ESP PORSCHE 911 CARRERA 2003 4.G Repair Manual

Convertibletop
I>Neverremovesnowandiceusingasharp
edgedobject.
Incorrectcareandtreatmentcandamagethe
convertibletopandcauseleaks.Anyrepairwork
canbedonebyyourauthorizedPorschedealer.

Importantnote
Nofoldingtopis100%leakproof.

Duetotheconstantchangingofloadsand
strainstowhichacarissubjecttowhendriving
onroads,minorwindnoiseandseepageat
jointsbetweenthetop,bodyanddoorsoncon-
vertibletopscannotbecompletelysealedincer-
tainareas.Thereforesmallleaksareconsidered
normalforthesemodels.Inaddition,yourcon-
vertibletopshouldnotbewashedinacarwash.
Thetopmayexperiencedamagebythebrushes
ormayexperienceleaksduetothehighpress-
urewaterstreamsdirectedinareaswhichwould
notencounterwaterinnormaldrivingconditions.
Cleaning
Donotwashtheconvertibletopeachtimethe
cariswashed.
Itisusuallysufficienttosprayorwashitwith
cleanwater.
I>Brushdustofftheconvertibletopinthedirec-
tionoftheweaveusingasoftbrush.
I>Onlyifthereisheavydirt,wettheconvertible
topwithlukewarmwaterandthePorsche
Wash-Shampoo&convertible-topcleaner,
usingaspongeorsoftbrush,andrubgently.
RinseWash-Shampoo&convertible-top
cleanerthoroughlyofftheconvertibletopwith
cleanwater.
I>Afterwashingit,treattheconvertible-top
coveratleastonceayearwiththespecial
Porscheconvertible-topcareproduct.
Donotallowtheconvertible-topcareproduct
tocomeintocontactwithpaintorwindows.If
itdoes,removeimmediately.
I>Ifthereisleakageintheconvertible-topcover
oratitsseamsorfolds,thespecialPorsche
convertible-topcareproductcanbeused.
I>Pleasenotetheinformationonthecontainer.
I>Removebirddroppingsimmediatelysincethe
acidinthemwillmaketherubberswelland
theconvertibletopwillbecomeleaky.
I>Openconvertibletoponlywhenitiscom-
pletelydry,otherwisedampstainsandscrub
marksmayoccurwhichcannotberemoved.
I>Trytoremovespotsfromtheconvertible-top
coverbyrubbingcarefullywithasoftrubber
sponge.
Doorlocks
I>Topreventthedoorlocksfromfreezingdur-
ingthecoldseason,thelockcylindersshould
becoveredduringawash.
I>Shouldthelocksfreeze,useanordinaryde-
icer.Inmanycases,awellwarmedkeycan
help.
Neveruseexcessiveforce.
I>I>I>
Maintenance,CarCare
187

Enginecompartment
Theenginecompartmentandthesurfaceofthe
enginearetreatedwithacorrosion-inhibitorat
thefactory.
Ifdegreasingsolventsareusedtocleantheen-
ginecompartmentortheengineiswashed
down,theprocessalmostinvariablyremoves
thecorrosion-inhibitingcoating.Itisthenabso-
lutelynecessarytohaveadurablepreservative
appliedtoallsurfaces,bodyseams,jointsand
assembliesintheenginecompartment.Thisalso
applieswhencorrosion-inhibitorpartsarere-
placed.
Effectivecorrosion-proofingisparticularlyimport-
antduringthecoldweatherseason.Ifyourcar
isdrivenfrequentlyinareaswheresalthasbeen
spreadontheroads,thewholeenginecompart-
mentshouldbecleanedthoroughlyafterthe
wintertopreventsaltfromcausinganylasting
damage.Afullunder-bodywashshouldalsobe
performedatthesametime.
ACaution!
Riskofdamagetothegenerator.
I>Donotpointthecleaningjetdirectlyatthe
generator,orcoverthegenerator.
Windows
Theroaddustwhichsettlesonthewindshield
andwindowscontainsparticlesoftirerubber
andoilresidue.Theinteriortrimandupholstery
releaseparticles,particularlyinstrongsunlight,
whichcollectontheinsidesofthewindows.
Thesedepositsareaugmentedbyimpuritiesin
theairwhichentersthecarthroughthefreshair
vents.
I>Cleanallwindowsregularly,insideandout-
side,withPorschewindowcleaner.
I>Ifyouuseachamoisleatherforthewindows,
donotuseitforpaintworkasitwillotherwise
pickupacertainamountofpreservativeor
polishandcouldsmearthewindowsandthus
impairvision.
I>RemovedeadinsectswiththePorscheinsect
remover.
Wiperblades
Wiperbladesthatareinperfektconditionare
vitalforaclearview.
I>Replacethewiperbladestwiceperyear(be-
foreandafterthecoldseason)orwhenever
wiperperformancedeteriorates.
I>Periodicallycleanthewiperbladeswith
Porschewindowcleaner,especiallyafterthe
vehiclehasbeenwashedinacarwash.
Iftheyareverydirty(e.g.withinsectre-
mains),theycanbecleanedwithaspongeor
cloth.
Undercoating
Theundersideofyourcarisdurablyprotected
againstchemicalandmechanicalinfluences.
Asitisnotpossibletoexcludetheriskofdam-
agetothisprotectivecoatingindaytodaydriv-
ing,itisadvisabletohavetheundersideofthe
carinspectedatcertainintervals-preferablybe-
forethestartofwinterandagaininspring-and
theundercoatingrestoredasnecessary.
YourauthorizedPorschedealerisfamiliarwith
thebodysealtreatmentproceduresandhasthe
necessaryequipmentforapplyingfactoryap-
provedmaterials.Werecommendthatyouen-
trustthemwithsuchworkandinspections.
Unlikeconventionalsprayoils,undercoatingand
rust-proofingcompoundsbasedonbitumenor
waxdonotattackthesound-proofingmaterials
appliedatthefactory.
I>I>I>
Maintenance,CarCare
189

Fabric,upholstery,carpetsand
floor-mats
t>Useonlyavacuumcleaneroramediumstiff
brush.
t>RemovestainsandspotswithPorschestain
remover.
ThePorscherangeofaccessoriesincludes
floor-matstoprotectthecarpetsinsummerand
winter.
A
Warning!
Riskofanaccident.
t>Alwayscheckthemovementofthepedalsbe-
foredrivingandmakesurethattheyarenot
obstructedbyafloormatoranyotherobject.
t>Securethefloormattopreventitfromsliding
intopositionsthatcouldinterferewiththe
safeoperationofyourvehicle-donotlie
themlooselyinthevehicle.
YourPorschedealerwillbegladtoofferyou
floormatsofthecorrectsizeincludingase-
curingpossibility.
192Maintenance,CarCare
Alcantara
Donotusealeathercareproducttoclean
Alcantara.
Forregularcareitissufficienttocleanthe
coverwithasoftbrush.
Cleaningwhenlightlysoiled
t>Wetasoftclothwithwateroraneutralsoap
solutionandwipeoffthedirt.
Cleaningwhenheavilysoiled
t>Wetasoftclothwithlukewarmwateror
thinnedwhitespiritanddabthedirtfromthe
outsidein.

Safetybelts

Ifitbecomesnecessarytocleanthebelts,you
canuseanymildwashingagent.
Allowthebeltstodrypriortoretracting,but
avoiddirectsunlight.
t>Onlyusesuitablecleaners.
Ifunsuitablecleanersareusedoranyattempt
ismadetodyeorbleachthebelts,theweb-
bingmaybeweakenedandthusconstitutea
safetyrisk.

Storing
yourPorsche
IfyouintendtostoreyourPorscheforapro-
longedperiod,pleaseconsultyourauthorized
Porschedealer.Thestaffwillbegladtoadvise
youonthemostsuitableandnecessary
methods.
I>Cleanyourvehiclethoroughlyinsideandout-
side.
Cleantheenginecompartment.
Theundercarriageandchassiscomponents
shouldbefreeofdirtandsaltdeposits.
I>Fillupthefueltank.
I>Changetheoilandoilfilter,andruntheen-
gineforseveralminutes.
I>Increasethetirepressureto58psi(4bar).
Itisnotrecommendedtoliftthevehicle,due
tothepossibilityofcorrosiononshockabsor-
berpistonshafts.
Thevehicleshouldbemovedslightly,approxi-
matelyeveryfourweeks,topreventflatspot
onthetires.
Climatecontrol
Theairconditioningsystemshouldbeingood
workingconditionandfullycharged.
Windshield/Headlightwasher
I>Checkandcorrectantifreeze/cleaningsolu-
tionlevelasnecessary.
Electricalsystem
I>Removethebatteryfromthevehicleand
storeitinacooldryplace,notonacement
floor.
Whenthebatteryisdisconnected,the
alarmsystemisdeactivated.
I>Rechargethebatteryevery3months.Ifthe
batteryremainsinthevehiclewiththecables
connected,itisnecessarytocheck,remove
andrechargethebatteryevery2-3weeks.

Donotfastchargethebattery.
I>
Followtheinstructionsinthe"Battery"chap-
ter.
Vehicle
interior
The
interiormustbedry,especiallyinthearea
ofthefloorcarpets.Theuseofdryingagents
(Silica-Gel)isrecommendedinvehicleswith
leatherinteriorandinareaswithhighhumidity.
Therecommendedamountis3fabricbagsof
1.1Ibs.(500grams)eachplacedonthefloor
carpets.
Windows,doors,lidsandroofmustbeclosed.
Theairflapsshouldbeopened.
Maintenance,CarCare
193

ExerciseExtremeCautionwhen
WorkingonyourVehicle

/!\Warning!
Ignoring
the
followinginstructionsmay
causeseriouspersonalinjury.

[>
Theenginecompartmentofanymotorvehicle
isapotentiallyhazardousarea.Ifyouarenot
fullyfamiliarwithproperrepairprocedures,do
notattempttheadjustmentsdescribedonthe
followingpages.
Thiscautionappliestotheentirevehicle.
[>Onlyworkonyourvehicleoutdoorsorina
wellventilatedarea.
[>Ensurethattherearenoopenflamesinthe
areaofyourvehicleatanytimewhenfuel
fumesmightbepresent.Beespeciallycau-
tiousofsuchdevicessuchashotwater
heaterswhichigniteaflameintermittently.
[>Beforeworkingonanypartintheenginecom-
partment,turntheengineoffandletitcool
downsufficiently.Hotenginecompartment
componentscanburnskinoncontact.
[>Bealertandcautiousaroundengineatall
timeswhiletheengineisrunning.
Ifworkhastobeperformedwiththeengine
running,alwayssettheparkingbrake,and
makesuretheshiftleverisinneutralorthe
selectorleverisinposition"P"or"N".
196PracticalTips,EmergencyService
[>
Inparticular,beverycarefultoensurethat
itemsofclothing(ties,shirt,sleevesetc.),
jewelry,longhair,handorfingerscannotget
caughtintheengine-compartmentblower,
fan,beltsorothermovingparts.
Theradiatorandradiatorfansareinthefront
ofthecar.
Thefanscanstartorcontinuerunningasa
functionoftemperature,evenwiththeengine
switchedoff.
Carryoutworkintheseareasonlywiththe
engineoffandexerciseextremecaution.
[>
YourPorscheisequippedwithanelectronic
ignitionsystem.Whentheignitionison,high
voltageispresentinallwiresconnectedwith
theignitionsystem;therefore,exerciseex-
tremecautionwhenworkingonanypartof
theenginewhiletheignitionisonortheen-
gineisrunning.
[>Alwayssupportyourcarwithsafetystandsif
itisnecessarytoworkunderthecar.The
jacksuppliedwiththecarisnotadequatefor
thispurpose.
[>Whenworkingunderthecarwithoutsafety
standsbutwiththewheelsontheground,
makesurethecarisonlevelground,the
wheelsareblocked,andthattheenginecan-
notbestarted.
Removetheignitionkey.
[>
Donotsmokeorallowanopenflamearound
thebatteryorfuel.
Keepafireextinguisherinclosereach.
[>Incompleteorimproperservicingmaycause
problemsintheoperationofthecar.Ifin
doubtaboutanyservicing,haveitdoneby
yourauthorizedPorschedealer.
Impropermaintenanceduringthewarranty
periodmayaffectyourPorschewarranty
coverage.
[>Suppliesoffluids,e.g.engineoil,brakefluid
orcoolant,arehazardoustoyourhealth.
Keepthesefluidsoutofchildren'sreachand
disposeoftheminaccordancewiththeap-
propriateregulations.
[>Somecountriesrequireadditionaltoolsand
specialsparepartstobecarried.
Pleasemakeenquiriesbeforedrivingabroad.

TiresIWheels
Theoriginalequipmenttiresandwheelrimson
yourPorschecomplywithallapplicableFederal
MotorVehicleSafetyStandards.
Foryoursafetyrememberthefollowing:
-Wheelrimsandwheelboltsarematchedtofit
yourPorsche.
-Ifyouintendtouseotherthanoriginalequip-
mentwheels,besurethattheyconformto
Porschespecificationsforyourmodel.
Onlytireswiththesamemakeandwiththe
samespecificationcode(e.g."NO","Nl"...J
canbemounted.
-Theuseofwheelrimsandwheelboltsthatdo
notmeetspecificationsoftheoriginalfactory
installedequipmentwillaffectthesafeoper-
ationofyourvehicle.
-Beforeyouplanonexchangingwheels,or
snowtiresalreadymountedonthewheel
rims,consultyourauthorizedPorschedealer.
Yourdealerhasthetechnicalinformation
necessarytoadviseyouwhichwheelrimsand
wheelboltsarecompatiblewiththeoriginal
factoryinstallations.
/!\Warning!
Riskoflossofcontrolandseriouspersonal
injury.
t>Ifwhiledriving,yourvehicleexperiencesa
suddenvibrationorridedisturbance,and/or
yoususpectthatpossibledamagetoyour
tiresorvehiclehasoccurred,youshouldim-
mediatelyreduceyourspeedwithoutex-
cessiveuseofthebrakes.
t>Stopthevehicleassoonaspossible,andin-
spectthetires.
Ifyoucannotdeterminethecauseforthedis-
turbance,haveyourvehicletowedtothe
nearestPorscheortiredealertohaveyour
vehicleortire(s)inspected.
t>Continuingtooperatethevehiclewithoutcor-
rectioncouldresultinalossofcontroland
seriouspersonalinjury.
t>t>t>
PracticalTips,EmergencyService
197

Temperature
A,B,C
ThetemperaturegradesareA(thehighest),B
andC,representingthetire'sresistancetothe
generationofheatanditsabilitytodissipate
heatwhentestedundercontrolledconditionson
aspecifiedindoorlaboratorytestwheel.
Sustainedhightemperaturescancausethema-
terialofthetiretodegenerateandreducetire
life,andexcessivetemperaturecanleadtosud-
dentirefailure.
ThegradeCcorrespondstoalevelofperfor-
mancewhichallpassengercartiresmustmeet
undertheFederalMotorVehicleSafetyStandard
No.109.
GradesBandArepresenthigherlevelsofper-
formanceonthelaboratorytestwheelthanthe
minimumrequiredbylaw.
A
Warning!
Thetemperaturegradeforthistireisestab-
lishedforatirethatisproperlyinflatedandnot
overloaded.
Excessivespeed,underinflation,orexcessive
loading,eitherseparatelyorincombination,can
causeheatbuildupandpossibletirefailure.
Tirepressures
A
Warning!
Incorrecttirepressurecausesincreased
tirewearandadverselyaffectsroadhand-
ling.
I>Alwaysuseanaccuratetirepressuregauge
whencheckinginflationpressures.
I>Donotexceedthemaximumtirepressure
listedonthetiresidewall.(Alsoreferto"Tech-
nicaldata").
I>Coldtireinflationpressuremeans:alltires
mustbecold,ambienttemperaturemaximum

68°F
(20°C),whenadjustingtheinflation
pressure.
Avoidsunlightstrikingthetiresbefore
measuringcoldpressures,sincethepress-
ureswouldrisefromtemperatureinfluence.
I>Valvecapsprotectthevalvefromdustand
dirt,andthusfromleakage.
Alwaysscrewcapstightlydown.
Replacemissingcapsimmediately.
I>Forsafetyreasons,don'tusetireinflating
bottles.

Tiretraction

A
Warning!
Whendrivingonwetorslushyroads,a
wedgeofwatermaybuild
up
betweenthe
tiresandtheroad.Thisphenomenonis
knownas"hydroplane"andmaycausepar-
tialorcompletelossoftraction,vehicle
controlorstoppingability.
I>Reducespeedonwetsurfacetopreventthis.

Tirelife

Tirelifedependsonvariousfactors,i.e.,road
surfaces,trafficandweatherconditions,driving
habits,typeoftiresandtirecare.
I>Inspectyourtiresforwearanddamagebe-
foredrivingoff.Ifyounoticeunevenorsub-
stantialwear,wheelsmightneedalignmentor
tiresshouldbebalancedorreplaced.
I>I>I>
PracticalTips,EmergencyService
199

Tire
wear
TheoriginalequipmenttiresonyourPorsche
havebuilt-intirewearindicators.Theyare
moldedintothebottomofthetreadgrooves
andwillappearasapproximately1/2in(12mm)
bandswhenthetiretreaddepthisdownto
1/16ofanin(1.6mm).
Whentheindicatorsappearintwoormoread-
jacentgrooves,itistimetoreplacethetires.
Werecommend,however,thatyoudonotlet
thetiresweardowntothisextent.
Worntirescannotgriptheroadsurfaceproperly
andareevenlesseffectiveonwetroads.
IntheUnitedStates,statelawsmaygovernthe
minimumtreaddepthpermissible.Followall
suchlaws.
200PracticalTips,EmergencyService
/!\Warning!
Drivingonworntirescanresultinlossof
controlofthevehicleandcouldcause
severepersonalinjuries.
~Donotdrivewithworntiresortiresshowing
cutsorbruisesastheymayleadtosudden
deflationandlossofcontrolwhichcould
causeseverepersonalinjury.
~Specializedhighperformancetiresonhigh
performancesportscarsexhibitmorewear
thanthoseonafamilysedan,orevenahigh
performancesedan.
Therefore,itisimportanttocheckyourtire
pressureandconditionatleasteverytwo
weeks.
Ifyounoticethattiresarewearingunevenly,
consultyourPorschedealer.
Unevenwearmaynotalwaysbeduetoim-
properwheelalignment.Itcanbetheresultof
individualdrivinghabitssuchascorneringat
highspeeds.Ifthetirepressureisnotchecked
andadjustedregularly,abnormaltirewearcan
alsooccur.
Tirecare
~Avoiddamagingtiresandwheelrims.
~Ifyoumustdriveoveracurborotherob-
stacle,driveslowlyandatanobtuseangle.
~Checktiresforunevenwearanddamagebe-
foredrivingoff.
~Removeimbeddedmaterial.
~Replacewornordamagedtiresimmediately.
~Keepoil,fuel,brakefluid,etc.awayfrom
tires.
~Replacemissingvalvestemcaps.
~Keeptiresinflatedcorrectly.

Tiredamage,puncture

I>Checktiresforimbeddedmaterial,cuts,punc-
tures,cracksandbulges(sidewall)before
drivingoff.
Incaseoftiredamage,whereitisuncertain
whetherthereisabreakintheplywithallits
consequencesortiredamagecausedbyther-
malormechanicaloverloadingduetolossof
pressureoranyotherpriordamage,werecom-
mendthatthetirebereplacedforsafetyrea-
sons.
Ifonefaultytireisreplaceditshouldbenoted
thatthedifferenceintreaddepthononeaxle
mustnotexceed30%.
Handlinginconsistenciesmayresult.
I>Performavisualinspectionifnecessary.

Tirereplacements

Ifindoubt,contactyourPorschedealeror
PorscheImporterofyourcountry.
Useonlytiremakesandtypestestedby
Porsche.

IfyoudonotuseaPorscherecommended
replacementtire,makesurethatyoupur-
chaseyournewtiresfromareputabletire
dealerandthatthedealercomplieswithall
manufacturerswarningsforthosetires.
Onlytireswiththesamemakeandwiththe
samespecificationcode(e.g."NO","Nl"...)
canbemounted.
Beforemountingnewtires,checkwithyour
Porschedealeraboutthecurrentrelease
status.
Usetireswith"ZR"qualitystandards.
There
arecurrentlynostandardsconcerningtire
strengthatspeedsabove150mph
(240
kmjhJ.
Tiresshouldbereplacednolessthanononeaxleat
thetime.
Onlytiresofthesamemakeandtypemustbeused.
Mixedtiresarenotpermissible.
Initially,newtiresdonothavetheirfulltraction.
Youshouldthereforedriveatmoderatespeeds
duringthefirst
60-120
miles(100-200kmJ.
Ifnewtiresareinstalledonlyononeaxle,ano-
ticeablechangeinhandlingoccursduetothe
differenttreaddepthoftheothertires.
Thishappensespeciallyifonlyreartiresarere-
placed.However,thisconditiondisappearsas
thenewtiresarebrokenin.
I>Pleaseadjustyourdrivingstyleaccordingly.
Installationofnewtiresshouldonlybedoneby
aqualifiedtiretechnician.

Valves

Rubbervalvestemsmustbereplacedevery
timeatireisreplaced.
Forsteelvalves,theinstallationandreplacement
instructionsmustbeobserved.
UseonlygenuinePorschesteelvalves.

Parkingatthecurb
A
Warning!
Hardimpactsagainstcurbs(ortraffic
islands)aredangerousandmaycausehid-
dentiredamagewhichisnotnoticeable
untillater.Suchdamagecanresultinacci-
dentsathighspeedscausingsevereper-
sonalinjury.
Dependingontheforceofimpact,theedge
oftherimcanalso
bedamaged.
I>Ifyouareindoubt,havethewheelchecked
byanexpert,particularlyifyoususpectdam-
ageontheinside.
I>Ifyoumustdriveoveracurborotherob-
stacle,driveslowlyandatanobtuseangle.
Exercisecarewhenparkingalongcurbs.
PracticalTips,EmergencyService
201

Wheelalignment,wheelbalancing

Alsoreferto"Four-Wheeldrive".
Asaprecaution,havewheelswithsummertires
balancedinthespring,andthosewithmudand
snowtiresbeforewinter.
Unbalancedwheelsmayaffectcarhandlingand
tirelife.
Onlythespecifiedweightsmaybeusedfor
wheelbalancing.
Self-adhesiveweightsmustnotcomeintocon-
tactwithcleaningagents,sincetheycoulddrop
off.
Awheelshouldalwaysbebalancedafteratire
repair.
Uneventreadwearindicateswheelimbalance.In
thisevent,thevehicleshouldbecheckedatan
authorizedPorschedealer.
/!\.Warning!
If,duringajourney,unevenrunningorvi-
brationsoccurthatcouldbecausedby
damagetotiresorthecar,thespeedmust
bereducedimmediately,butwithoutbrak-
ingsharply.
Ifyoucontinueyourtripwithouthavingthe
causeofthefaultremedied,youmightlose
controlofyourvehiclewhichcouldcause
severepersonalinjury.
I>Stopthevehicleandcheckthetires.
202PracticalTips,EmergencyService
I>Ifnocauseforthefaultcanbefound,drive
carefullytothenearestauthorizedPorsche
dealer.

Removingandstoringtires

I>Afterchanging,adjusttirepressureand
torquewheelboltsdiagonallyto94ftlb
(130

Nm).
See"Changingwheels".

Tiresmustalwaysremainonthesameside
ofthevehicle.

Whenwheelsareremoved,thedirectionofrota-
tionandpositionofeachwheelshouldbe
marked.
Example
FR(frontright),FL,RRandRL.
Wheelsmustalwaysbefittedinaccordancewith
theirmarking.
Thepreceptionthattiredurabilityandperfor-
manceareimmunetotheeffectsofstorageand
ageisunfounded.
Chemicaladditives,whichmaketherubberelastic,
losetheireffectivenessinthecourseoftimeand
therubberbecomesbrittleandcracks.

Therefore,thetires,especiallythespare
tire,shouldbeinspectedfromtimetotime.
Note

Undernocircumstancesshouldtiresolderthan
6yearsbeusedonyourPorsche.
Theageofthetirecanbeobtainedfromthe
"DOT"codenumber.If,forexample,thelast
threenumbersread1202,thenthetirewaspro-
ducedinthe12thweekof2002.

Storetiresinacoolanddryplace.
Snowtires

Forabettergriponsnowandice,useradialM+S
tireswithstuds.
CheckwithyourlocalMotorVehicleBureaufor
possiblerestricTIons.

/!\.Warning!
Riskoflossofcontrolanddamagetothe
vehicleaswellasseverepersonalinjury.
Thestandardtiresprofileandrubbermix-
tureareoptimizedforwetanddrydriving
conditions,andmaynotprovefavorablefor
snowconditions.

I>ThereforeinstallM+Stiresbeforedrivingin
suchconditions.