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Tongsheng TSDZ2 error E04: Speed sensor error
Tongsheng TSDZ2 / TSDZ2B mid-drive with VLCD5, VLCD6 or XH18 displayFix at homeRide with caution
The controller gets no wheel speed signal. Speed shows 0, assist cuts out or stays limited. On the TSDZ2 this is usually the spoke magnet and the external sensor on the chainstay.
Likely causes
- Spoke magnet moved or too far from the sensor
- Speed sensor cable damaged or unplugged at the motor
- Sensor knocked out of position
- Water in the sensor connector
- Faulty sensor
How to fix Tongsheng TSDZ2 error E04
- Align the magnet with the sensor at a few millimetres gap
- Check the sensor cable and connector at the motor; dry and re-seat
- Spin the wheel with the display on; speed should register
- Replace the sensor and magnet
Go to a dealer if: Go to a shop if a new sensor still gives E04; the controller input may be faulty.
Warranty: TSDZ2 kits are usually covered 1 year by the reseller; motor and torque sensor faults are typical claims, water damage is not.
Typical cost: Sensor plus magnet EUR/USD 10-25; often free by realigning the magnet.
Warranty: TSDZ2 kits are usually covered 1 year by the reseller; motor and torque sensor faults are typical claims, water damage is not.
Typical cost: Sensor plus magnet EUR/USD 10-25; often free by realigning the magnet.
Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.
Frequently asked
Can I reset E04?
Fix the magnet gap and power cycle.
Can I keep riding?
Yes safely, with limited or no assist.
Warranty?
Rarely; a moved magnet is not a defect.
Related Tongsheng TSDZ2 codes
Not an official Tongsheng TSDZ2 document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.