Common Error Messages and Warning Lights in Various Car Brands

While most car brands try to design their unique error messages, some vehicles still use generic warnings. You can usually see them in different cars, so I couldn't put them into any other category but this one.

In this article, I will tell you about the warning lights and error messages that you can see in various cars. I will also give you links for proper investigation of the problem. Here, I will just give you certain outlines about the actual problems causing these issues and also about the ways to fix the problem.

"Transaxle Control System Malfunction" message

This is not the error message you can see on the dashboard, but the code P0700 (in most vehicles). This code and message will only be seen after you use the OBD2 scanner and get the code.

So, the "Transaxle Control System Malfunction" message usually means that your transmission control module is malfunctioning. In most cases, this is all about the glitches and electrical problems inside the module. But sometimes, this may mean that the module is shorted or disconnected.

The obvious fix is to check the connections of the transmission control module and also to verify it's working properly.

Transaxle control system malfunction message highlights:

• Common reasons:transmission control module glitch or failure
• How to fix:disconnect the module for some time, check connections, replace it
• Possible consequences:transmission may not work properly
• Priority level:High
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$350-$1,700

"Collision Mitigation System Problem" message

The collision mitigation or collision prevention system is a set of units working together to brake automatically and/or alert the driver about the possible impact on the road.

This system uses the radar sensor in the front and sometimes in the rear part of the car, and also optionally it uses the camera. Once one single module in the system is blocked or malfunctioning, the system may throw the message saying "Collision Mitigation System Problem".

If you see this, try cleaning the radar and camera areas, turning the vehicle off and on, or disconnecting the battery for some time. Also, awful weather may be the reason for the problem.

Collision mitigation system problem message highlights:

• Common reasons:radar sensor or camera blocked, software glitch
• How to fix:clean radar and sensor areas, disconnect the battery for some time
• Possible consequences:smart functions won't be working
• Priority level:Low
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$0-$450

"Service DEF System" message

When you see the "Service DEF System" message in your vehicle, it means that the diesel exhaust fluid injection is not working properly.

Sometimes, it just means that you will need to add DEF to the tank. But, in most cases, such a message means that the problem is more serious, like the broken DEF injector, clogged injection system, wrong fluid in the tank, etc.

Usually, reading the codes behind this message may help you. Also, you may address forums and read about the common issues that may trigger this message exactly in your vehicle model.

Service DEF system message highlights:

• Common reasons:DEF injector issues, DEF quality problem
• How to fix:add DEF, read the codes
• Possible consequences:engine may lose power soon
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$20-$500

"Exhaust System Regeneration in Process" message

When you see the "Exhaust System Regeneration in Process" message, the DPF is pretty clogged and maybe about 80% full. So, the best solution for this situation is to keep driving at quite a high RPM. You may even want to take another lap on a highway to clean the DPF.

The thing is that when you drive in the city, the DPF is not getting cleaned properly and the regeneration process is not carried out well. So, sometimes, a modern diesel car needs good frying to clean that soot from the DPF by burning it.

This message doesn't mean that there is a problem. But if it's ignored, the problems will come soon.

Exhaust system regeneration in process message highlights:

• Common reasons:DPF almost full, regeneration is being carried out
• How to fix:keep driving, start manual regeneration
• Possible consequences:DPF may be clogged and require cleaning
• Priority level:Medium
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$0-$250

"Service ESC" message

ESC stands for Electronic Stability Control. This is the system that controls the traction of your car and prevents it from skidding. If you see the "Service ESC" message on the dash of your vehicle, one of the components of this system requires attention.

The ESC relies on many sensors including wheel speed sensors, steering angle sensor, throttle sensors, etc. Also, this system has its own control module that may also malfunction and throw this message.

After reading the codes, you may narrow down the problem and find the most appropriate solution that will work in your case.

Service ESC message highlights:

• Common reasons:one of the ESC components is in trouble
• How to fix:read the codes, disconnect the battery for some time
• Possible consequences:stability control will not work
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$150-$600

Check Engine Light

The check engine light is one of the most commonly seen warning lights in modern vehicles. This is the light that informs you about the possible codes in the ECU or other important control modules.

Usually, the best solution when you see this light is to read the code stored in the ECU and understand what exactly it tries to tell you. The CEL will often light up on the dash of your car just because there is a very minor issue or even a software glitch that requires a reset. In this case, just disconnecting the battery cables for some time will help. Or you may wait till the light decides to go off on its own.

In some cases, it may illuminate on the dash in certain conditions. For example, the CEL may appear after you accelerate to a certain speed. This may mean that the catalytic converter overheats and the oxygen sensor throws the code.

Another issue is when there is no check engine light when you are starting the car. It should be on for several seconds. In this case, it's wise to go to a professional mechanic and check the ECU for minor problems.

Check engine light highlights:

• Common reasons:vast choice of different problems
• How to fix:read the codes to narrow down the issue
• Possible consequences:depends on the actual culprit
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$150-$1,000

Circle with Exclamation Mark Inside warning light

Usually, the circle light with an exclamation mark inside it means that there are issues with the braking system of your car. It may also mean that the parking brake hasn't been released, so check this, in the first place.

If the problem is with the braking system, there are numerous things that may trigger this light like low fluid level, worn-out brake pads, issues with ABS, etc.

But there are also other warning lights that can be described as the circle with exclamation mark inside it. Hope you will find the proper light in my article.

Circle light with exclamation mark inside highlights:

• Common reasons:braking system problem, parking brake engaged, ABS issues
• How to fix:check parking brake, check brake fluid, have the car inspected
• Possible consequences:braking may lose efficiency
• Priority level:High
• Can you drive?Not recommended
• DIY repair:Impossible
• Repair price range:$250-$800

Warning light A with arrow

If you see the warning light circled by the arrow with the letter A inside it, it means that the start-stop system is not working properly. This light means that the vehicle won't turn off the engine and it won't automatically turn on.

There are a lot of things that may trigger this light in your vehicle. First of all, it's the lack of electrical power because of the poor battery. Also, the start-stop error will come on the dash when the vehicle has issues with the throttle control or just when the AC hasn't yet achieved the needed temperature.

Sometimes, this may have something to do with the engine temperature or other factors that affect the work of the engine.

Triangle warning light highlights:

• Common reasons:issues with start-stop system, start-stop can't activate
• How to fix:drive further, check 12V battery, read the codes
• Possible consequences:start-stop won't work, battery may die
• Priority level:Medium
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$0-$550

Triangle warning lights with arrow around it

When you see the triangle warning light with exclamation mark and the circled arrow, it means there are issues with the stability systems like ESP, TCS, ESC, ATC, etc. This light may be triggered by a large number of different codes in various control modules.

One of the most common culprits is a wheel-speed sensor. Also, the ABS module may malfunction. I've seen this light coming on the dash when tire pressure wasn't perfect. There are so many factors that influence the work of the traction control and stability control systems that it's almost impossible to guess.

Also, to read the codes triggering this light, you will need to have a good professional scanner that can communicate with various control modules, not just the ECU.

Also, you may see the car with squiggly lines light. Alternatively, there may be the TC light with a slash through it. They all refer to traction control problems.

Triangle warning lights with arrow highlights:

• Common reasons:any problem with traction control
• How to fix:read the codes, check the obvious possible issues
• Possible consequences:traction control may not work
• Priority level:High
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$150-$450

Transmission light blinking

If you see the transmission light blinking, it certainly means that there are issues with the transmission control module or the transmission itself. Usually, in most cars, it's the gear light with the exclamation mark inside it.

The light is important and shouldn't be ignored by the driver. Driving the car further may eventually cost you several thousand dollars if the problem is with the low level of transmission fluid or some internal damage.

When the transmission light is blinking, it may mean almost anything including even light damage of the control module or software glitch. Unfortunately, checking this without a professional scanner is impossible, so towing is recommended.

Transmission warning light highlights:

• Common reasons:issues with the transmission or transmission control module
• How to fix:get the car towed to the dealership or repair shop
• Possible consequences:transmission may break
• Priority level:High
• Can you drive?Not recommended
• DIY repair:Impossible
• Repair price range:$300-$4,500

Battery light flickering

The battery light should only go on when you are starting the car. It shouldn't light up after that and of course, it shouldn't go flickering. If this happens, you most likely have a problem with the charging system in your car.

The charging system embraces everything that is connected to the battery: the battery itself, the wires, the alternator with the serpentine belt, and also the voltage regulator. Every single unit of the listed ones can cause the battery light anomalies in your vehicle.

If you see this, you should quickly find the place where you can check the car or have it repaired. Otherwise, you may get stranded very soon because the battery will completely die.

The battery light can only be red, which means that the problem is always urgent and shouldn't be ignored.

Flickering battery light highlights:

• Common reasons:battery, alternator, voltage regulator, wires, serpentine belt
• How to fix:check the battery and the alternator, have the car inspected
• Possible consequences:battery may quickly die
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$200-$550

Service 4WD warning light

When your car is developing problems with its 4-wheel-drive or all-wheel-drive system, you will definitely see several warning lights and the control modules will save several codes. One of the most common lights, in such cases, for off-road vehicles is the Service 4WD light.

It doesn't mean anything in particular but tells you about the possible problem with a differential, transaxle, various sensors, switches, and other things that have something to do with the 4-wheel drive.

Also, the same works for the AWD warning light that you will mostly see in SUVs, not real off-road cars. If you see this, it's always better to stop driving and inspect the car. Driving further may hurt the expensive units and make you pay much more eventually.

Service 4WD light highlights:

• Common reasons:4WD or AWD problems, software glitch
• How to fix:try disconnecting the battery for some time, have the car inspected
• Possible consequences:all-wheel-drive units can die
• Priority level:High
• Can you drive?Not recommended
• DIY repair:Impossible
• Repair price range:$400-$1,500

Yellow Key warning light

If you see the yellow key light on the dash of your car, it means that the vehicle can't identify the key fob. In most cases, it means that the key fob battery is dead. Sometimes, it may also mean that your vehicle has a broken antenna for the keyless entry system, or there is a glitch.

I would start by replacing the key fob battery. The second thing, if this one doesn't help, would be to check the 12V battery voltage. After that, I would take the car in for the inspection as there are no other DIY things you can easily do.

The yellow key sign on the dash may be bypassed. Every car has the option to start a car using the manual key or the specially designated place to put the key fob. Just get the instructions in the driver's manual.

Yellow key warning light highlights:

• Common reasons:key fob battery is dead, issues with electronics
• How to fix:replace the key fob battery, check the 12V battery
• Possible consequences:car won't start with the button
• Priority level:Low
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$5-$200

ETC warning light

The ETC warning light or the lightning bolt light is an indication of the electronic throttle control problem. The majority of modern vehicles have the electronic throttle which means there is no physical connection between the gas pedal and the throttle flap.

If one of the sensors or switches goes bad, it's natural for the ECU to lose control over the throttle. So, it will throw this light immediately.

You will not always lose the possibility to drive the car when it happens. There are some ways for your car brain to bypass the problem and allow you to limp to the dealership or home. But sometimes, this can actually make you stranded.

ETC warning light highlights:

• Common reasons:throttle control problems, sensors or switches issues
• How to fix:read the codes, take it in for inspection
• Possible consequences:you may not be able to control the throttle
• Priority level:High
• Can you drive?Yes, if possible
• DIY repair:Impossible
• Repair price range:$200-$550

EPS warning lights

EPS stands for Electronic Power Steering. So, the EPS warning light means that you have a problem with power steering in your car. And this problem can't be solved by simply adding some extra fluid (because there is just no power steering fluid in your car).

The EPS warning means that the vehicle just doesn't have full control over the power steering. Some sensors may have died or the actuators in the system are malfunctioning. But sometimes, it's all about the electronic glitches.

You should start by disconnecting the battery for some time to reset the system. Also, check if the battery and the alternator are doing well. Sometimes, it's them who are in charge of the problem.

EPS warning light highlights:

• Common reasons:electronic power steering issues, software glitch
• How to fix:read the codes, disconnect the battery for some time, check the battery and alternator
• Possible consequences:power steering may not be available
• Priority level:High
• Can you drive?Very carefully
• DIY repair:Impossible
• Repair price range:$200-$850

Brake fluid warning light

Some vehicles have a separate light for brake fluid level. This is not that common nowadays because the majority of problems will be displayed by the brake system problem light. Still, it's worth knowing what it looks like and what to do when you see it.

So, the brake fluid level warning light will come on the dash when the level of brake fluid is critically low. Driving further without checking everything is deadly dangerous. Adding fluid to the tank and carefully driving for about one mile, then checking again, is the only safe choice.

Also, you may want to look for any leaks around the wheels and under the hood. This may help you find the reason for the light. If there are leaks in the braking system, driving further is not possible at all.

Brake fluid warning light highlights:

• Common reasons:brake fluid level low, bad sensor
• How to fix:check brake fluid level, look for leaks
• Possible consequences:brakes may not be available
• Priority level:High
• Can you drive?No
• DIY repair:Impossible
• Repair price range:$20-$550

"Engine derate in 3 hours" warning

In heavy trucks and other commercial vehicles, you may see the "Engine derate in N hours" warning where N can be any number. This means that the vehicle has problems with the emission control system and the problem has to be solved as soon as possible.

The DPF may be clogged or the DEF may be empty. So, if you just keep driving, after 3 hours the engine power will be significantly reduced. When this happens, you will only be able to limp at the speed of 5 or 10 MPH. So, this problem is urgent and has to be solved before the engine actually loses its power.

Engine derate in 3 hours message highlights:

• Common reasons:emission control system problems
• How to fix:use manual regen, add DEF, read the codes
• Possible consequences:engine may lose power
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$50-$1,000

"Poor DEF quality Detected" message

DEF stands for Diesel Exhaust Fluid. This is the fluid that serves as the catalyzer for several exhaust gas components. It works to significantly reduce the level of harmful emissions in diesel cars.

Usually, the "Poor DEF quality Detected" message will come on the dash when there is a problem with the DEF system. Maybe, the injector is faulty, or maybe there is an issue with the level of DEF in the tank.

If adding DEF doesn't help you solve the problem, the best solution would be to go to the dealership and ask mechanics to read the codes and change the DEF in the tank. After driving for several miles with clean DEF, this message should be gone.

Poor DEF quality detected message highlights:

• Common reasons:low DEF, issues with DEF injection, bad DEF
• How to fix:add DEF, have the car inspected
• Possible consequences:engine may go to limp mode
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$50-$250