Error Messages and Warning Lights in GM Cars (Chevy, Buick, Cadillac, Pontiac, GMC)

While Chevrolet and other General Motors cars are considered to be reliable and durable, some of them will struggle to prove this point in real life. The number of different error messages you can see popping up on the dash is enormous.

And I decided to brush up on what we've been writing here, at Cararac, for a long time. In this article, I will promptly tell you about all the common error messages and warning lights that you can deal with in Chevrolet and GM vehicles.

Let's see what the reasons for them are and how to fix them!

"Service StabiliTrak" message in Chevrolet/GM

All General Motors vehicles have a system called StabiliTrak. This is the stabilization system that allows you to easily maintain the proper stability on the road. This system includes a whole bunch of different subsystems, sensors, and actuators. Once something goes wrong, you will see the "Service StabiliTtrak" error message.

While it's common for Chevy cars, it's possible to see in all other GM vehicles and the fixes will most likely be the same for all models. You will need proper scanner tools to dig into the codes and find what exactly is causing the issue. This is not just that simple and the cheap ELM scanner won't help.

It's important to notice other symptoms that accompany this warning. For example, the car may shake or it may refuse to start. Noticing the symptoms will help you locate and solve the problem.

Also, I've seen the limp mode activating when the StabiliTrak system is inactive. In this case, the message will also say "Engine Power Reduced".

Service StabiliTrak message highlights:

• Common reasons:any stabilization system component is faulty
• How to fix:scan for error codes to know the problem
• Possible consequences:the vehicle may eventually stop and you may be stranded
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$150-$1,000

"Steering Assist Is Reduced, Drive with Care" message in Chevrolet/GM

While this message was originally designed to inform you about the faulty power steering system, in most cases, it indicates the problems with the 12V battery or the issues with the software in your car.

I would recommend checking the battery in different conditions and ensuring that it's OK. If the problem is not with the battery, you should go to the dealer and ask them to check whether there are some worth-to-install software updates that they can apply to your car.

In very rare cases, this message can actually mean that the power steering needs attention. Usually, it's about older cars with high mileage on them. Also, you need to be careful when you see this message because you may lose some part of assistance in turning the steering wheel and it can become extremely stiff.

Steering assist is reduced message highlights:

• Common reasons:battery problems, software glitches, bad power steering
• How to fix:check the battery, update the software, use the scanner to read codes
• Possible consequences:loss of power steering
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$0-$900

"Service Power Steering" message in Chevrolet/GM

Even though the "Service Power Steering" message sounds very straightforward, it may mean different things. Like with the previous message, this one can pop up because of the faulty battery or issues with the software.

It still can mean that the electric power steering is having a fault in your vehicle and if you see this message, you should drive carefully. It's not guaranteed, but the power steering may become less efficient once you see this message and you may need to put more effort in when turning the steering wheel.

But the power-steering message is still not that straightforward and requires a good scan tool that can communicate with the power steering control module, not just with the ECU.

Service power steering message highlights:

• Common reasons:battery problems, software glitches, bad power steering
• How to fix:check the battery, update the software, use the scanner to read codes
• Possible consequences:loss of power steering
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$0-$900

"Anti-Theft System Problems" message in Chevrolet/GM

If you are getting the "Anti-Theft System Problems" message, it means that the vehicle registered issues with the security equipment like the alarm, locks, sensors, etc.

Also, this problem is very often an indication of the low battery. Once the battery voltage drops to below-normal readings, the vehicle may start glitching and the security system alerts are one of the possible warnings you may see, in this case.

Unfortunately, it's impossible to correctly say which module should be replaced or repaired just by looking at the message. You will need a good GM scanner to read the exact codes behind this message and to see if this can be repaired on your own.

Anti-theft system problems message highlights:

• Common reasons:battery problems, security equipment issues
• How to fix:check the battery, read the codes to know where to look
• Possible consequences:no serious consequences
• Priority level:Medium
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$150-$500

"Service Theft Deterrent System" message in Chevrolet/GM

This is yet another wording for the security system problems. Whenever you see the "Service Theft Deterrent System" message in your car, you may be sure that the security equipment is not working properly. As I've just explained above, this very often happens when the 12V battery is not perfect. Or it may denote some security problems like bad locks, door sensors, alarm issues, etc.

Service theft deterrent system message highlights:

• Common reasons:battery problems, security equipment issues
• How to fix:check the battery, read the codes to know where to look
• Possible consequences:no serious consequences
• Priority level:Medium
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$150-$500

"Service Battery Charging System" message in Chevrolet/GM

If you see the "Service Battery Charging System" error message in your Chevy or other GM-brand vehicle, it means that the 12V battery isn't getting the proper charge. There are several reasons why it can happen.

First of all, the alternator may be faulty and it may not be sending the proper voltage to the system. Secondly, the wires may be corroded, broken, or the connections may be loose. Also, the battery terminals may get some buildups and lose connection.

But sometimes, the problem is in the battery itself. In this case, the battery may be about to die, so it can't take the charge. And the battery management system is fooled into thinking that the alternator is faulty. Anyway, you will need to check all electrical equipment.

Service battery charging system message highlights:

• Common reasons:alternator issues,battery problems, loose wiring
• How to fix:check the battery, check the alternator, check the wires and connections
• Possible consequences:complete battery loss, inability to start the engine
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$0-$1,000

"Charging System Failure" message in Chevrolet/GM

This is exactly the same message that I've just explained above but with different wording. The charging system is the system that charges your battery, so when you see the "Charging System Failure" in your vehicle, you may be sure that the problem is somewhere between the alternator and the battery or exactly in these two units.

Charging system failure message highlights:

• Common reasons:alternator issues,battery problems, loose wiring
• How to fix:check the battery, check the alternator, check wires and connections
• Possible consequences:complete battery loss, inability to start the engine
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$0-$1,000

"Engine Power Reduced" message in Chevrolet/GM

If your General Motors vehicle says "Engine Power Reduced", there is a high chance that you have an electrical problem, a dirty throttle body, an issue with the battery or alternator, or just a temporary glitch in the vehicle's software.

It means that the vehicle entered the limp mode and you will only be able to use the small part of its initial power. It still doesn't mean that you can't drive. Also, very often, this message will clear itself quickly and the power of the vehicle will come back to you.

Usually, the ECU will store one or several codes that initially triggered this message. After reading the codes, you will be able to say for sure what exactly the problem is about, and fixing the car will be much more efficient.

Engine power reduced message highlights:

• Common reasons:electrical problems, dirty throttle, glitch
• How to fix:check the battery and alternator, check the throttle, read the codes
• Possible consequences:limp mode, no power, stalling
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$0-$500

"Service Traction Control, Engine Power Reduced" message in Chevrolet/GM

While the Engine Power Reduced means that your GM vehicle is in limp mode, the "Service Traction Control" part of the message should give you hints on what you should look at. But it actually appears to be even more deceiving and misleading.

The traction control system is a huge piece of equipment that embraces hundreds of sensors and many units of your car to keep the proper stability and traction of the vehicle on the road. The system may throw codes and messages in different cases. For example, when one of the wheels-speed sensors is faulty, or when the throttle flap is contaminated.

There are dozens of sensors that can trigger this message, so it's only possible to say something more specific after proper diagnostics. Also, you may or may not see the traction control light illuminating when this message is on the dash.

Service traction control message highlights:

• Common reasons:hundreds of reasons are possible
• How to fix:read the codes to narrow down the possible problems
• Possible consequences:limp mode, stalling, harsh engine work
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$150-$1,000

"Service Hybrid System. Stop the Vehicle in a Safe Place" message in Chevrolet/GM

If you are getting the "Service Hybrid System" message in your Chevrolet, you should check the codes in different control modules as soon as possible. There are several codes that open the 15-year warranty for hybrid systems in Chevy and other GM-brand vehicles.

In some cases, this message may appear when there are issues with the cooling of your hybrid assembly. It may overheat when the fan is faulty and doesn't engage when needed, so the system will throw the code and message.

Another weird thing is that the "Service Hybrid System" may often pop up on the dash after you brake sharply. In this case, the system is overloaded and can have a glitch. In this case, just turn the car off and then on to reset the code.

And lastly, if there are problems with the 12V battery, it can sometimes trigger this message by mistake. Replacement of the small battery will help.

Service hybrid system message highlights:

• Common reasons:hybrid system fan, sharp braking, connection problems
• How to fix:check the 12V battery, check the fan, restart the car
• Possible consequences:vehicle may die, hybrid system may overheat
• Priority level:High
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$0-$900

"Service Emission System" message in Chevrolet/GM

The "Service Emission System" is a pretty common message for any high-mileage diesel car made by General Motors.

The problem is that diesel vehicles have DPF filters to gather soot. If you drive your truck or SUV mainly in the city and the engine doesn't rev up high at all, this leads to DPF clogging. Sooner or later, the filter will be completely clogged and the planned regen won't help much.

This is the case for the Service Emission System error message. But it's not the only possible reason. There are also dozens of other conditions that can trigger this warning.

Service emission system message highlights:

• Common reasons:DPF clogged, problems with emission sensors
• How to fix:try manual regen, try driving at high RPM
• Possible consequences:vehicle may go to limp mode, engine may eventually stall
• Priority level:High
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$0-$2,500

"Service 4WD" message in Chevrolet/GM

This is a scary message because problems with 4WD systems are extremely expensive to fix. But in GM cars, it's sometimes just a simple problem with zero-dollars fix price.

In most cases, this can be caused by the transfer case control motor or control module. Also, there are chances that the 4WD switch is causing the problem. You need to verify that the transfer case wiring is OK and that the ground is clean and properly attached.

Other than that, there are dozens of way fewer possible problems that can still trigger the Service 4WD message. I strongly recommend using a good scanner before starting to fix anything.

Service 4WD message highlights:

• Common reasons:transfer case control module, control motor, wiring, ground, 4WD switch
• How to fix:get the error codes before repairing your vehicle
• Possible consequences:4WD may overheat and get a fatal problem
• Priority level:High
• Can you drive?Carefully and slowly
• DIY repair:Possible but complicated
• Repair price range:$0-$3,000

"Engine Hot, AC Off" message in Chevrolet/GM

While the primary task of the "Engine Hot, AC Off" error message is to inform you that the air conditioner is automatically deactivated, the more important thing is that the engine is overheated.

But this message doesn't always mean that the engine temperature is actually high. In most cases, the temperature gauge will show zero when you see the message on the dash and this means that the engine temperature sensor is malfunctioning.

First of all, when you see this message in your Chevy or other GM vehicle, verify that the coolant is at a normal level. If it is, look at the temperature gauge - is it showing zero? If yes, you most likely have the broken engine temperature sensor or one of the wires fell off.

Engine hot, AC off message highlights:

• Common reasons:no coolant, engine temperature sensor dead
• How to fix:check coolant level, check temp sensor
• Possible consequences:overheated engine will die quickly
• Priority level:High
• Can you drive?Not recommended
• DIY repair:Possible
• Repair price range:$100-$450

"Service ESC" message in Chevrolet/GM

The ESC or Electronic Stability Control embraces a ton of different sensors and features in your vehicle. This is quite like the Traction Control System but with some extra features to be considered.

So, it's completely impossible to guess what exactly is malfunctioning when you have the "Service ESC" message on the dash of your car. In most cases, this is connected with wheel-speed sensors, half-shaft sensors, steering wheel angle sensor, or something else that tells the ECU what's going on with the wheels and steering wheel position.

Also, it has something to do with the throttle position and other units that control the engine work.

Anyway, you will need a good GM scanner to read all the codes, not just the ECU codes, and make a conclusion about what can actually malfunction.

Service ESC message highlights:

• Common reasons:a ton of reasons including ABS sensors, steering wheel angle sensor, throttle, etc.
• How to fix:read the codes in all control modules to make the conclusion
• Possible consequences:stability of the car may be affected, safety may be affected
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible but complicated
• Repair price range:$150-$800

Code 84 message in Chevrolet/GM

If you see the Code 84 message on the dash of your General Motors car, it means that you need to pay attention to other warning lights and messages. This is a generic code meaning that something is wrong with the vehicle.

There are usually other codes in the ECU and other control units behind this message. But the actual task of this code is to draw your attention and show you that something is wrong with your car.

Obviously, you will need a good GM scanner to get those trouble codes out and find out the actual reason for what is malfunctioning in your car. After that, you can decide how you want to repair the vehicle. Sometimes, just disconnecting the battery and resetting the codes will help.

Code 84 message highlights:

• Common reasons:any other code in control units
• How to fix:read the codes and see what triggers the message
• Possible consequences:depends on what initially triggers the message
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Possible
• Repair price range:$150-$500