Brand new, Magic pie 5 showing error code 9

[Dean]

Hi, I recently purchased a Magic Pie 5, brand new straight out of the box its display would show error code 9,and flashing low battery, also no power to the motor even though the throttle was fully lit. I did a little research and found out Error 9 was a communication error. Upon reading about this code, I've tried all the suggestions the forums gave test try and fix/isolate the problem. I've tried disconnecting the display to see if I would get power to the motor, checking the brakes for sticking, and disconnecting the brakes then recycling the battery, refreshing the controller. I've even tried a spare 48v battery I had, after everything still same results, error 9, flashing low battery, and no power to the motor. I contacted GM, and they sent out a new controller,  hooked it up, still code 9. GM asked if I could send all the parts back to them except the motor itself, so they could recreate the problem I'm having, so they could pinpoint the problem.  I sent everything back, GM contacted and said that they were unable to recreate the problem, that everything was working the way it was supposed to. GM knows that I did have this issue, because I sent them pictures showing the error code. They have been very helpful in trying to find a solution to this intermittent problem. I was hoping that maybe someone would have some insight as to why this is happening.  Thanks

[Bikemad]

Hi Dean andto the forum.

If you don't have motor power after disconnecting the display unit and the brakes, the problem is most probably due to one of the remaining components, i.e. the throttle, control harness, motor harness/controller, pedelec sensor (if fitted) or the motor Hall sensors.

I seem to recall that there are two versions of the BAC-601 LCD display units as the earlier MP4 displays were not compatible with the MP5.

When I produced the wiring diagrams for the MP4 and MP5, the only difference I observed was that the MP5 had a +5V feed on pin 4 of the 5 pin connector on the motor harness, whereas the MP4 controller harness that I tested did not have anything connected to pin 4:





Assuming that the later display relies on the +5V supply to work correctly, an intermittent +5V supply could be causing your particular problem.

This +5V supply is produced by a 5V regulator chip that is built into the controller, and its 5V output is then sent via the motor harness and control harness to supply several of the connectors (control harness, brakes, throttle, pedelec and the motor Hall Sensors).

Unfortunately, finding the precise cause of an intermittent fault can be extremely difficult, as you really need the fault to be active in order to diagnose the problem by disconnecting/substituting things or measuring voltages etc. to try and pinpoint the cause.

While the fault is active, turn Off the battery power and disconnect the main 10 pin connector between the motor and control harness (and unplug the pedelec sensor if fitted) and then turn the battery power back On again to see if the battery gauge on the BAC-601 display fills up correctly. You may also see an error 2 because the throttle is no longer connected.

If the gauge still doesn't display correctly and the error 9 is still showing, the problem must be somewhere within the wheel or the controller harness assembly that is causing the fault. This would seem to indicate a Hall Sensor or wiring fault within the motor itself, as a new replacement controller and motor harness is unlikely to exhibit the exact same problem. 

However, if disconnecting the 10 pin connector does allow the Battery gauge to work correctly, I suspect the problem will be either the control harness itself, or something connected to it.
In which case, you will need to disconnect everything from the control harness (brakes, throttle and cruise/horn button) and then plug the control harness back into the motor. You may still see an error 2 with the throttle disconnected, but if the error 9 instantly returns, the fault is probably a partially or fully short circuit connection somewhere within the control harness itself.

If the error 9 doesn't return, plug in the throttle unit and see if the motor runs (or the error 9 appears).

If plugging in the throttle instantly causes the error 9, a replacement throttle should cure the problem, however, if the motor runs and no error codes are displayed, try plugging in the brake connectors and the cruise/horn button one at a time to see what happens.

If you get to the stage where everything is plugged back in again but the fault has not reappeared, try wriggling the various wires and connectors etc. to see if you can cause the fault to reappear.

If you cannot reproduce the fault you may have to wait until it occurs again and then repeat the above tests again 

I experienced an error 9 problem on my MP4 many years ago:

But it only occured when I was testing the operation of the brake lever switches on a stationary bike with full throttle applied, and this must have somehow upset the controller. 

Turning the battery Off and back On again instantly cured the error, which has not returned since.

Alan
 

[Bikemad]

I tried to reproduce the error 9 fault on my MP4 earlier today by doing the same as I did the last time it happened, but I couldn't get it to appear. However, after several attempts at straining the controller (like I did before) I ended up with an Error 3 fault being displayed which indicates a Hall Failure or Phase problem.
This was accompanied by a severe loss of power and just a very slight pulse at the wheel instead of the strong force it usually applies when the throttle is applied when the wheel is stationary.

I disconnected and reconnected the battery but, unlike the last time, the error 3 fault and the almost complete loss of power was still present. I eventually managed to get it working normally again by raising the wheel off the ground and then applying the throttle to spin the wheel freely.
This seemed to reset the fault, and the strong torque thankfully returned again.

I suspect that I did not leave the battery disconnected long enough for the controller's capacitors to drain low enough for the microcontroller to reset itself, therefore it still retained the previous fault condition within the Microcontroller's volatile memory. Presumably, the rotation of the motor allowed the controller to confirm that everything was in fact working correctly and its firmware allows it to override/reset the error itself. 

This could mean that you may have to leave your battery disconnected for longer (or place a light bulb across the controller's battery cables while it is disconnected) to ensure the controller is fully discharged and reset between each of the suggested tests. 

If you haven't already done so, try having just the BAC-601 display connected to the motor and then plug the controller into the battery with everything else left disconnected and see if you get the expected Error 2 (because the throttle will be disconnected) or the error 9 because the controller is unable to communicate with the display unit.

I don't know which battery you are using, but does it by any chance have a USB socket for powering/charging phones etc.?
Some buck converters can adversely affect the correct functioning of electronic devices by inadvertently allowing high-frequency noise on the input supply of a buck converter to be passed along the battery cables. 

If the battery power is switched electronically via MOSFETs in the BMS instead of simply going directly through the mechanical contacts of a high current switch, it may be worth turning the battery on before you connect the controller to see if it makes any difference.

You should hear/see a brief spark as the controller's battery wires are connected to the battery, which is caused by the inrush current instantly filling up the controller's capacitors until they are equal to the battery voltage. 

I sometimes use a variable voltage power supply to power up controllers for programming purposes while testing them indoors, and I have noticed that they sometimes do not connect if I slowly increase the voltage from 0 to 48V, as opposed to turning the power supply on with the output voltage already preset to 48V.

If this delayed power-up can prevent a controller from connecting to the USB programming cable correctly, presumably it could also prevent the controller from connecting to the BAC-601 display in a similar way.
As I  said before, I don't know what battery you have, or whether this could possibly be causing the error 9, but it's certainly worth giving it a try to see if it makes any difference.

Are you able to connect and access the programmable parameters of the controller using either the USB programming lead and PI800 software on a PC/laptop or the Bluetooth dongle and GM's Bluetooth App?

Alan