This is the safety-critical one
Pre-Collision and AEB are what actually stop the car when you can't. A PCS fault means the system that prevents low-speed crashes is offline — don't drive on it longer than you have to.
Symptom: PCS / AEB warning
Pre-collision system fault, AEB disabled, or forward collision warning malfunction in Springfield, IL
If your dash is showing a Pre-Collision System fault, an AEB warning, or a message that automatic emergency braking is disabled or unavailable, the single most important active safety system in your vehicle has stopped protecting you. ADC recalibrates the camera and radar that PCS depends on, so the system can see the road again and step in if you can't.
Camera and radar, working as one
PCS isn't a single sensor — the windshield camera identifies the threat and the front radar measures closing speed. If either one is off-aim, the whole system disables itself rather than guess.
Brand-specific calibration, done right
Toyota PCS, Honda CMBS, Subaru EyeSight, Ford Pre-Collision Assist, Nissan AEB, Mercedes Pre-Safe, BMW Active Brake Assist — each has its own targets, distances, and pass criteria. We follow the OE procedure for yours.
What Pre-Collision actually does — and why a fault matters
Pre-Collision Systems are the layer of ADAS that goes beyond warnings and actually intervenes. Forward Collision Warning tells you a crash is coming; Automatic Emergency Braking applies the brakes for you when you don't react in time. Every major manufacturer markets its own version — Toyota Safety Sense PCS, Honda Sensing CMBS, Subaru EyeSight Pre-Collision Braking, Ford Co-Pilot360 Pre-Collision Assist, Nissan Intelligent Emergency Braking, Mercedes-Benz Pre-Safe, BMW Active Brake Assist — but the IIHS data behind them is the same: AEB-equipped vehicles see roughly 50% fewer rear-end crashes. In 2022 the IIHS and most OEMs standardized AEB as its own warning category on the dash, separate from the generic ADAS or check-engine telltale, so you know exactly which system has stepped offline. When that specific warning lights up, the computer has decided it can no longer trust the inputs feeding the collision-avoidance logic, and it shuts the system down rather than brake at the wrong moment. You still have your regular brakes — but the automatic safety net that catches distracted moments, sun glare, and short-following-distance mistakes is gone until it's recalibrated.
Why PCS commonly disables — it's almost always calibration
The good news: a Pre-Collision fault is rarely a dead sensor. PCS depends on two sensors aimed at the road ahead — the camera behind the windshield and the radar behind the grille or bumper emblem — and those mounts move. A windshield replacement repositions the camera. A front-end collision, even a light one, shifts the radar. A bumper repaint, a tow-hook install, a suspension alignment, a ride-height change from new tires or a lift, even hitting a deep pothole can knock the radar's aim outside its tolerance — and these systems measure in fractions of a degree. When the camera and radar disagree about where the car ahead is, the module flags a fault and disables PCS. The same misalignment is what causes phantom braking — the car slamming the brakes for a shadow, a manhole cover, or an overhead sign — because a mis-aimed radar reads stationary roadside objects as in-lane threats. And because modern vehicles share the front camera and radar across multiple features, when PCS drops out, Adaptive Cruise Control, Lane Keep Assist, and traffic-sign recognition usually go with it. Fixing one calibration brings the whole stack back.
What to do right now — don't drive long without PCS
Treat a Pre-Collision fault the way you'd treat a brake warning, because functionally that's what it is: your assisted braking is gone. Don't wait for it to clear itself — it won't. Clearing the code without recalibrating just hides the fault until the next ignition cycle, and it leaves the camera and radar pointed wherever the impact, glass shop, or pothole left them. Bring the car to ADC. We'll pull the live data from the camera and radar modules to confirm whether the issue is alignment, a blocked sensor, or a wiring fault; perform the OE static or dynamic calibration your vehicle requires in our climate-controlled bay; and hand you back documentation showing the system is within spec. Most PCS calibrations are a same-day visit. Until you can get in, increase your following distance, avoid highway use if you can, and don't rely on adaptive cruise — the cars around you don't know your safety system is offline, but you do.
Find your car's specific procedure.
Each manufacturer has its own ADAS suite, warning messages, and calibration steps. Pick yours for the brand-specific procedure.
Next step
Get a quoteGet your active safety system back online
PCS and AEB are the systems that step in when you can't. If yours is throwing a fault, book a calibration appointment with ADC in Springfield — most jobs are same-day.