The new mandatory safety systems: what appeared in cars and how it behaves

A few years ago driver assistance systems marked out an expensive car. Now they come as standard even on budget models — not because manufacturers got generous, but because a set of them became mandatory for new vehicles in a number of markets.

For an owner that means two things: the car is safer, and it has acquired a new class of behaviour that is easily mistaken for a fault.

What exactly appeared

Speed limit assist

Reads signs with a camera and navigation data, compares them with your speed, and warns when you exceed it — by sound, pedal vibration, or a change in pedal effort.

Why it irritates: the camera sees a sign on a slip road or a parallel street and treats it as yours. The most frequent false triggers are at junctions and near roadworks.

What to do: on most cars the system can be switched off in settings, but it re-enables at every start. That is a requirement, not a bug.

Driver attention monitoring

Assesses fatigue from steering behaviour: micro-corrections, time on the road, time of day. Some cars add a camera watching where you look.

Why it irritates: it suggests a coffee after fifteen minutes if the road is twisty and you are working the wheel.

Lane keeping

The camera sees the markings and steers back when you approach them without indicating.

Why it irritates most: on roads with worn markings, after resurfacing with old lines still visible, or in ruts. The system pulls the wheel where you did not intend to go.

Important: if the car feels like it is “resisting”, that is the system. Not the suspension and not the alignment.

Automatic emergency braking

A bumper radar plus a camera. It brakes if it sees an obstacle and judges the driver is not reacting.

The most important item on this list and simultaneously the most sensitive to sensor condition.

Tyre pressure monitoring

Long since familiar, covered in its own article.

Event data recorder and emergency call

Covered separately — the black box and the emergency call system.

The main practical problem: calibration

Here is what to know before your first workshop visit.

The bumper radar and windscreen camera must be aimed to within a fraction of a degree. Any of the following requires recalibration:

• Windscreen replacement.
• Bumper repair or replacement.
• Front-end body repair.
• Glass replacement after a chip.
• Wheel alignment.
• Ride height changes — springs, different tyre sizes.

The dangerous scenario is not “the system does not work” but “the system works and is wrong”: braking for nothing, or failing to see an obstacle. The verification procedure is in the ADAS calibration guide.

Practical takeaway: after a windscreen replacement, ask whether the camera was calibrated. It is a separate operation, and cheap workshops frequently skip it.

What diagnostics can see

Expectations here deserve calibrating alongside the camera.

Available with a consumer adapter:

• B and C series codes from the relevant modules.
• U-series network codes if an assistance module stops answering — U0100, U0121; mechanics in its own guide.
• The module roll call — whether the camera and radar modules answer.
• Wheel sensor codes, on which half these systems depend: C0035–C0050.
• The speed signal — P0500; without it most assistance systems disable themselves, see the speed sensor guide.

Not available: calibration status, camera data, threshold settings. Those are manufacturer requests — the mechanics of that limit are in the supported PIDs guide.

Why systems disable themselves

Causes that look like failures and are not:

• A dirty camera or radar. Snow, ice, caked mud, a sticker on the glass in the camera’s field.
• Heavy rain or fog.
• Worn markings — lane keeping simply has nothing to work with.
• Voltage sag. Assistance modules draw significant current and switch off first on a weak battery. The standard check: 12.4–12.7 V overnight.
• Module overheating after long driving in hot weather.

A “system temporarily unavailable” message in these cases is correct behaviour, not a fault.

What this means when buying

A new layer of checks:

1. The module roll call — do the camera and radar modules answer.
2. B, C, and U series codes — not just P.
3. Signs of a windscreen replacement — and the question of whether the camera was calibrated.
4. Signs of front bumper repair — the radar lives there.
5. Whether systems have been permanently disabled in settings — sometimes that is how a fault gets hidden.

The general protocol is in the used car guide, and post-crash specifics in the rebuilt salvage guide.

In short

• The assistance set in new cars is now standard rather than optional.
• Most “odd behaviour” in the first weeks is the systems working, not a fault.
• Windscreen and bumper work require calibration, and it frequently gets skipped.
• The danger is not a dead system but a system that works and is wrong.
• Calibration status is not readable with a consumer adapter — that needs manufacturer requests.

Download the app — B, C, and U series codes, the module roll call, and voltage are read with an ELM327 adapter over Bluetooth SPP on Android.