Collision Warning and Intervention
Collision warning and intervention systems in the news. In August of 2022, six leading organizations that are committed to consumer safety and education — AAA, Consumer Reports, J.D. Power, National Safety Council, PAVE, and SAE — came together to develop the standardized naming conventions for Advanced Driver Assistance Systems (ADAS) technologies.
This post addresses Collision Warning and Collision Intervention System and Malfunction Indicators, a subset of ADAS. We address them directly below.
The newly recommended naming conventions are simple, specific, and based on system functionality. We have advocated for these changes for years and welcome them, but we will continue to include the old names where necessary.
Unfortunately the absolutely outlandish number of indicators used are not addressed! And the list continues to grow…
Further, it is important to note that the organizations are only asking automakers to adopt the standardized terminology, a move that would go a long way in reducing reduce consumer confusion about the intent and functionality of these systems. We’ll do our best to help here and in other posts.
PCS stands for Pre Collision, or Crash, System. FCW stands for Forward Collision Warning System. Another is CMBS or Collision Mitigation Brake System. Yet another is the very awkward sounding Pre-safe Seat Belt (PSB) system. This one has a warning image in the message center in gray scale, like the seated figure shown to the right, along with a text warning. How about Panic Brake Assist (PBA), Forward Emergency Braking (FEB), Predictive Forward Collision Warning (PFCW) or Smart Brake Support (SBS)? They play in the same ball park, but don’t have their own text symbols!
- Before continuing, is one of these truly your symbol?? If yes, then read on below.
- Otherwise, you can return to our main Text Symbols page and scan again!
The end result is yet another advanced system that has managed to resist finding a standardized name. The systems discussed here use radar while others use cameras, which can be found here.
These systems, and those that follow, are all moving in the direction of automatic braking, which all manufacturers have promised to install in all passenger vehicles by roughly 2020.
Regardless of name or acronym, the systems, if fitted, minimize the risk of injury if a crash becomes unavoidable. The vehicle will alter its suspension and brake settings (apply the brakes) and the front seat belts are tightened. If one of these indicator symbols is shown on your instrument cluster, it indicates a problem with the system and the vehicle should be taken to your dealer or authorized repair facility.
A more recent addition is this Emergency Steering Warning Light indicator, and is part of Forward Collision-Avoidance Assist (FCA). The system is intended to assist steering — and hence the steering wheel — to aid in avoiding a collision with an oncoming vehicle from the front or the side or if a pedestrian or other obstacle is detected. It will be seen in yellow/amber/orange when all or part of FCA is disabled or malfunctioning. It will blink in red when steering assistance is required.
Another recent (2024) addition is this Pre-Collision Assist indicator. Pre-collision assist detects and warns of approaching hazards in the road and provides multiple levels of assistance to help avoid a collision if you are rapidly approaching another stationary vehicle, a vehicle traveling in the same direction, or a pedestrian or cyclist in your path. The system offers an alert first, then brake support and automatic emergency braking, if needed.
The image with the line drawn through it says that the system is malfunctioning. Continue on for additional information regarding system problems.
Many More Versions
The images here are of a Collision Warning System active and another with the word OFF added, meaning the system has been deactivated. They are seen as a car in a lane with wavy lines radiating away in four directions. And the word OFF in the one case, all in red.
It is important to note that many systems can only warn of a potential collision audibly and take no active measures to protect you. Check your owners manual carefully. And regardless of whether the system is active or not, it should never be relied upon to avoid a collision without the driver’s help!
This symbol is a Rear Collision Warning indicator. While it resembles many of the symbols already seen on this post, it is specifically used to warn of a possible collision from behind. The difference is that the car in front is seen in full and the one behind is only partially visible. The roles are reversed in collision warnings with a car in front.
These two are Intersection Collision Warning symbols and warn of a possible collision from the side. They are always seen in red. Oddly, the first image is of the right side of a vehicle and warns of a possible collision on the left. And conversely the second indicator is of the left side of a vehicle and warns of a collision from the right!
A common problem is dirt on the sensors or cameras in the front of the vehicle and often a simple car wash or cleaning will resolve the issue. The symbol to the left showing an arrow piercing the top side of a car is used by manufacturers for what they call the City Safety System to indicate that sensors mounted in the windshield are blocked by dirt or debris.
The first symbol in this set also points to debris blocking the camera at the front of the vehicle, and again a car wash is likely all that is needed. This, and the next two symbols, are the only ones to attempt a representation of seeing. They are also in black and white and will be displayed in the information screen along with a text description of the problem. The image, unlike the next two gives no indication itself of a problem.
These next two do indicate a problem. The first to the left adds an exclamation point and indicates a fault with the forward facing camera. A qualified service shop will be needed. The second, with the line drawn through the car and the radiating lines, indicates that the camera is temporarily unavailable due to its temperature being too high or too low. Camera function will return when the proper temperature range is restored.
These symbols indicate that the Forward Collision Warning system has been turned off. Some manufacturers use the picture symbol with the word OFF, while others add OFF to the system’s acronym. The image symbols are intended to look like cars crashing into each other, and does the job.
The symbol to the left, which adds the exclamation point in the triangle alert and an arrow indicating the direction of travel, illuminates when the brakes are applied automatically, which would be an obvious distraction to the driver at a clearly bad time.
If any of these lights remain illuminated, it indicates a problem with the system that will require your dealer or authorized service center to resolve. The light to the left is a trouble light only. See your favorite service center. And note that if there are any additional illuminated warning symbols, most likely they will need to be addressed first.
These indicators to the left are Front-end Collision Warning indicators, although the symbols show the back-end of a car. The manufacturers use the same symbol for both a warning that the system has a problem or if a collision is imminent. We’ve shown them d, which is used when a potential collision is detected. It may flash red as the condition worsens and/or when the relative speed between the two vehicles is large.
It will illuminate in yellow/amber when associated with the Active Cruise Control system and a vehicle driving ahead is detected. The indicator will flash if the system is not operating properly. In this case, the active cruise control will be deactivated and the brakes will be applied until the driver resumes control by either pressing on the brake or accelerator pedal.
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Remember that only proper service and repair procedures will ensure the safe and reliable operation of your car. In addition, proper safety procedures and precautions, such as the use of safety goggles, the right tools and the equipment should be followed at all times to eliminate the possibility of personal injury or improper service which could damage the vehicle or compromise its safety.
These posts are for information sharing purposes only, and should not be used in lieu of an OEM service manual or factory authorized service procedure. We are not in the auto repair business nor do we publish automotive service manuals. Nothing we include on these pages and posts has been reviewed, approved or authorized by any vehicle manufacturer.
Technology is always changing and what is current and accurate today may be literally out-of-date and inaccurate tomorrow. And when it comes to the current state of flux in the auto industry, nothing is more true.
The author has 25 years of automotive experience and has assembled the most extensive collection of symbols and warning lights anywhere (over 1,000!) and can help you open and start any keyless start car with a dead key fob battery. BA, St. Joseph’s College, ME: MS, Rensselaer Polytechnic Institute, NY
These are all Slip Indicator and Electronic Stability Control (ESC) or Fault 
The indicators may also be in text form. Some manufacturers also include an intermittent beep while the system is active. Your dealer or authorized service center will be best equipped to address problems with the system.
But again, for the most part, these images appear 
The image with its squiggly or wavy lines behind a car, is unfortunately that of a car in a skid, which can be more than a little unnerving, particularly to drivers unfamiliar with the symbol’s meaning. It is seen whether the system is working to keep the vehicle in control and when the system is off, which the strike through line indicates. The addition of the wrench also indicates that the vehicle has detected a fault in the system. Again, the vehicle will operate normally, but without the advanced control system.
The last image to include is the triangle with an exclamation point inside. Some older vehicles that were first to offer stability control use this as a Slip Indicator or as a Fault Indicator. That is, it is seen when the system is doing its job and keeping the vehicle in control when a slip or skid is sensed, as was noted above.
These are Electric Power Steering (or Electronic or Electronically controlled) (EPS) Indicator 
As an electronic system, there is a chance it can be “reset”. Pull over as soon as possible and shut down the engine for a short period of time (on the order of 10-20 seconds) and restart the vehicle. If the light does not go out you will need to take the vehicle to your dealer or authorized repair facility as soon as possible.
Note that there is a 
Advanced stability control and traction control systems are the primary culprits, or more to the point, the electronics that they depend on. And they are the least likely to actually fail. These systems rely on signals from the electronics controlling the operation of the engine, transmission, 
Multiple lights rarely, if ever, mean multiple system faults. A fault in the engine (
These are the EV (Electric Vehicle), Hybrid and Plug-in Hybrid Battery Charge and Warning 
This version essentially points to a total system failure, unless it is seen in 
This version, shown in the vehicle’s information display, will be seen when the Mild Hybrid System is charging its battery. a Mild Hybrid System uses a 48-volt battery to assist the drive train, much lower capacity than the majority of hybrid systems. It appears as a double A battery with a lightning bolt inside.
These two will also to be seen in the vehicle’s information display. The first indicates the hybrid battery is charging. The other indicates that the battery is holding its charge. We surmise that this means that everything is functioning as expected.
This is a hybrid Charge Mode indicator. The light in the instrument cluster comes on when Charge Mode is switched on. While a hybrid charges its high-voltage battery automatically, with this system from Mazda, the vehicle can be told to charge the battery only and not using its power while the gasoline engine is running. Power is generated to a preset target amount, and when reached, power is generated to maintain it.
This is a High Voltage System Fault Indicator symbol for a Plug-in hybrid. An exclamation point is shown in a drawing of what looks like a D battery, which is meant to invoke the system’s battery. It could also be described as a box or a rectangle. It is likely that only the vehicle dealer can correct a problem with this system.
We found this one in the owner’s manual for two hybrids, and only one made clear that this is a hybrid battery malfunction. It was also found in an EV and also in fact indicates a main battery or system malfunction. Also, there will likely be an additional message on the instrument panel. Look for it and please check with your dealer or qualified service shop! Do not continue driving!
Finally, this version is used as a Battery Charge Indicator. It is shown in conjunction with a gauge that shows the actual charge level. It is seen in gray scale and does not indicate any trouble with the system. 
The image of a steaming hot cup of coffee is an Attention Assist Indicator 
And immediately after saying that color does not indicate a fault in the alert system, we find this symbol, in 
Another manufacturer adds the exclamation point, as seen in the symbol to the right, if the vehicle detects that it is being driven erratically. An audible tone is also added and likely a text message. The tone and message will be repeated if the driving pattern continues.
Finally, we have this version. Updated systems are able to detect a driver nodding off at the wheel! And so this symbol, which is a bell with three letter Zs, is shown and accompanied by a warning tone. This will continue until the driver turns it off. This part of the system is also limited by the ability to see the driver’s eyes. See more on this subject
Automotive Warning Lights: Scrap the Useless System
Is There Any Value in Current Dashboard Symbols?
Recent discussions in the automotive press (since deleted) have railed on the uselessness of the check engine light or called for an outright ban of the light and other automotive warning lights.
And they’re on to something. Lets face it. Scrap the useless system. The current and growing crop of automotive warning lights, including the check engine light, without the associated fault code or codes says nothing, to the driver in particular. However, in point of fact, the entire warning and indicator light system suffers from the very same problem:
What Should We Do Instead?
Of course, fault codes, gauges and meters are only of use to those with the ability to interpret them, which is the source of the ‘idiot light’ system in the first place. But the plain fact is that today’s vehicles have the capability to display not only an indicator light and fault code, but also an explanation of what is actually wrong in plain language AND what needs to be done at that moment:
Unfortunately, it is not likely that any manufacturer will step up and risk giving more detailed information to lay people out of liability fears. But the system as it exists now runs the real risk of needlessly frightening drivers with the circus of indicator and warning lights that can pop up at the drop of a gas cap. And sometimes two and three lights at a time.
Further, with 20, 30 and even more indicators on instrument panels today, is there not a risk of saturation? The 2017 Audi Q7 has over 100 lights or combinations of lights that may be shown!
When is enough enough? Every new system added to a vehicle is met with a new indicator and or acronym that, despite the best industry efforts, remain a mystery to the average driver. Seriously, most drivers need to get the kids to school and get themselves to their jobs. They are not car people and simply have too much on their plate as it is.
Even experienced service personnel have to search their memory banks to correctly identify the meaning of some of the more obscure acronyms (AFS does NOT start with ‘Automatic’… ). Should the industry expect more from drivers?
Seriously, before someone freaks out behind the wheel let’s stop throwing new lights at every new vehicle add-on and consider some alternatives. At the very least, new and existing lights should be accompanied by real and useful information.
And since drivers should NOT be reading while driving, how about having the vehicle talk to the driver by voice? With all the discussion surrounding driver distraction and the integration of Siri and other voice command systems into infotainment systems, we are not so far from this ‘Eyes Free’ solution. It’s just a little to the left, in the instrument panel…
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Remember that only proper service and repair procedures will ensure the safe and reliable operation of your car. In addition, proper safety procedures and precautions, such as the use of safety goggles, the right tools and the equipment should be followed at all times to eliminate the possibility of personal injury or improper service which could damage the vehicle or compromise its safety.
These posts are for information sharing purposes only, and should not be used in lieu of an OEM service manual or factory authorized service procedure. We are not in the auto repair business nor do we publish automotive service manuals. Nothing we include on these pages and posts has been reviewed, approved or authorized by any vehicle manufacturer.
Technology is always changing and what is current and accurate today may be literally out-of-date and inaccurate tomorrow. And when it comes to the current state of flux in the auto industry, nothing is more true.
The author has 25 years of automotive experience and has assembled the most extensive collection of symbols and warning lights anywhere (over 1,000!) and can help you open and start any keyless start car with a dead key fob battery. BA, St. Joseph’s College, ME: MS, Rensselaer Polytechnic Institute, NY