Error 26 is one of the less common codes on a Bafang display, and the short label in most code tables does not tell you much. Here is what Bafang's own manuals say it points to, and what to check before you order anything.
What the manuals say
The 500C and 860C display manuals list code 26 as "torque sensor error-speed." One 860C manual adds a single line of advice for it: contact the supplier. Code 25, right next to it, is the torque side of the same sensor. The rest of the table is in our overview of Bafang display error codes.
A torque sensor reports two things
Bafang's dealer manual for its bottom bracket torque sensor (the SR PA2XX series) names the part a "torque and speed sensor." It sits in the bottom bracket shell with the crank spindle running through it, and it sends the controller two separate signals:
- Torque: how hard you push on the pedals, sent as a voltage. The spec sheet lists 0.75 to 3.2 V across a 0 to 80 N·m range.
- Speed: a stream of pulses as the spindle turns (the spec sheet lists 32 speed pulses), which lets the controller tell how fast the cranks are turning.
Code 25 points at the first signal and code 26 at the second. So a 26 is about the pedal sensor's rotation signal, not road speed.
Do not mix it up with 21
On the same displays, code 21 is a speed sensor error, and it refers to a different part: the bike's speed sensor, not the pedal sensor. The advice differs too. That 860C manual says to check the sensor for 21 and to contact the supplier for 26.
Numbers also change meaning between brands; on many other systems 21 and 25 mean something else, as covered in the 21 through 30 code family. And not every Bafang display uses this table: the DPC18 code list, for example, has no 25 or 26. If you are not sure what you have, identify your display model first.
What to check first
Turn the system off and remove the battery before you unplug anything, then work through these in order. None needs special tools.
1. Note when the code appears. Does it show at power-on before the cranks move, or only once you start pedaling? Whoever looks at the bike next will ask.
2. Inspect the sensor plug. The manual shows a six-wire connector: 5 V power, ground, two data lines (CAN H and CAN L), and two wires labeled speed signal 1 and speed signal 2. With two of the six wires dedicated to the speed side, a bent or pushed-back pin, moisture, or green corrosion at this plug is the first thing worth ruling out. Unplug it, look into both halves with a light, let any moisture dry, and reseat it firmly, the same way as for water in a motor connector.
3. Follow the cable out of the bottom bracket. During installation the sensor cable is fed through the bottom bracket shell and out of a hole fitted with a rubber grommet. The manual warns that the cable must not be scratched on the way in, and that fitting and removal must follow the set procedure to avoid a broken wire. Where it leaves the frame, a missing grommet, a pinch point, or rubbed-through insulation is a real lead.
4. Think about what changed. The manual's cautions are specific: store the bike away from strong magnetic objects, keep magnetic materials off the shaft, do not knock the sensor during transport or installation, and avoid riding through water. If the code showed up right after bottom bracket work, a drop, a deep puddle, or a magnetic tool left near the spindle, mention it.
5. Check that the cranks turn freely. The manual's own installation check is simple: set a crank horizontal with its pedal on, and it should droop freely. If the spindle binds after recent work, have the installation looked at before chasing electronics.
When it goes beyond a home fix
If the plug and cable look clean and the code keeps coming back, you have reached the manual's next step: the supplier. The sensor talks to the controller over a data bus, and reading its live values takes the manufacturer's service tool, so the bike's dealer or brand is the right next stop.
What will not help is swapping in a generic cadence sensor. A cadence sensor only reports that the pedals are turning, not how hard you push, so it is not a drop-in replacement for a torque sensor, and we do not stock a torque sensor replacement. Our cadence sensor troubleshooting guide applies only to bikes built with one.
Before you get in touch, photograph the display showing the code, the sensor plug, and where the cable exits the frame. Like the photos we ask for to confirm a part fits, it saves a round of back-and-forth.