Error 39 · Err 39 · READ_LIGHT_SENSOR

VanMoof Error 39, explained.

Q: Is Err 39 the same as Error 39?

Yes. The matrix display abbreviates it as Err 39. The bike's internal logs and the Moofment app's diagnostics screen show it as Error 39.

Also shown as Err 39 on the matrix display · symbolic name READ_LIGHT_SENSOR

Code 39's symbolic name READ_LIGHT_SENSOR indicates an I²C read failure on the ambient light sensor. VanMoof.com does not publish a specific per-code description for this code.

What to try

VanMoof's official troubleshooting sequence is the same for every error code. Work through it in order:

Step 1 — Make sure the latest firmware is installed. Pair your bike with the original VanMoof app (see callout below) and let it apply any pending firmware updates.
Step 2 — Reset your bike. Hold the power button until the bike fully powers down, wait a few seconds, and turn it back on. A 10-second power-button hold is Step 2 of VanMoof's official troubleshooting sequence and often clears transient codes.
Step 3 — Perform a system restart. If the code persists after a reset, do a full system restart from the bike menu.
Still unresolved? Visit a VanMoof Partner for diagnosis and repair. VanMoof's documentation defers to authorised service partners for any error that survives the three universal steps above.

VanMoofer is an independent site. We don't ship parts or repair bikes — we just help you understand what your bike is telling you, using VanMoof's own canonical documentation as the source of truth.

Use the original VanMoof app for firmware updates

Step 1 of VanMoof's own troubleshooting sequence is making sure your bike has the latest firmware — and that update path only exists in the original VanMoof app, not Moofment. Pair the two: VanMoof app for firmware, Moofment for live Bluetooth diagnostics on the S3/X3.

S3 / X3 only

Read Error 39 (and every other code) live.

Moofment connects directly to your VanMoof S3 or X3 over Bluetooth and reads diagnostic codes the moment they appear — with plain-language explanations and no cloud accounts. If you're staring at Err 39 right now, this is the fastest way to confirm what the bike is reporting.

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Frequently asked

What does VanMoof Error 39 mean?

Error 39 has the symbolic name READ_LIGHT_SENSOR. Light sensor I²C. It belongs to the module & communication group of VanMoof's S3/X3 diagnostic codes.

Is Err 39 the same as Error 39?

Yes. The matrix display abbreviates it as Err 39. The bike's internal logs and the Moofment app's diagnostics screen show it as Error 39 / READ_LIGHT_SENSOR.

What should I try first when Error 39 appears?

Follow VanMoof's official 3-step troubleshooting sequence: install the latest firmware (via the original VanMoof app), reset your bike, then perform a system restart. If Error 39 still appears, visit a VanMoof Partner for diagnosis. See the 'What to try' section above for the full sequence and any code-specific hints VanMoof publishes.

Which VanMoof models show Error 39?

Error 39 belongs to the diagnostic code set used by the VanMoof Series 1 through Series 5 platform. In practice it appears most often on the S3 and X3, because that's where the matrix display surfaces it directly to the rider.

Can I read Error 39 from my phone?

Yes. The Moofment app reads live diagnostic codes over Bluetooth on the S3 and X3. Pair it with the original VanMoof app for firmware updates and you have full coverage.