Toro Groundsmaster
3500-D - Standard-Control Module (SCM); SCM Overview and Troubleshooting

Standard-ControlModule
(SCM)
TheStandard-ControlModule(SCM)isapotted
electronicdeviceproducedina1-size-ts-all
conguration.Themoduleusessolidstateand
mechanicalcomponentstomonitorandcontrol
standard,electricalfeaturesrequiredforsafeproduct
operation.
Themodule-monitorinputincludesneutral,parking
brake,PTO,start,backlap,andhightemperature.
ThemoduleenergizesoutputsincludingPTO,Starter,
andETR(energizetorun)solenoid.
Themoduleisdividedintoinputsandoutputs.Inputs
andoutputsareidentiedbygreenLEDindicators
mountedontheprintedcircuitboard.
Thestart-circuitinputisenergizedby12VDC.All
otherinputsareenergizedwhenthecircuitisclosed
toground.EachinputhasanLEDthatilluminates
whenthespeciccircuitisenergized.Usetheinput
LEDsforswitchandinput-circuittroubleshooting.
Outputcircuitsareenergizedbyanappropriatesetof
inputconditions.The3outputsincludePTO,ETR,
andSTART.OutputLEDsmonitortherelaycondition,
indicatingthepresenceofvoltageat1of3specic
outputterminals.
Outputcircuitsdonotdetermineoutput-device
integrity,soelectricaltroubleshootingincludes
output-LEDinspection,conventionaldevice,
andwire-harness-integritytesting.Measurethe
disconnected-componentimpedance,impedance
throughthewireharness(disconnectatSCM),orby
temporarily”testenergizing”thespeciccomponent.
TheSCMdoesnotconnecttoanexternalcomputeror
handhelddevice,cannotbeprogrammedagain,and
doesnotrecordintermittentfaulttroubleshootingdata.
ThedecalontheSCMincludesonlysymbols.The
3LEDoutputsymbolsareshownintheoutputbox,
whileallotherLEDsareinputsasshowninFigure29.
g031611
Figure29
1.Backlap(input)7.PTO(output)
2.Hightemperature(input)8.Start(output)
3.Inseat(input)9.ETR(output)
4.PTOswitch(input)10.Start(input)
5.Parkingbrake—off(input)11.Power(input)
6.Neutralposition(input)
TotroubleshoottheSCMdevice,dothefollowing
steps:
1.Determinetheoutputfaultthatyouaretryingto
resolve(PTO,START ,orETR).
2.MovekeyswitchtotheONpositionandensure
thatthered,powerLEDilluminates.
3.Movealloftheinputswitchestoensurethatall
LEDschangestate.
4.Positiontheinputdevicesattheappropriate
positiontoachievetheappropriateoutput.
Note:Usethefollowinglogiccharttodetermine
theappropriateinputcondition.
5.Reviewthefollowingrepairoptionsifaspecic
outputLEDilluminates.
•IfaspecicoutputLEDilluminateswithout
theappropriateoutputfunction,check
theoutputharness,connections,and
component.
Note:Repairasrequired.
•IfaspecicoutputLEDdoesnotilluminate,
checkbothfuses.
•IfaspecicoutputLEDdoesnotilluminate
andtheinputsareintheappropriate
condition,installanewSCManddetermine
ifthefaultdisappears.
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