Owner decision guide
Lane-keeping assist does not detect lane markings
Lane systems depend on visible markings, camera view, speed, steering input and enabled settings. Construction zones, worn lines, glare and a dirty windshield can prevent operation without a hardware failure. Before acting, check Lane-line quality and operating speed, Camera view through the windshield, Driver-assistance settings and warning messages. Record the exact condition, since temperature, speed, load and warning status all change the diagnosis. The sections below break this down further: conditions the system requires, road conditions that defeat it, settings that get changed and forgotten, when it is a real fault. This is rated routine risk: Arrange service for unexpected steering input, a persistent fault after windshield work, or a camera housing that is loose or damaged. 4 related questions are answered separately below. Reviewed under this site's evidence-first standard, sourced to NHTSA vehicle and recall guidance, with related driver assistance and infotainment guides linked at the end.
Evidence first
Lane-keeping systems read lane markings with a forward camera. When they do nothing, the most common reason is that the camera cannot see markings clearly enough to act on them, not that the system has failed.
Many systems also have speed thresholds and activation conditions that are easy to forget.
Conditions the system requires
Most implementations need all of these before they will intervene.
- Clearly visible lane markings on both sides, or at least one depending on the system
- A speed above a minimum threshold, commonly around highway speeds
- The turn signal off: signalling intentionally suppresses intervention
- Hands detected on the wheel on systems that monitor this
- The feature switched on in vehicle settings
Road conditions that defeat it
Faded, worn, snow-covered or temporarily re-striped markings are invisible to the camera. Construction zones with conflicting old and new lines are a particular problem.
Heavy rain, standing water reflecting markings, and low sun directly into the camera all reduce recognition. Sharp curves beyond the system's steering authority will also produce no intervention.
Settings that get changed and forgotten
Many vehicles offer several modes, warning only, gentle steering assist, or full centring, and some reset to a default at each start.
Check the driver-assistance menu before assuming a fault. On some vehicles the setting also lives in a driver profile that changes with the key used.
When it is a real fault
A system that reports a fault message, or that stopped working after front-end or windshield work, needs attention instead of adjustment.
Camera calibration after windshield replacement is the single most common overlooked cause of a system that silently stopped intervening.
What to check before acting
| # | Check | Why it matters |
|---|---|---|
| 01 | Lane-line quality and operating speed | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
| 02 | Camera view through the windshield | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
| 03 | Driver-assistance settings and warning messages | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Safe sequence
What to do next
| Step | Action |
|---|---|
| 1 | Confirm the system is enabled |
| 2 | Clean the exterior windshield in the camera area |
| 3 | Test on a clearly marked road and scan/calibrate if it still fails |
- 1
Confirm the system is enabled
- 2
Clean the exterior windshield in the camera area
- 3
Test on a clearly marked road and scan/calibrate if it still fails
Avoid making it worse
What not to do
- Do not rely on the system to keep the vehicle in lane
- Do not mount objects in the camera field
Arrange service for unexpected steering input, a persistent fault after windshield work, or a camera housing that is loose or damaged.
Source and scope
Common questions
Why does lane keeping do nothing on my usual road?
Most systems need clear lane markings on both sides and a minimum speed. Faded markings, construction re-striping, or a speed below the threshold all prevent intervention.
Does using the turn signal turn it off?
Yes, deliberately. Signalling tells the system the lane change is intentional, so it suppresses the correction.
Do I need calibration after windshield replacement?
Usually yes. The camera is aimed relative to the vehicle, and replacing the glass moves it. A system that stopped working after glass work is a strong indicator.
Can I rely on it to steer for me?
No. Lane keeping is an assistance feature that requires a driver steering, watching and ready to take full control at all times.