Pedalwise
Troubleshooting

Tern e-bike troubleshooting: GSD, HSD and other Bosch equipped Terns

Where Tern keeps the Bosch manuals for its e-bikes, safe first checks, and how Tern's warranty, Tern Care, 7-Year Support and dealer service work.

Last edited Nov 8, 2026 by Pedalwise team Edit History Add a subpage

The Pedalwise team started this page from official manuals, support pages and repair videos. Fixed this yourself, or spotted something wrong? Help improve it.

Battery and electrical safety. Lithium-ion batteries can catch fire if they're damaged or charged wrong. Never open a battery pack, and stop using any battery that's swollen, hot, wet or smells burnt. Every edit to this page is checked by a second person before it goes live.

This page covers Tern e-bikes such as the GSD, HSD, NBD, Orox, Quick Haul and Vektron. Tern's support site hosts Bosch manuals for its e-bikes, for example the Bosch battery, charger, Purion display and drive unit manual for its BES2 models (Tern Bosch manual download), and its 7-Year Support program covers Bosch equipped Terns (Tern 7-Year Support). For the drive system itself, including error codes, use our Bosch troubleshooting page. This page covers what is specific to Tern.

Before you start

  • Find your exact model and generation, for example GSD S10 Gen 3 or HSD P5i Gen 2. Tern's support home links to a page for each family, such as GSD and HSD, and each family page lists every model and generation.
  • Download the Bosch manuals that match your bike from Tern's support pages. The Bosch manual set differs by model year and Bosch system.
  • Keep your proof of purchase handy. Tern asks for it for any warranty claim (Tern warranty).

Common problems and what to check

Bike won't turn on, no assist or motor cuts out

Battery won't charge or range has dropped

A battery that is swollen, cracked, leaking or smells burnt should not be charged or ridden. Take it to a Tern dealer or a pro.

Error code on the display

Tern bikes show Bosch codes. Look the code up on our Bosch page and e-bike error codes, and use the display manual from Tern's support site for your display.

Something feels wrong with the frame, rack or a part

Tern's warranty page says to stop using a product as soon as you suspect a defect and take it to an authorized Tern dealer for inspection (Tern warranty). That includes cargo racks and passenger parts on cargo models.

Adding accessories

Before you fit racks, seats or bags, run them through Tern's compatibility checker for your exact model.

Warranty and dealer service

  • Tern frames, forks and handlebar stems carry 5 years of cover, other parts 1 year. Register for Tern Care within 30 days of purchase and the frame, fork and stem cover goes to 10 years (Tern warranty).
  • Tern's warranty covers only Tern and BioLogic branded parts. Tern names Bosch as a third party brand whose parts are warrantied by their own maker, so motor and battery claims follow Bosch's terms (Tern warranty).
  • Claims usually go through an authorized Tern dealer, and you pay transport to and from the dealer. Commercial use such as rental or delivery is excluded.
  • Bought your Tern used? Tern has an online warranty transfer process.
  • 7-Year Support means Tern aims to supply replacement key parts for at least seven years on 2017 and newer Tern bikes. Tern stresses it is not a warranty and the parts are not free (Tern 7-Year Support).
  • Tern's dealer finder includes shops listed as service only.

Videos

Tern GSD Gen 2: Owner Briefing from Tern Bicycles: an owner's walk through of the second generation GSD.
How to Set Up Your Tern GSD Electric Bike from Fully Charged Electric Bikes: setting up a new GSD.
Tern GSD Cargo Bike Tips and Tricks from Arleigh, Bike Shop Girl: practical tips for living with a GSD.

Official help

When to get a pro

  • Bosch error codes that come back after a restart and a full charge.
  • Any battery or charger damage, and anything inside the motor, battery or wiring.
  • Suspected frame, fork, rack or stem defects, which Tern wants a dealer to inspect.
  • Brake bleeds, wheel builds and hub or motor work on loaded cargo bikes.

Never open the battery, charger or drive unit. A Tern dealer or a local shop can help. See when to call a pro.

Sources

Stuck after these checks? Find a shop near you.

Need a pro?

If these steps didn't fix it, find a shop near you in our partner network. For battery or wiring trouble, look for shops marked Battery and electrical.

Talk

Questions, things that worked for you, or something that looks wrong on this page.

Sign in to join the conversation.

CC BY-NC-SA 4.0Text by Pedalwise and contributors, shared under CC BY-NC-SA 4.0. Linked videos and manuals keep their own terms. How to reuse it