You take your car in for a routine repair — a windscreen replacement, a suspension job, maybe a wheel alignment — and you drive away thinking everything is fine. Then a warning light appears on your dashboard. It looks unfamiliar. A quick search tells you it’s related to your ADAS — your Advanced Driver Assistance Systems. Now what?

This is a situation we see regularly at MnF Motors. Drivers arrive confused and sometimes frustrated, having already paid another garage for a repair, only to be left with a dashboard warning that wasn’t there before. In the majority of cases, the issue is the same: the repairing garage did not carry out the necessary ADAS recalibration.

This article explains exactly what ADAS is, why recalibration matters, which repairs commonly trigger the need for it, and what can go wrong when it’s overlooked.

What Is ADAS and Why Does It Need Calibrating?

ADAS stands for Advanced Driver Assistance Systems. It is an umbrella term for the collection of electronic safety features now standard on the vast majority of modern vehicles. These include:

• Automatic Emergency Braking (AEB) — detects obstacles and brakes without driver input
• Lane Departure Warning (LDW) and Lane Keep Assist (LKA) — monitors lane markings and alerts or corrects the driver
• Adaptive Cruise Control (ACC) — maintains a set distance from the vehicle ahead
• Blind Spot Monitoring (BSM) — detects vehicles in adjacent lanes
• Rear Cross Traffic Alert — warns of approaching vehicles when reversing
• Traffic Sign Recognition — reads road signs and displays them to the driver

These systems rely on a network of cameras, radar sensors, ultrasonic sensors, and LiDAR units positioned around the vehicle. Every one of them is calibrated at the factory to a precise angle and position. If that position changes — even slightly — the system’s ability to accurately perceive the road environment is compromised. The vehicle’s ECU detects this misalignment and triggers a warning light.

Which Repairs Commonly Require ADAS Recalibration?

This is where many independent garages — particularly those without updated diagnostic equipment or manufacturer training — fall short. Recalibration is required far more often than most drivers (or some technicians) realise. Here are the most common triggers:

Windscreen Replacement

The forward-facing camera that powers AEB, lane-keep assist, and traffic sign recognition is typically mounted directly behind the windscreen. When the glass is removed and refitted, even minor variation in camera angle is enough to throw calibration out. Any reputable garage carrying out windscreen work on a camera-equipped vehicle should offer recalibration as part of the job — full stop.

Wheel Alignment and Suspension Work

Rear-facing radar sensors and blind spot monitors are calibrated against the vehicle’s axle geometry. If you’ve had suspension components replaced, springs changed, or a four-wheel alignment carried out, the angles that those sensors rely on may have shifted. It’s subtle, but modern ADAS systems are sensitive enough to detect it.

Bumper Removal or Replacement

Front and rear radar units for adaptive cruise control and parking sensors are often mounted in or behind bumper assemblies. Any removal — even for a minor paint repair — can disturb their position. If your ADAS light came on after bodywork, this is likely the cause.

Steering System Work

Lane-keep assist systems work in conjunction with the electric power steering. If the steering rack, column, or associated sensors are disturbed, a steering angle sensor reset and ADAS recalibration may both be necessary.

Battery Disconnection or Replacement

This one surprises many drivers. On certain vehicles — particularly newer European models — disconnecting the battery can cause ADAS control modules to lose their stored calibration data. A simple battery swap from a garage that doesn’t check for this can trigger a warning light.

What Are the Two Types of ADAS Calibration?

Understanding this helps you ask the right questions when speaking to a garage.

Static Calibration — What Does It Involve?

Static calibration is carried out in a controlled workshop environment. The vehicle is positioned on a level surface, specific targets or calibration boards are placed at precise distances and angles in front of (or around) the vehicle, and a diagnostic tool communicates with the ADAS control module to guide the sensor back into alignment. The workshop environment matters enormously — lighting, floor levelness, and space all affect accuracy. This is why it cannot simply be done in a car park or on the road.

Dynamic Calibration — What Does It Involve?

Dynamic calibration is performed while the vehicle is driven. A diagnostic tool is connected, and the technician drives the car along a road at a specified speed, often on a route with clear lane markings and defined road signs. The system “teaches” itself during the drive. Some vehicles require a combination of both static and dynamic calibration depending on which sensors are affected.

Can an ADAS Warning Light Cause an MOT Failure?

Yes — and this catches a lot of drivers off guard. Since the MOT standards were updated in May 2018, certain ADAS-related warning lights are now assessed during the test. Specifically, a permanently illuminated warning light for systems like AEB or lane departure warning can result in an MOT failure under the “driver’s view of the road” or “safety systems” categories.

If your car is due an MOT Testing and you have an ADAS warning light showing, do not leave it until test day. Get the fault diagnosed and rectified beforehand. Arriving with a known fault wastes your test fee and means your car is off the road for longer.

Is It Dangerous to Drive With an ADAS Warning Light On?

In most cases, when an ADAS fault is detected, the affected system defaults to “off” rather than operating incorrectly. So your AEB may not function, your lane-keep assist may be disabled. This means the car is usually still driveable — but you’ve lost safety features you may have come to rely on, and in some circumstances, you may not even realise they’re no longer working.

There are edge cases where a miscalibrated sensor rather than a fully disabled one could cause a system to react incorrectly — braking unexpectedly, or failing to warn of a lane departure when it should. These situations are less common but underscore why driving long-term with an unresolved ADAS fault is not advisable.

Why Do Some Garages Miss This?

Honest answer: ADAS recalibration requires specialist equipment, a suitable workspace, and ongoing technician training. Not every garage has invested in this capability. Some older facilities — particularly those that have been operating under the same model for many years — may have excellent mechanical skills but haven’t updated their equipment to handle modern vehicle electronics.

This isn’t always negligence. Sometimes it’s a knowledge gap. The garage performing your windscreen repair may genuinely not know that your specific vehicle requires camera recalibration, particularly if they don’t have access to vehicle-specific ADAS data. What matters is that when you pick up your car, you’re told what was done and what may still be required — not left to discover a warning light on the A406.

With over 25 years serving the Edmonton and North London community, the team at About MnF Motors has built its reputation on transparency. We will always tell you what a job involves, what it requires, and if we believe additional work is necessary for your safety — before we carry it out, not after.

What Should You Do If You Have an ADAS Light On After a Repair?

Here’s a practical step-by-step approach:

1. Don’t ignore it. Note when the light appeared and what work was done immediately beforehand.
2. Go back to the repairing garage first. If the work they carried out should have included recalibration, they should rectify this. Keep your paperwork.