catalytic converter to overheat
• Oxygen sensor (regulates the air-fuel mixture)
• Air mass sensor
• Spark plug

Warning lights on the dashboard

What if my CEL is on because my vehicle's emissions system is not working?

Some drivers don't need a repair bill if they emit a little more pollutants. (We're not here to shame anyone for their carbon footprint.) But that's shortsighted. When your emissions system isn't working, it's not an isolated problem. If ignored, the problem can be more expensive. It's always best to investigate at the first sign of trouble.

Required maintenance is not the same as Check Engine

These two warnings are often confused. A required service alerts the driver that it is time for scheduled maintenance. This does not mean that something is wrong. The Check Engine light indicates a problem that is not related to scheduled maintenance. However, be aware that neglecting scheduled maintenance can create problems that can trigger the indicator.

Let's talk about other important dashboard warning lights.

Battery

Lights up when the voltage level is below normal. The problem may lie in the battery terminals, the alternator belt, or the battery itself.

Coolant Temperature Warning

This light is activated when the temperature is above normal. This may mean that there is too little coolant, there is a leak in the system, or the fan is not working.

Transfer temperature

This may be due to a coolant problem. Check both your transmission fluid and coolant.

Oil pressure warning

Oil pressure matters a lot. Check the oil level immediately. If you're not sure how to check your oil, refer to your owner's manual or stop by Chapel Hill Tire for an oil change today.

Airbag error

A problem with the airbag system requires the help of a professional. This is not something you should be trying to fix on your own.

Brake system

This could be caused by a low brake fluid level, the parking brake applied, or brake failure.

Traction Control/Electronic Stability Program (ESP)

When the anti-lock braking system detects a problem, this indicator will illuminate. Your braking system is not something to be ignored.

Tire Pressure Monitoring System (TPMS)

Tire pressure monitoring systems have saved countless lives by preventing tire-related accidents. They also make car maintenance much easier. Because of this nifty tool, many young drivers don't know how to check tire pressure the old-fashioned way. This was not a standard feature on US vehicles until it was introduced in 2007. Newer systems give you a real-time report of accurate pressure levels. Older systems light up if the tire pressure drops below 75% of the recommended level. If your system only reports a drop in pressure, it's a good idea to check your tire pressure regularly. Or let our tire fitting experts do it for you.

Low Power Warning

When the computer detects this, there are many possibilities. Your Chapel Hill Tire Service Technician has professional diagnostic tools to pinpoint the problem.

Security Alert

If the ignition switch is locked, this may flash for a second until it disappears. If you can start the car but it stays on, there may be a security problem.

Diesel Vehicle Warnings

Glow plugs

If you borrow your friend's diesel car or truck, he or she should explain how to start it. Diesel engines have glow plugs that must be warmed up before starting the engine. To do this, you turn the key halfway and wait until the glow plug indicator on the dashboard goes out. When it turns off, it is safe to start the engine.

Diesel Particulate Filter (DPF)

This indicates a problem with the diesel particulate filter.

Diesel Exhaust Fluid

Check the diesel exhaust fluid level.

Chapel Hill Tire Diagnostic Service

Did you know that every tenth car in operation has a CEL? We hope your car is not one of them. Let's take care of the problem. Visit our location page to find a service center near you, or book an appointment with our experts today!

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