22
Troubleshooting
ELECTRICAL SYSTEM AND TESTING:
ELECTRIC VEHICLES
TROUBLESHOOTING GUIDE 1
SYMPTOM
POSSIBLE CAUSES
CORRECTIVE ACTION
Speed controller logic malfunction
Failed controller FET (that powers up solenoid
coil)
Disconnect the batteries and allow the speed
controller capacitors to discharge.
See WARNING
“To avoid unintentionally starting...” in See
Reconnect the
batteries and see if the symptom returns.
Loose, broken, or disconnected wire(s) at solenoid
or B+ speed controller terminal
Repair and/or connect the loose or disconnected
wire(s)
Loose or disconnected 24-pin connector at speed
controller or broken wire
Repair and/or connect the 24-pin connector to the
speed controller
Monitor Menu – MAIN CONT (solenoid)
does not indicate ON when the solenoid
should be activated. or Diagnostic
Menu – MAIN CONT DNC (main
contactor (solenoid) did not close) fault
code
Failed solenoid
Replace solenoid.
Loose or disconnected wires at key switch
terminals or broken wire
Repair and/or connect the quick disconnect
terminals to the Forward/Reverse switch
Loose or disconnected 24-pin connector at speed
controller or broken wire
Repair and/or connect the 24-pin connector to the
speed controller
Monitor Menu – KEY INPUT does not
indicate ON when key switch is in the
ON position
Failed key switch
Test Procedure 9 – Key Switch and MCOR Limit
Loose or disconnected three-pin connector at the
MCOR or broken wire
Repair and/or connect the three-pin connector to
the MCOR
Loose or disconnected 24-pin connector at speed
controller or broken wire
Repair and/or connect the 24-pin connector to the
speed controller
Diagnostic Menu – THROTTLE FAULT
1 fault code
Failed MCOR
Test Procedure 4 – MCOR Voltage on page 22-13
Armature drive FET’s (field-effect transistors)
inside speed controller have failed
Replace the speed controller.
Controller Removal on page 24-12.
Diagnostic Menu – HW FAILSAFE
(Hardware Failsafe) fault code
Speed controller logic malfunction
Disconnect the batteries and allow the speed
controller capacitors to discharge.
See WARNING
“To avoid unintentionally starting...” in See
Reconnect the
batteries and see if the symptom returns.
Diagnostic Menu – MAIN WELDED
(main solenoid contacts welded) fault
code
solenoid contacts have failed closed
Replace solenoid.
Speed controller logic malfunction
Disconnect the batteries and allow the speed
controller capacitors to discharge.
See WARNING
“To avoid unintentionally starting...” in See
Reconnect the
batteries and see if the symptom returns.
Diagnostic Menu – MAIN DRIVER ON
or MAIN DRIVER OFF fault code
Failure of the FET that controls the solenoid coil
Replace the speed controller.
Controller Removal on page 24-12.
Diagnostic Menu – MAIN COIL FAULT
fault code or Diagnostic Menu – MAIN
DROPOUT fault code
Solenoid coil has failed in an open condition or
broken wire to solenoid coil
Replace solenoid.
TABLE CONTINUED ON NEXT PAGE
Page 22-6
2007-2009 Turf 252, Carryall 252 and XRT 900 Maintenance and Service Manual