MG MG6 Series 2011 - Page 238

Engine
EngineCoolingSystem
Heatedcoolantexitsthecoolantelbowandenterstheheater
matrixfeedpipeandisfedtotheheatermatrix.Duringengine
operation,coolantisconstantlycirculatedthroughtheheater
matrixbythecoolantpipe.Thecoolantexitsthematrixvia
thereturnpipetoberecirculated.
CoolingFanStrategy
Thecoolingfanwilloperateathighorlowspeeds.Control
isachievedbytheECMandtherelayunit.TheECMuses
informationprovidedbytheECTsensor,theBCMandthe
A/Cpressuresensortocontrolfanspeedassolimitengine
coolanttemperature.
Duringnormalrunning,thefanwilloperateatthefollowing
coolanttemperatures:
Coolingfanstatus
LowspeedHighspeed
ON
100
℃ ℃
℃
112℃ ℃
℃
OFF
94℃ ℃
℃
106℃ ℃
℃
Duringnormalrunning,thefanwilloperateatthefollowing
pressure:
Coolingfanstatus
LowspeedHighspeed
ON
17bar
22bar
OFF10bar19bar
Thefanstrategyincludesanengineidleadjustmentto
compensatefortheadditionalloadwhenswitchingonthe
fan.Thecoolingfanmayrunforaperiodof5minutesifthe
coolanttemperatureexceeds104℃ ℃
℃
,afterthehandsetis
removedtoprovideadditionalenginecoolinginhotambient
conditions.IntheeventofECTfailure,thefanwilloperateat
itslowspeed.
CoolingFanRelayUnit
ThefancontrolrelayunitisconnectedtotheECMbytwo
wires,thesewiressupplyagroundpathtotheinternalrelay
windings.Thecoolingfanrelayreceivesa12Vsupplythrough
fuse4intheenginecompartmentfusebox.Thefanmotoris
drivenbytheoutputfromtheinternalrelaysthroughfuse4in
theenginecompartmentfusebox.T oproduceaslowfanspeed
theECMprovidesagroundpathtopin1ofconnectorEB037
attherelay.T oproduceafastfanspeedtheECMprovidesa
groundpathtopin2ofconnectorEB036attherelay.
Thecoolingfanrelaycouldfailinthefollowingways:
•Highspeedrelaywindingopencircuit
•Highspeedrelaywindingshortcircuit
•Highspeedrelaycontactshighresistance
•Highspeedrelaycontactsopencircuit
•Lowspeedrelaywindingopencircuit
•Lowspeedrelaywindingshortcircuit
•Lowspeedrelaycontactshighresistance
•Externalwiringopencircuit
•Externalwiringshortcircuitto12V
•Externalwiringshortcircuittoground
•Externalwiringhighresistance
Warning:Keepclearofthecoolingfan.Thefanmaystart
automaticallywithoutwarning,evenaftertheengineis
turnedoff.
CoolantLevelSensor
Whenthecoolantiswithinthe‘MAX'and‘MIN'limitsmarked
onthesideoftheexpansiontank,thesensoroatwillbe
inthe'high'positiongeneratinganopencircuitcondition.If
thecoolantlevelfalls,theoatwilldroptothe'low'position
closingthecircuit,sendingasignaltothe
ECM.TheECM
sendsasignalviatheHSCANbustotheBCMBCMwhich
passesthesignalviatheMSCANbustotheinstrumentpack,
illuminatingthewarningmessageandalertingthedrivertoany
dropincoolantlevel.
Version2.0
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