Collision Warning System and Malfunction Indicators Full Story

Pre_collision_system_indicatorCollision Mitigation Brake System IndicatorPCS stands for Pre Collision, or Crash, System. FCW stands for Forward Collision Warning System. Another is CMBS or Collision Mitigation Brake System. Yet Forward Collision Warning OffPre-safe Seat Beltanother 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.

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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.

Note that some 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!

Sensor Blocked Indicator SymbolA 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.

Collision WarningForward Collision Warning OffAuto Braking Indicator SymbolThese 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 above right, which adds the exclamation point in the triangle alert and an arrow, illuminates when the brakes are applied automatically, which would be obvious if it occurred!

Forward Collision System Fault IndicatorIf either of above 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.

Front End Collision Warning IndicatorThis one to the left is a Front-end Collision Warning indicator, although the symbol is that of the back-end of a car. The manufacturer uses the same symbol for both a warning that the system has a problem or if a collision is imminent. We’ve shown it in red, which is used when a potential collision is detected. It will flash red as the condition worsens and/or when the relative speed between the two vehicles is great.

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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