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[Robot kits](https://robotsforthat.com/robot-kits/) / [ELEGOO Smart Robot Car V4 troubleshooting](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/) / **It misses the line**

Updated 2026-10-27

# ELEGOO Smart Robot Car V4: it misses the line

Researched by [Riley Hart](https://robotsforthat.com/author/riley-hart/) · based on ELEGOO Smart Robot Car V4 build guide and docs · we may earn a commission

Short answer The line sensor needs contrast and the right threshold. Start with this: Use black tape on a light floor.

## Why it happens

The line sensor needs contrast and the right threshold.

## How to fix it

- Use black tape on a light floor.
- Press 4 or 6 on the remote to tune the sensor, 5 to reset.
- Check the 5 wire cable is in at both ends.

## Check the step it comes from

Step 29 of 29

### Let it drive itself

In the app, try Obstacle Avoidance: put it on the floor and watch it turn away from walls. Then try Line Tracking on a black tape line.

**Tip:** If it misses the line, use keys 4, 5 and 6 on the remote to tune the sensor.

**Check:** It turns away from walls on its own.

**Common mistake:** Testing line tracking on a dark floor. Use black tape on a light floor.

[See this step in the full build guide](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-build-guide/#step-29)

Still stuck?

## Show the AI coach a photo

Open step 29 in the free build tool, tap Stuck and take a photo. The coach checks it against that exact step and tells you what to change. 3 free questions per kit.

[Open step 29 →](https://robotsforthat.com/lab/build/elegoo-car-v4/steps/#step-29)

## Other ELEGOO V4 problems

[The app will not connect The board switch is on upload, or the phone left the car's Wi-Fi.](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/#app-wont-connect)[No camera picture The camera cable is loose or the camera board is upside down.](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/#no-video)[The car spins in circles or drives backward Motor plugs are in the wrong ports.](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/#spins)[The remote does nothing The plastic tab is still in the remote, or the battery is low.](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/#remote)[Nothing turns on The battery is flat or switched off.](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/#no-power)[A wheel wobbles or falls off The wheel went on at an angle or the screw is missing.](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/#wheel-wobble)

[All 8 ELEGOO V4 problems and fixes](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-troubleshooting/) · [The full build guide](https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-build-guide/)

**ELEGOO Smart Robot Car Kit V4.0** About $66 to $80. Every part and tool in one box.

[Check price on Amazon](https://www.amazon.com/dp/B07KPZ8RSZ?tag=robotsforthat-20)

## Sources

- [ELEGOO Smart Robot Car V4.0 assembly tutorial (PDF)](https://drive.google.com/drive/folders/1hACczXN-CzxTFHsO3yrLW7QJ1HhHiZJJ)
- [ELEGOO Smart Robot Car V4.0 downloads](https://www.elegoo.com/blogs/arduino-projects/elegoo-smart-robot-car-kit-v4-0-tutorial)

Drawings by robotsforthat. ELEGOO Smart Robot Car V4 is a trademark of ELEGOO. We are not affiliated with ELEGOO.

HTML version: https://robotsforthat.com/robot-kits/elegoo-smart-robot-car-v4-line/