HeyBike Mars error 21 on display

the sound might've been something on the bike hitting wheel spokes, or it could've been brake pads catching in rotor holes before disintegrating, or a wire being caught in the caliper/rotor.

if it was a wire hitting the spokes or rotor was damaged, it could cause errors.

you'd have to check your manual for what 21 is for your system, but it's a common error message on other threads here you might be able to use info from to test yours. the list linked below is only looking at titles for the error, but you can do a search for posts as well if you don't see what you want in this list.

Hi, so I have tried to open the controller box at the bottom of my HeyBike Mars, but every connection looked great. So I would say that the electronic part might be fine. The back tire still makes the noise, however, when I put WD-40 in the motor, it seems that the noise goes away… but then one day later it comes back. Any ideas?

Hello everyone,

Can someone tell how much a motor for an HeyBike Mars usually lasts?

I am having problems with the motor of my HeyBike Mars that I bought in 2022 and with which I made around 5000 miles and I was considering in buying a completely new motor.

Also, any suggestion on which motor I should replace the original one?

Thanks in advance

You haven't said why you think it's the motor. Other components of the system are far more likely to be the source of problems. Most likely of all it's a plug or cable. But you haven't said anything that would indicate what is going on.

So maybe describe the symptoms you're getting as thoroughly as you can, and say what your riding conditions/habits were like when you started having issues.

Hi,
Yes so, the first issue was the PAS. It stopped working all of a sudden. Afterwards, at around 4000 miles, the range on the display “disappeared”(since it was a year ago, I assume I have put 1000 more miles on the e-bike since then).

Afterwards, while I was riding my HeyBike Mars, I heard a crack while and error 21 started to be displayed on the display. Ever since, the display shows error 21 and there is noise coming from the rear tire. The noise is a metallic one, therefore I assumed it had to be the inside of the motor as, from outside, the rear tire looks fine.

I also inspected the wires of the controller and all the outside wires and they seem intact.

Also, when I turn the key in the battery, the motor spins(and the tire with it) for 1/4 of a second before switching all the system of the E-bike off.

Fde12341234! said:

Yes so, the first issue was the PAS. It stopped working all of a sudden.

Click to expand...

That's the first clue it isn't the motor. PAS is a discussion that happens between the pedal sensor and the controller. Motor isn't involved.

Fde12341234! said:

Afterwards, at around 4000 miles, the range on the display “disappeared”(since it was a year ago, I assume I have put 1000 more miles on the e-bike since then).

Click to expand...

That sounds like a display problem. If you're talking about the cartoon battery with a number of bars on it to represent capacity, those things are notoriously inaccurate and unreliable in my observation. I think they're a waste of time, and I rely solely on battery voltage to tell me how much range I have remaining.

Fde12341234! said:

Afterwards, while I was riding my HeyBike Mars, I heard a crack while and error 21 started to be displayed on the display. Ever since, the display shows error 21 and there is noise coming from the rear tire. The noise is a metallic one, therefore I assumed it had to be the inside of the motor as, from outside, the rear tire looks fine.

Click to expand...

Assuming the "crack" sound wasn't an electrical arc, then that seems like it could be a Hall sensor wire or phase wire continuity problem that made the motor briefly depower and then repower (or briefly reverse and then resume forward operation), whacking through the backlash in its gear train. Carefully inspect the motor to controller plugs (at both ends of the extension cable if you have one) and look for bent pins, discoloration, corrosion, and heat damage.

Fde12341234! said:

Also, when I turn the key in the battery, the motor spins(and the tire with it) for 1/4 of a second before switching all the system of the E-bike off.

Click to expand...

In isolation, that seems like it could be a battery balance or BMS problem. (But it could also be a phase and Hall problem.) Do you run the battery all the way to empty very often?

I keep a test rig at work that is a very cheap 18A controller with learning wires, a throttle, and a small assortment of battery and motor adapter cables for testing motors of unknown provenance. If a motor from a non-working e-bike runs fine on my test controller, then I can eliminate the motor as a cause of the failure.

The controller is dual mode (with and without Hall sensors), so that I can test motors that lack Hall sensors. But I also keep a cheapo e-bike tester device that can independently check Hall sensor signals if I suspect them of problems.

I looked at your updated top post. The brakes of your bike are unrelated to the electric components, except for switches in the levers that cut power to the motor when you apply the brakes. So a brake failure is probably a maintenance issue but not an electrical one. It makes me wonder if the click you are hearing isn't a damaged brake rotor.

To prohibit the brakes from interacting with your motor drive, unplug the brake levers.

I got this from googling "Heybike Mars error codes":

(1) Error Code: 21 – Abnormal Current

① Problem Description: The motor doesn’t work and the PAS mode is ineffective.

② Step-by-Step Solution: First, please check whether all the cables are firmly connected, whether the pin inside the connector is deformed, whether the connector is aligned with the arrow, and whether there is a broken line or short circuit. If you find any connection problems, please try reconnection or replace the damaged wire.

If all connections are fine, please disconnect the PAS sensor and then restart the display to see if the e-bike operates normally. If yes, the PAS sensor should be replaced. If the error code still exists, the controller should be replaced.

③ Apply to E-bike Models: Cityscape, Mars, Race, Ranger, Explore, Cityrun, Brawn, Tyson, Ranger S, Horizon, Mars 2.0, Hauler, Hero.

Click to expand...

Thanks a lot for your reply.

Yes, most of the times I was running the battery all the way to empty very often.

The first noise I heard was exactly when I used the breaks... I had to stop at a stop, I used the breaks and the metallic noise happened. Since then, the motor keeps making the same noise... it looks like something is constantly hitting something. I also opened the motor, however, I did not spend lots of time looking at the wires as I did not have the proper tools to check if it was working or not.

Yes I have plugged and unplugged several times the sensor but still it is not working... the constant metallic sound made me think of something hitting something else inside the motor (as you said probably the Hall sensor)

Fde12341234! said:

the constant metallic sound made me think of something hitting something else inside the motor (as you said probably the Hall sensor)

Click to expand...

I would very much suspect the disc brake rather than the motor. Remove the caliper and tie it out of the way, and see if the noise doesn't stop.

Sounds good, I will do that and let you know how it goes!!

So the metallic noise is not there anymore, it was the chain that was not oiled properly and was hitting the metallic part of the toothing.

However, now when I turn the bike on, the motor still spins for 1/4 of a second, then the bike shuts off.

It still does it when I unplug the brakes’ wires and the PAS wire. It does it only when the wire that is attached to the motor is plugged to the controller.

Put the battery on the charger and leave it there as long as you can stand. If the BMS does any balancing, it's a very slow process that occurs only when the battery is fully charged and still on the charger. Leave the battery a couple of days on the charger and then see if it behaves better. If so, your BMS has been doing its job keeping you (somewhat) from brutalizing that battery into an unsafe condition. You can give it a longer charge and see if it improves further.

If the battery does work better after a long balancing charge, that doesn't mean you haven't wrecked it by running it down all the way, all the time. It just confirms that your battery is a key problem. But to me it sounds like the whole bike likely has been knackered by lack of maintenance and harsh operating conditions.

Ok, will do that and let you know. Thanks for your time