Dash Warning Lights Only Provide A Warning, Something Is Wrong

Dash Warning Lights Only Provide A Warning, Something Is Wrong
Dash Warning Lights Only Provide A Warning, Something Is Wrong

Most dash warning lights, tell you that a fault has occurred, inside the vehicle’s system.

So, dash warning lights provide an idea – sometimes precise, sometimes vague – of what’s wrong with a vehicle.

Because, dash warning lights, are only the messenger to something going on. And, does not pinpoint the item or system that has failed.

So, some dash warning lights point to, relatively small issues. But, some of the issues, are major. Unfortunately, there is no way to distinguish between them, by just looking at, the warning light.

Abbreviations, that will be used in this Blog Post will include:

  • On Board Diagnostics (OBD)
  • Diagnostic Trouble Code (DTC)
  • Electronic Control Unit (ECU)
  • Check Engine Light (CEL)
  • Malfunction Indicator Light (MIL)
  • Body Control Module (BCM)
  • Anti-lock Brake System (ABS)
  • Traction Control System (TCS)
  • Tire Pressure Monitoring System (TPMS)
  • Evaporative Emission System (EVAP)
  • Electronic Stability Control (ESC)

Today, (OBD) scan tools, can talk to your vehicle. And, bring back information in the form of, Diagnostic Trouble Codes (DTC)s.

Dash Warning Lights
On Board Diagnostics (OBD) scan tool

So, the scan tool and accompanied software, can read the (DTC), from the Engine Control Unit (ECU). Also, every time the (OBD) system turns a warning light on, it will also store, a (DTC) in the (ECU). Finally, the (DTC), will give more information about the detected issue.

NOTE: Many parts stores will read the (DTC) for you, at no cost.

So, dash warning lights are nothing new, but the messages are. Today, there are hundreds of different, dash warning lights. And, not all dash warning lights are universal. So, always refer to your owner’s manual, when you’re not 100% sure, what the light means.

Dash Warning Lights
Hundreds Of Different Dash Warning Lights

The Following List Of Dash Warning Lights, Are The Most Common:

Check Engine Light (CEL) Or (MIL), Warning Light

So, a warning light coming on, shows that the (ECU), has set a (DTC). And, usually requires diagnosis, with a professional scan tool.

Dash Warning Lights
Check Engine Light

The Warning Light Can Signal, Three Different Types Of Problems:

  1. Occasional flashes, indicate temporary engine malfunctions. Consequently, you should be aware of the possible upcoming issues, which can later turn to more serious ones.
  2. The most common case, is when the warning light, stays on constantly. This refers to a more serious problem. Yet, sometimes the issues aren’t that serious. But, can affect the emissions of the vehicle.
  3. The most serious type of warning is, when the light,  flashes all the time. It is a sign that your vehicle’s engine is misfiring. Because, this issue is a major one, you should stop the engine immediately, to prevent serious damage.

Battery/Charging Alert

Most vehicles have an alternator, along with a voltage regulator, that keeps the battery charged. And, also provides electricity to the vehicle, when the engine is running. A simple circuit looks at the voltage that the alternator is producing. And, turns the battery light on, if it is low.

Also, means voltage level is below normal level, and the vehicle’s charging system is not working properly. So, check battery terminals, alternator belt, and battery condition. Again, dash warning lights, are only the messenger.

Engine Coolant Light

If you see the engine coolant light show up on your dashboard, it could mean coolant levels are running low. So, check the gauge on the side of the coolant tank, under the hood and top up if necessary. In conjunction with a temperature gauge reading well into the red, it could mean your engine is overheating.

Engine Coolant Hot
Engine Coolant Hot

This light lets you know the temperature has, exceeded normal limits. So, you need to check the:

  • Coolant level
  • Fan operation
  • Radiator cap
  • Coolant for leaks

Transmission Temperature

Transmission is operating at higher than optimum temperature, as transmission fluid is, hotter than normal. Check transmission fluid and engine coolant levels.

Oil Pressure Warning

STOP driving immediately and turn the engine off.

Possible Causes Of A Low Oil Pressure Warning Light Include:

  • A low oil level (check the dipstick)
  • Bad oil pump
  • Defective oil pressure sending unit
  • Oil pressure gauge or warning light switch

If this light stays lit, it means there is a loss of oil pressure. Immediately check oil level and pressure.

Oil Change Reminder

This Is Monitored By, The Engine Control Unit (ECU). And, Lets You Know That The Oils Lifespan Has Expired.

So, the interval can be mileage or a combination of readings, taken by the Engine Control Unit (ECU). The owner’s manual lists the reset procedure. Some vehicles require the use of special tools, to reset the light.

When you first start the engine, the “oil change due” light should come on, for 1 to 2 seconds. But, if the light stays on, the vehicle is due for an oil and filter change.

Service Vehicle Soon

Typically show, a lighting or other electrical problem, that is controlled by, the (BCM). Check all lights (headlights, turn signals, brake lights, and hazard lights). Again, dash warning lights, are only the messenger.

Service Vehicle Soon Light
Service Vehicle Soon Light

The light comes on when, there is a fault condition in an area of, the vehicle chassis systems.

These systems may include:

  • (ABS) System
  • (TCS) System
  • The Electronic Suspension System
  • Brake Hydraulic System

Tire Pressure Monitoring System (TPMS)

So, the (TPMS), has found a tire with low air pressure. And, there may also be, a sensor malfunction. First, check tire pressure. Also, some vehicles will allow a manual reset, of the Tire Pressure Monitoring System warning light. But, others will require, a professional diagnosis. So, refer to owner’s manual.

Brake System

When Lighted, points to one of three possible conditions:

  • Parking brake is on
  • Problem with the braking system or brake fluid is low
  • (ABS) problem

But, if the problem is in the (ABS), it may need professional diagnosis.

Reduced Engine Power

Means the Engine Control Unit (ECU), has limited the engines power output. Reduced engine power is a protective mode, that slows your car down and limits acceleration. Low engine oil, loose cables, and a clogged catalytic converter commonly cause, reduced engine power.

Reduced Engine Power
Reduced Engine Power

Consequently, the Engine Control Unit (ECU) has many levels of reduced power. And, it all depends on what part has failed, in its control system. And, usually requires diagnosis, with a professional scan tool. Again, dash warning lights, are only the messenger.

Anti-lock Brake System (ABS) Light

Shows that the (ABS), has set a code and needs professional diagnosis.

So, the (ABS), uses sensors at each wheel to monitor their rotational speed. In addition, a computer monitors the signals, from all four wheels and the position of the brake pedal. This is to make sure that the vehicle, is stable and under control.

If the computer notices any abnormal signals, or the lack of a signal from any of the sensors. Then, it will turn the (ABS) light on, to alert the driver of an issue. In addition, to monitoring the wheel speed sensors, the computer can turn the (ABS) light. Also, there are other reasons. For example, low brake fluid levels or a blown fuse.

Gas/Fuel Cap

Consequently, if your fuel cap light is on, it means that the computer has, detected a leak in the system. Usually, from a loose gas cap. A leak present somewhere else in the system, can also trick the computer into thinking, the gas cap is leaking. And, in turn can affect the, (EVAP) System.

Check Gas Fuel Cap Light
Check Gas Fuel Cap Light

So, if not addressed quickly, a warning light, will also light up. Again, dash warning lights, are only the messenger.

Cruise Control

Tells you that, the cruise control is set during driving.

Electronic Stability Program (ESP) System

This system works in conjunction with others, such as the:

  • (TCS) System
  • (ABS) System
  • (ESC) System

And, is a crucial system because, it ensures stable driving, in all directions and lateral dynamics. In difficult driving situations, this prevents you from skidding and ensures that your steering, is as accurate as possible.

Security Alert

So, if the symbol lights momentarily, it may mean that, the ignition switch is locked. And, will need the proper transponder-equipped key to restart.

Dash Warning Lights
It May Mean That The Ignition Switch Is Locked

If the symbol is visible, when the vehicle is on, then it usually means, a malfunction in the security system.

Lamp Out

Shows that there is, an outside light on the vehicle, that is not working properly. Again, dash warning lights, are only the messenger.

Traction Control or (ESP)

This light Illuminates when, the vehicle’s (TCS)/(ESC) System is in use. Usually, an sign that, conditions are slippery.

Door Ajar

Tells you that a door (including hood and trunk) is not closed. Open and close all doors, including hood and trunk. Because, if vehicle is left in this condition overnight, it can drain the battery.

Overdrive Light

This symbol lets you know, that the vehicle’s Overdrive System, has been manually turned off. Typically, the Overdrive System is controlled by, an on/off switch.

Airbag Fault

So, if this light stays on after starting, it tells you the vehicle has, a fault in the Airbag System. As a result, the computer has set a code. Again, dash warning lights, are only the messenger.

The Vehicle Has Found A Fault In The Airbag System
The Vehicle Has Found A Fault In The Airbag System

Above all, professional repair of the supplemental restraint system, is highly recommended.

Washer Fluid Reminder

Tells you that the Washer Fluid is low. Fill washer fluid tank. The cap has a symbol, that looks like a windshield. Some vehicles have separate tanks, for front and rear window washers.

Fog Lamp

Lets you know, that the vehicle’s front fog lamps, are on.


So, it could be something as minor as, a faulty sensor or a broken wire. But, it could also be, something more serious than that. Therefore, if left unchecked, the faulty issue will cause, lasting and expensive damage to your vehicle. And, in certain cases, it can result in, total breakdown of your vehicle.

However, dash warning lights are not going to warn you that:

  • The water pump is about to fail.
  • That one of the ball joints is worn out.
  • Or even that the A/C is going to stop blowing cold air, in mid-August.

Finally, if your vehicle drives, sounds, or smells funny, either fix it or take it to someone who can.

Thank You !