Pedal Assist System (PAS) Troubleshooting Guide

All ebikes by Rad Power Bikes are equipped with a pedal assist system (PAS) that puts the power of the motor right in your pedal stroke.

Over time and with normal use, the PAS sensor connection may become loose or the magnet ring may shift too far from the PAS sensor to deliver a strong signal. If the throttle works but the PAS feature doesn't work or works intermittently, then it's likely that the rest of the powertrain is still working and the PAS needs some troubleshooting.

In the unlikely event the PAS becomes non-functional, follow the steps below to troubleshoot the issue.

Caution.png If you are not confident in your ability to successfully and safely perform all steps, we recommend having the work performed or checked by a local, certified, and reputable bike mechanic.

Note: These troubleshooting steps are for models that have a magnet ring and a PAS sensor and a throttle that works. For help with troubleshooting issues with the integrated PAS on a RadRunner, RadRunner Plus, or RadMission, or for help troubleshooting issues with a throttle that doesn't work, contact us for help.

Tools needed:

  • A camera
  • Clean paper towel or shop towel
  • Flat side cutters
  • Replacement zip ties
  1. Get the bike ready for maintenance. Turn off the bike, remove the battery, and press and hold MODE to discharge remaining power.
  2. Prepare your camera to record a video of working through the troubleshooting steps below. The video will help our Product Support team troubleshoot your issue if further troubleshooting is required.
  3. Locate the magnet ring and PAS sensor behind the right crank.

    PAS_sensor.PNG
  4. Check that the magnet ring is close enough to the PAS sensor. The magnet ring should be about 3 mm (about the thickness of two stacked credit cards) away from the PAS sensor. Use the photo below for reference.

    PAS_spacing.PNG
    If the magnet ring is far from the PAS sensor, gently push the magnet ring closer to the PAS sensor, making sure it stays square with the bottom bracket spindle and isn't crooked such that it "wobbles" when spun.
    If the magnet ring is close enough to the PAS sensor, continue to the next step.
  5. Visually inspect the magnet ring for dirt or damage. The magnets on the ring should be clear and unobstructed so they can send a strong signal to the PAS sensor.

    Magnet_ring.png
    If the magnet ring is dirty, gently clean off the dirt with a clean and dry shop or paper towel. If needed, use warm water to slightly dampen the clean towel, gently wipe the magnet ring clean, and pat dry.
    If the magnet ring is damaged, it may need to be replaced. Contact us for more help, and be sure to attach the video you recorded to your request.
    If the magnet ring is clean and not damaged, continue to the next step.
  6. Unplug and inspect the PAS sensor connector.
    1. Trace the cable coming out of the PAS sensor to the connector. Snip zip ties as needed to access the connector.
    2. Unplug the connector by pulling each side directly apart without twisting.
    3. Inspect the inside of the connector for dirt, damage, or moisture.

      PAS_connector.PNG
      If the inside of the connector is dirty, damaged, or wet, the sensor may need to be replaced. Contact us for more help, and be sure to attach the video you recorded to your request.
      If the inside of the connector looks normal, plug in the connector. Line up the internal notch and pins (and external arrows) and press each side directly together, without twisting. Replace the zip tie and trim it to be flush and smooth. Then move on to the next step.
  7. Reinstall the battery and turn on the bike.
  8. Inspect the PAS sensor LED.
    1. Set the PAS level to 1 on the display. 
    2. Prop the bike on the kickstand and tilt it slightly to the side so the rear wheel is off the ground.
    3. Rotate the crank forward with your hand and look at the PAS sensor to see if the LED illuminates and blinks while pedaling. Keep clear of the rear wheel as it moves.

      PAS_light.PNG
      If the PAS sensor LED is on and solid while pedaling, or if the light is not on, the sensor may need to be replaced. Contact us for more help, and be sure to attach the video you recorded to your request.
      If the PAS sensor LED is on and blinking while pedaling, continue to the next step.
  9. Ride the bike in a safe and open area to test if the PAS issue is resolved.
    If the issue continues, contact us for more help, and be sure to attach the video you recorded to your request.
    If the issue is resolved, test the bike fully, and ride Rad!

Need more assistance?  Submit a request