Jasion Controller and Display Settings: User’s Guide
The Jasion display and controller work together to let you control pedal assist (levels 0–5), toggle the headlight, scroll through trip/odometer/speed readouts, and enter a hidden settings menu to adjust wheel size, speed limit, battery voltage, and more. This guide walks through each function in order, with practical checks to avoid common mistakes. Getting these settings right directly affects speed accuracy, range, and compliance with local e-bike laws.
Before You Start
Make sure your Jasion e‑bike is fully charged and the battery is securely connected. If the display stays dark after power‑on, you’ll need to troubleshoot the battery connector first (see the branch point below). You’ll also want a small Phillips screwdriver if you plan to swap the display for a replacement.
Have your bike’s original spec sheet handy—especially the wheel diameter (e.g., 26 inches) and battery voltage (36V or 48V). Incorrect values in the settings menu can cause speed inaccuracies or even trigger error codes. For example, if you set the wheel diameter smaller than actual, your speedometer will read faster than your true ground speed, which could make you think you’re exceeding the legal limit when you aren’t—or vice versa. Also note the protocol number printed on the back of your display (often “KT” or “No. 2”) if you ever need a replacement.
Basic Controls: Pedal Assist and Display Modes
Two buttons control everyday riding: the Mode button (usually labeled M) and the Up/Down rocker. These are weather-sealed but can become sticky if moisture gets under the rubber pad. Drying the bike indoors usually restores normal feel.
Adjusting Pedal Assist Level
Press Up to increase assist (1–5) or Down to decrease. Level 0 delivers no motor power—you’re pedaling cargo alone. Level 5 gives maximum push, best for steep hills or heavy loads. The assist number updates instantly on the LCD. If the motor feels jerky at level 1, your PAS sensor type (P05) might be set wrong (see Advanced Settings).
Cycling Display Readouts
Tap the Mode button briefly to switch between:
| Readout | What It Shows |
|---|---|
| ODO | Total miles the bike has ever traveled |
| TRIP | Miles since last reset |
| MAX | Highest speed recorded this ride |
| VOL | Battery voltage (only on some models) |
To reset the trip odometer, hold Mode for about 3 seconds while on the TRIP screen. The number will zero out. This is useful for tracking a single commute or ride length.
Turning the Headlight On/Off
Hold the Up button for 2 seconds. A headlight icon appears on the display when active. If the icon shows but the light doesn’t turn on, you may have a wiring issue—check the thin cable running from the display to the headlight for cuts or a loose connector. The headlight draws minimal current, so a burned-out LED bulb is rare but possible after a crash or water ingress.
Advanced Settings Menu
Hold both Mode and Up simultaneously for about 5 seconds to enter the hidden menu. Use Mode to select a parameter (P01, P02, etc.), then Up/Down to change the value. Press Mode again to save and move to the next. Exit by holding Mode for 2 seconds.
Key Parameters (with Rider Impact)
| Parameter | What It Does | Why It Matters |
|---|---|---|
| P01 – Screen brightness | 1 (dim) to 3 (bright) | Set to 3 for daylight visibility; lower setting saves minimal battery. On bright days the dim setting is nearly unreadable. |
| P02 – Units | 0 = mph, 1 = km/h | Choose mph for US roads. If you accidentally set km/h, your speed readout will show numbers about 60% lower than actual (e.g., 12 mph reads as 20 km/h). |
| P03 – Battery voltage | Must match your pack (36V or 48V) | Wrong voltage can cause controller damage or erratic power delivery. A 48V battery set to 36V will trigger an overvoltage error; a 36V set to 48V may run weakly or shut down early. |
| P04 – Sleep timer | Minutes before display turns off | 5–10 minutes is fine; doesn’t affect riding. A very short timer (1 minute) can be annoying if you stop frequently. |
| P05 – PAS sensor type | 0 = speed sensor, 1 = cadence sensor | Most Jasion models use cadence (1) – if you change this, pedal‑assist response may feel jerky or delayed. |
Only change if you’ve replaced the bottom bracket sensor. |
| P06 – Wheel size (inches) | 20, 24, 26, 27.5, 700c, etc. | Critical for speed accuracy – a 26″ wheel set as 20″ will read 30% too fast. Check the sidewall of your tire (e.g., 26×2.0) and match the diameter, not the width. |
| P07 – Speed limit (km/h) | Maximum motor cutoff speed | Class 2 limit = 32 km/h (20 mph). Exceeding it may violate local laws. If you set a higher number, the motor will keep pushing past 20 mph, making your bike Class 3 in some jurisdictions. |
| P08 – Throttle mode | 0 = throttle off, 1 = throttle on | Set to 1 if your Jasion has a thumb throttle. If you set it to 0, the throttle will be dead—common after a reset. |
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Resetting to Factory Defaults
There is no single “factory reset” button. To revert all parameters, you must manually enter each value you recorded before changing them. If you didn’t record them, contact Jasion support for your model’s baseline settings (typically P03=36V, P06=26”, P07=32km/h, P08=1, P05=1 for most Jasion e-bikes). Alternatively, you can try holding Mode and Down together for 10 seconds—on some firmware versions this restores defaults, but it’s not guaranteed.
What to Do If the Display Won’t Turn On (Branch Point)
Symptom: You press the power button (or the Mode button) and the screen stays black.
First check: Is the battery seated firmly? Open the battery compartment and push the connector together until it clicks. If the display lights up, you’re good.
If it still stays dark: Check the battery voltage with a multimeter. A fully charged 36V pack reads about 42V; a 48V pack reads about 54V. Below that, the battery may be deeply discharged or faulty. Try charging for at least 4 hours. If the charger shows green immediately, the battery may be at 100% but the BMS is in protection mode—disconnect and reconnect to wake it.
If voltage is normal but display remains off: The display or its cable may be damaged. Inspect the thin 5‑pin wire from the display to the controller for cuts or pinches. A broken pin inside the connector can also cause this. In that case, you’ll need a replacement display (see compatible options below). Also check the controller end—sometimes the connector gets pulled partially out during a battery removal.
Troubleshooting Common Issues
| Problem | Likely Cause | Safer Next Move |
|---|---|---|
| Buttons unresponsive | Moisture or debris under rubber pad | Wipe edges with dry cloth; let bike sit indoors for a day. If persists, replace display. |
| Headlight icon on but light off | Broken wire at headlight or connector | Inspect cable from display to headlight. If wire is intact, the LED may be burned out – replace the light unit. |
| Error code E01 or E05 | Communication fault between display and controller | Disconnect battery for 5 minutes to reset. If error returns, check all cable connections. Contact Jasion support for controller replacement. |
| Speed reading erratic after changing wheel size | P06 set to wrong diameter | Re‑enter settings and verify wheel size (e.g., 26″ = 66 cm). |
Test by rolling the bike one revolution and measuring actual vs. displayed distance. |
| Battery bars drop suddenly under load | Loose battery connector or weak cell group | Tighten connector; if problem persists, battery may need replacement. |
| Motor stops at 20 mph even when P07 is higher | Some controllers have a hard cap at 20 mph | Check your controller model—Jasion uses both programmable and fixed‑limit controllers. If fixed, no software setting will override it. |
| Display shows “Err04” or flashing battery icon | Throttle was engaged while powering on | Release throttle, turn off, wait 10 seconds, then power on again. |
Compatible Replacement Displays
If your original Jasion display fails, the following aftermarket LCD units work with many Jasion controllers. Always verify the pinout (5‑pin is common) and protocol (No. 2 or KT) before buying. The protocol number is often printed on the back of your current display; if you can’t read it, contact Jasion support with your bike model and year.
| Product | Brand | Notes |
|---|---|---|
| Bike Display LCD 5 Pin M5 Control Panel Bike Screen 24V 36V 48V 60V Universal | GEERYZHE | Universal 5‑pin, No. 2 protocol; fits 22.2/31.8mm handlebars |
| E Bike Display Ebike Screen GD01 Waterproof 5 Pin | Jumplushion | Waterproof, works with 24V/36V/48V systems |
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Use the steps above to adjust your Jasion controller and display with confidence. Small changes—like setting the correct wheel diameter or battery voltage—directly improve speed accuracy and prevent unexpected errors. If you ever get stuck after a setting change, re‑enter the menu and revert each parameter to its factory value (record them before changing). That’s the quickest way back to a working ride. For persistent hardware issues, Jasion’s customer support can confirm your display protocol and recommend the correct replacement part.
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Ryan Williams has spent over 8 years testing, repairing, and writing about electric bikes. He has personally ridden and reviewed 150+ e-bike models from brands like Lectric, Aventon, Rad Power, Super73, and dozens more.
Before founding EBIKE Delight, Ryan worked as a bicycle mechanic for 5 years at independent bike shops across California, where he specialized in e-bike conversions and electrical system diagnostics. He holds a Certificate in Electric Vehicle Technology from the Light Electric Vehicle Association (LEVA).
Ryan’s work has been cited by Electric Bike Report, Electrek, and BikeRumor. When he is not testing the latest e-bike on California backroads, he is in his workshop tearing down batteries and controllers to understand what makes them tick — and what makes them fail.
Areas of Expertise
E-bike performance testing and real-world range verificationBattery diagnostics, charging best practices, and safetyBrand comparisons: Lectric, Aventon, Rad Power, Super73, and moreError code troubleshooting across major e-bike systemsE-bike laws, registration, and compliance by state
Ryan believes every rider deserves honest, hands-on information — not marketing hype.