- Electric mobility
- Electric bicycle
Er33
Yamaha Er33 on electric bike: torque sensor voltage fault
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Code Er33 (error 33 in Yamaha's fault table) indicates abnormal no-load voltage at the torque sensor; stop safely, take both feet off the pedals, and restart Display A waiting two seconds. If repeated detections lock the error on, visit an authorised Yamaha dealer.
Safety first
Stop and check this first
- When stopped, always apply both front and rear brakes and keep both feet on the ground; resting a foot on a pedal while stationary can unintentionally engage power assist or trigger a startup fault.
- Never disassemble the Drive Unit, strike the crank axle with a hammer, or tamper with sensors or speed limiters; any internal drive repair must be carried out by an authorised Yamaha dealer.
Safe checks you can perform
- Power-cycle Display A with both feet off the pedals and wait two seconds
- Check that the cranks and chain are free from external tension
- Inspect the crank arms and axle area for signs of impact
Leave these tasks to a qualified professional
- Do not attempt this professional task: Dealer torque sensor reference voltage adjustment and fault reset
- Do not attempt this professional task: Authorised replacement of the torque sensor assembly
- Do not attempt this professional task: Replacement of the controller assembly or complete Drive Unit assembly
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Dealer torque sensor reference voltage adjustment and fault reset
What they doAn authorised Yamaha dealer connects the factory diagnostic tool to perform the torque sensor reference voltage adjustment and clear the latched error.
They must show youthe diagnostic readout showing no-load torque voltage before and after the reference adjustment.
In writingthe completed torque sensor reference voltage adjustment and error 33 clearance on your invoice.
Authorised replacement of the torque sensor assembly
What they doIf reference voltage adjustment cannot bring the unloaded signal within specification, the workshop replaces the internal torque sensor assembly.
They must show youtest data confirming the sensor failed reference calibration along with the replaced torque sensor assembly.
In writingthe part number of the replacement torque sensor assembly and confirmation of post-repair road testing.
Replacement of the controller assembly or complete Drive Unit assembly
What they doIf error 33 remains after torque sensor calibration and servicing, the dealer replaces the controller assembly (internal circuit board) or the Drive Unit assembly.
They must show youworkshop verification that reference adjustment and sensor checks were completed before replacing the controller or drive unit.
In writingthe serial or part number of the new controller or Drive Unit assembly and warranty coverage.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Power-cycle Display A with both feet off the pedals and wait two seconds
- Who:
- you.
- How:
- stop the bicycle completely, remove both feet from the pedals, turn Display A off, wait a few seconds, turn it back on, and wait about two seconds before pedalling.
- Result that matters:
- allowing the power-on diagnostic routine to read an unloaded zero-torque baseline.
- If the Er and 33 display clears:
- wait two full seconds after startup before riding away.
- If error 33 stays on screen:
- note that when the system detects this error several times, it locks and cannot clear by power cycling alone.
- Evidence to keep:
- note recording whether a foot was on the pedal at startup and whether cycling power cleared code 33.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A) · Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
Check that the cranks and chain are free from external tension
- Who:
- you.
- How:
- with power switched off on level ground, verify that nothing is resting against the pedals and that the chain is not jammed or pulling on the chainring.
- Result that matters:
- ruling out mechanical drivetrain binding that could preload the torque sensor during startup.
- If the cranks and chain sit completely free:
- proceed to inspect the crank arms for impact damage.
- If you feel crunching, binding, or play in the crank axle:
- stop riding and have a bicycle dealer inspect the drive unit.
- Evidence to keep:
- photo of the chainring and crank area clear of debris or chain jams.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A) · Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
Inspect the crank arms and axle area for signs of impact
- Who:
- you.
- How:
- visually check both crank arms for bends or rock strikes that could transfer mechanical stress directly into the crank axle inside the drive unit.
- Result that matters:
- identifying physical impact damage, since Yamaha notes the crank axle connects directly to the inside of the Drive Unit.
- If cranks look straight and undamaged but Er33 persists:
- book a reference voltage adjustment at your Yamaha dealer.
- If a crank arm is bent or the axle feels loose:
- do not ride the bicycle and take it to an authorised dealer.
- Evidence to keep:
- photo of both crank arms and the drive unit spindle area.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A) · Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Electric mobility
- Brand
- Yamaha
- Product type
- Electric bicycle
Known code variants
- código 33 sensor de par Yamaha
- error 33 bicicleta eléctrica Yamaha
- Yamaha e-bike error 33
- Yamaha Er 33
- Yamaha Er33
- Yamaha Error 33
- Yamaha PWseries S2 error 33
- Yamaha PWseries ST Er33
- Yamaha torque sensor code 33
What it means
In Yamaha's official Owner's Manuals for e-bikes equipped with Display A (Booster Easy X3W-F819D-E0 with the PWseries S2 drive unit and CrossCore RC X2X-F8199-E2 with the PWseries ST drive unit), error code 33 shown with the alternating Er display means the torque sensor has detected an abnormal no-load voltage. The manual says that if you rested a foot on a pedal at power-on you should remove your feet, switch on again and wait about two seconds before riding. Other Yamaha drive generations or displays may differ in behaviour. A code alone never proves a part is faulty: foot pressure during power-on produces the same reading as a drifted sensor.
Warnings and stop conditions
- Higheditorial warning
When stopped, always apply both front and rear brakes and keep both feet on the ground; resting a foot on a pedal while stationary can unintentionally engage power assist or trigger a startup fault.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A) · Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
- Mediumeditorial warning
Never disassemble the Drive Unit, strike the crank axle with a hammer, or tamper with sensors or speed limiters; any internal drive repair must be carried out by an authorised Yamaha dealer.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A) · Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
Symptoms and causes
Probable causes · in order
- Turning on the Display Unit with a foot resting on the pedalsCommon
Placing weight on the pedals while pressing the power switch or pedalling before waiting roughly two seconds prevents the diagnostic check from reading a zero-load baseline.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A) · Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
- Drifted torque sensor reference voltage or mechanical drivetrain preloadPossible
An offset in the torque sensor zero-point calibration or mechanical binding on the crank axle keeps the unloaded voltage outside Yamaha's expected window.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A)
- Internal fault in the torque sensor assembly or drive unit controllerLess common
When error 33 triggers repeatedly with unloaded cranks and latches so power cycling no longer clears it, the torque sensor assembly or controller board may have failed.
Evidence: Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A)
Virtual technician
Does Er33 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Yamaha Booster Easy Manual del Propietario (X3W-F819D-S0, PWseries S2 y Display A)
Yamaha Motor Europe · 2026 · manual
- 2
Yamaha Booster Easy Owner's Manual (X3W-F819D-E0, PWseries S2 and Display A)
Yamaha Motor Europe · 2026 · manual
- 3
Yamaha Wabash RT Manual del Propietario (X2X-F8199-S1, PWseries ST y Display A)
Yamaha Motor Europe · 2026 · manual
- 4
Yamaha CrossCore RC Owner's Manual (X2X-F8199-E2, PWseries ST and Display A)
Yamaha Motor Europe · 2026 · manual
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