Troubleshooting

If you can’t get your motor controller to work, then here are some troubleshooting steps that may help you find the problem;

  • Is the “high pot lockout” feature activating? [not Porter or DNO].
  • Do you have full battery voltage across the B- and B+ terminals on the controller whilst under load ? [we see a lot of problems that are caused by bad joints in the battery wiring, and also by batteries that have one dead cell].
  • Are the motor cables securely attached?
  • Check the motor cables for continuity.
  • Most 4QD controllers are fitted with fuse tracks on the circuit board, check that none of these are blown [see your manual for details].
  • Tip; when we are fault finding we disconnect the motor and connect a bulb [of suitable voltage] across M- / M+ with flying leads

DNO, Pro, and VTX models

Remove the controller cover, plug the control cable back in, then check the following voltages on the back of the grey 6 way connector close to the relays.

Wire colour Voltage [with respect to B-] If it’s not….
Green 0 Wiring fault
Blue 0 – 7V [Pro-150=5V] changes with pot position Wiring or pot fault
Red Approx 7V [Pro-150=5V] Wiring or controller fault
Black 0 or B+, changes with reverse switch Wiring or switch fault
White 0 or B+, changes with ignition switch Wiring or switch fault
Yellow B+ Wiring fault or blown fuse track

 

4QD-200 / 300 models

Remove the controller cover and check the following voltages on the pins of the grey 6 way connector on the top board [you should do this from above the board]

Pin letter Voltage [with respect to B-] If it’s not….
A Approx 11V [0V if inhibit switch active] Wiring fault
B 0V with ignition off,             11V with ignition on Wiring or controller fault
C 0 or B+*, changes with reverse switch [* can be 11V if alternative wiring used] Wiring or reverse switch fault
D Approx 11V Wiring or controller fault
E 0 – 11V, changes with pot position Wiring or pot fault
F  0V

Also check the following voltages on the back of the grey 4 way connector on the bottom board

Pin letter Voltage [with respect to B-] If it’s not….
A
B
C 0 or B+, changes with ignition switch Wiring or switch fault
D B+ Wiring fault

We also have some general fault finding tips for the 4QD series here, and some instructions on how to test the base board and MOSFETs here.

Porter 5 / 10

Remove the controller cover, plug the control cable back in, then check the following voltages on the pins of the grey 5 way connector on the board.

Pin letter Voltage [with respect to B-] If it’s not….
A 0 – 0.5V Wiring or controller fault
B 0 – 0.5V Wiring or controller fault
C 1-4V, changes with pot position Wiring or pot fault
D 5V Wiring or controller fault
E 5V Wiring or controller fault

 

 

There are also some model specific fault finding tips in the manual for each controller.