Bafang 500W Hub Motor & SW900 Display: Error 007

[WholesomeSpider]

Hi, was hoping for some help with my bike.
Specs
Motor: Rear Wheel mounted Bafang RM G020.500D 12 (as printed on hub)
Display: Monochrome SW900 firmware V1.0
Battery: 48V 14Ah (as per battery sticker)
Controller: ???

Problem
Constant error 007 on the display on startup
The bike mostly starts with err 007:

1. If I throttle the motor makes a low grind noise, and then err 007 will display OR
2. If I turn the PAS up past 1 and turn the wheels the motor make a low grind noise and err 07 displays OR
3. If i roll the bike backwards err 007 occurs

In the efforts of getting as much information to ask for help I took the motor apart and did the following testing:

• Manually rotated the outer ring and it turns smoothly.
• I hooked the motor up to power and tested with the throttle and the motor turns with a ‘clicky’ noise.
• I tested each hall sensor diodes with a multi meter and got values (however I am the first to admit I have no idea what these values mean):
  • 0.909
  • 0.894
  • 0.890

I have attached photos and videos of each test incase that helps.

Videos:

https://imgur.com/a/sVKM6Fp

I have also unplugged/reconnected the Juliet connector to the motor and the 5 pin hall sensor connector at the controller end

Any advice/direction would be greatly appreciated.

 

[WholesomeSpider]

For anyone else facing this problem, I resolved it by replacing the small hall sensors mounted on the motor. I’m still not sure which ones were broken; my skills are limited so I simply replaced all three.

I took the bike to a shop for a quote on repairs. They said I needed to replace the motor core, which I believe would have included the hall sensors. The total cost was $AUD 540 for parts and labour. I thought I could buy a whole new motor from AliExpress for less so I decided to try and fix it myself. If I completely screwed it up I would just buy the new motor.

I bought hall sensors off aliexpress:
10PCS Electrocar Motor Hall Sensor 3144 41F 43F 413 With High Temperature Insulation Sleeve Hall Element Switch 13A A44E Sensor

I used the technique from this YouTube video to solder the hall sensors to the PCB.

Removing the hall sensors was a bit of a pain, I had to use a heat gun to loosen whatever was sticking them in and pull them out with needle nose pliers.

Hall Sensor Pack was ~$AUD 2.50

You’ll need a soldering iron and a Torx 20 driver/bit to remove the motor cover. It might have been a security or safety Torx head.

Hope this helps someone else if they come across the same problem.