Segway Ninebot Max G30P and G30LP: error 21 battery communication fault

Your Max G30P or G30LP shows 21 and won't ride normally. Error 21 on Segway Max scooters means the controller can't communicate with the battery management system (Levy Segway Max error codes). The dashboard shows the code and the Segway-Ninebot app shows the matching cause. The G30 manual has no code table (G30P user manual). Max scooters use the same code numbering as the E2 Pro (Segway E2 Pro self-test manual). The short answer: give it a long charge on the original charger, and if 21 stays, book a shop to check the battery connector, the battery and the controller.

Most likely cause

The controller reads the battery's state over a small data connection. When it gets no answer, it shows 21. Check the 4-pin battery communication connector, charge for several hours, and test with a known good controller and battery (Levy Segway Max error codes). On the E2 Pro, check and reseat the battery to controller cable, and replace the battery if the problem stays (Segway E2 Pro self-test manual).

Other causes to rule out

• A battery that ran very flat: charging for several hours covers this. Charge after each ride and avoid fully draining the battery (G30P user manual).
• Error 19, battery voltage abnormal: charge and watch the charger light.
• Error 39, battery temperature: keep the scooter between -10°C and 50°C and let it rest for over 30 minutes before checking again.
• Water: don't charge or use a battery that shows any trace of water.

How to confirm

1. Read the code and check the fault in the Segway-Ninebot app.
2. Bring the scooter indoors to room temperature. The G30LP's riding range is -10°C to 40°C (14°F to 104°F) (G30LP user manual).
3. Check that the charge port is dry and clean, then charge for several hours with the original charger. The light shows red while charging and green when full.
4. Power on. If 21 is gone, ride gently and recharge after each ride.
5. If 21 returns, stop. The next checks, the connector between battery and controller and a swap test, are inside the deck and belong to a shop.

Fix options

Long charge and rest (easy)

Levy's first step for you to try. It recovers a battery that has dropped too low to answer the controller. If the code returns after a full charge, move on.

Reseat the battery communication connector (pro)

Both Levy and Segway put this next. It sits beside the battery's power leads inside the deck, so have a shop do it.

Replace the battery or controller (pro)

A shop with a known good battery and controller can tell which part is at fault. Segway's store lists a control board assembly for the Max G30. A battery is a large share of the scooter's value, so read repair or replace before you approve one. If the scooter is under warranty, contact your dealer first.

Parts

• E-bike battery (Segway battery for the Max G30, shop fitted)
• Control board assembly for the Max G30 (shop fitted)

When to get a pro

Get help as soon as a full charge doesn't clear 21, and right away if the deck is hot, swollen, smells, or got wet. See battery won't charge, e-bike battery care and when to call a pro.

Sources

• Levy Segway Max error codes, fleets.levyelectric.com
• Segway E2 Pro self-test manual, support.segway.com
• G30LP user manual, support.segway.com
• G30P user manual, store.segway.com
• control board assembly for the Max G30, store.segway.com

Stuck after these checks? Find a shop near you.