Keyless/Power Door Lock System
Control Unit Input Test (cont'dl
5. Reconnect all connections to the underdash fuse/relay box, and make these input tests at the appropriate connectors on the under-dashfuse/relay box.
'lfanytestindicatesaproblem,findandcorrectthecause,thenrecheckthesystem.. lf all the inputtests prove OK, goto step 6.
CavitvWireTest conditionTest: Desired resultPossible ca use if result is notobtainedc1'l8LUUnder all conditionsAftach to ground:Parking, side marker, licenseplate lights, and tajllights shouldcome on.
Blown No.2 (15A)fuse in the underhood fuse/relay boxFaulty taillight relayFaulty under-dash fuse/relay boxAn onen in rhc wireBLU/BEOUnder all conditionsAttach to ground:Headlights should come on.Blown No. 15 or 17 (15A)fuse in theunderhood fuse/relay boxFaulty headlight relay '1 or 2An ooen in the wireJ2WHT/REDUnder all conditionsCheck for voltage to ground:There should be battery voltage.Blown No.9 (15A)fuse in the under-hood fuse/relay boxAn oncn in thc wircBLKUnder all conditaonsCheck for voltage to ground:Thcre shouln hc 1 V or lpqsPoor ground (G501)An ooen in the wireJ6OBNUnder allconditionsAttach to ground:The horns should sound.Blown No. 7 (15A)fuse in the underhood fuse/relay boxFaulty horn relayFaulty hornsAn 6nen in rhe wireJ7Under all conditionsCheck for voltage to ground:There should be battery voltage.Elown No. 16 (20A)fuse in the underhood fuse/relay boxAn oocn in ihc wi.cP18BEDHatch openCheck for voltage to ground:There should be 1 V or less.Poor ground (G552)Faulty hatch latch switchAn oncn in rhc wirFHatch closedCheck for voltage to groundlThere shoul.l he 5 V or moreFaulty hatch latch switch
GBNDriver's door openCheck for voltage to g.ound:There should be 1 V or less. Faulty driver's door switch. An ooen in the wireDriver's door closedCheck for voltage to ground:There should be 5 V or more.Faulty driver's door switchShort to oroundo4LT GRN/REDPassenger's door openCheck for voltage to ground:There should be 1 V or less.Faulty passenger's door switchAn ooen inthewirePassenger's door closedCheck for voltage to groundlThere should be sVor more
. Faulty passenger's door switch. Short to oroundX5REDAVHTlgnition key inserted intothe ignition swhchCheck for voltage to ground:There should be 1 V or less.Poor ground {G401)Faulty ignition key switchAn ooen inthewirelgnition key removed fromrhe ionition switchCheck for voltage to ground:There should be 5 V or more.Faulty ignition key switchShort to oroundY1WHT/BLKDriver's door lock knobswitch unlockedCheck for voltage to groundlThere should be 1 V or less.Poorground (G50'l)Faulty driver's door lock knob switchAn open in the wireDriver's door lock knobCheck for voltage to groundlIhere should be 5 V or more.Faulty driver's door lock knob switchShort to oroundY8YEUREDDriver's door lock knobswitch lockedCheck for voltage to groundlThere should be 1 V or less.Poorground (G50'l)Faulty driver's door lock knob switchAn oncn inihewireDriver's door lock knobswitch unlockedCheck for voltage to ground:There should be 5Vor more' Faulty driver's door lock knob sw;tch. Shorr to oroundY10WHT/GRNDrtver's door lock switchunlockedCheck for voltage to groundlThere should be 1 V or less.Poorground (G501iFaulty driver's door lock switchAn ooen in the wireDriver's door lock switch inCheck for voltage to ground:Therc shorl.l be 5V or m6rpFaulty driver's door lock switchShort to o rolrndY12WHT/BLUDriver's door lock switchlockedCheck for voltage to ground:There should be 'l V or less.Poor ground (G501)Faulty driver's door lock switchAn oDen in the wireDriver's door lock switch inCheck tor voltage to ground:There should be 5Vor moreFaulty driver's door lock switch
22-156
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ISystem Descriptions
The Multiplex Control System has four internal
functions:. Multiplexing (send multiple signals over sharedwtres). Wake up/sleep (runs at full power only on demand toreduce battery draw). Fail-safe (fixes or ignores faulty signals). Self-diagnosis (Mode 1 for the system, Mode 2 for
input lines)
The system controls the function of these circuits:. Entry lightcontrol (ignition key lightandceiting light). Wiper/washer intermittent wipe and park functions. Keyless/power door lock. Meter assembly, temperature gauge, and indicator
lights. HVAC (compressor and fan control). Key-in reminder. Headlight reminder. Seatbelt reminder
JI
/ar
22-171
Multiplex Communication
To reduce the number of wire harnesses, digital signals
are sent via shared multiplex communication linesrather than sending normal electrical signals throughindividual wires.. The input signals from each switch are converted todigital signals at the central processing unit (CpU).. The digital signalsaresentfromthetransmitting unitto the receiving unit as serial signals.. The transmitted signal is converted to a switch signalat the receiving unit, and it operates the related
component or monitors a swltch.. There are exclusive communicalion lines between
the ECM, the gauge assembly, and the under,dash
fuse/relay box.
Wake-up and Sleep
The multiplex control system has "wake-up" and"sleep" functions to decrease parasitic draw on the
battery when the ignition switch is OFF.. ln the sleep mode, the multiplex control unit stops
functioning (communication and CPU control) when it
is not necessary for the system to operate.. As soon as any operation is requested (for example, adoor is unlocked), the related control unit in the sleep
mode immediately wakes up and begins to function.. When the ignition switch is turned OFF, and the
driver's or front passenger's door is opened, then
closed, there is about a 10 second delay before the
control unit goes from the wake-up mode to the sleepmode.. lf any door is open, the sleep mode will not function.. lf a key is in the ignition switch, the sleep mode will
not function.. When in sleep mode, the draw is reduced from
70 80 mA to less than 10 mA.
Fail-safe
To prevent improper operation, the multiplex controlsystem has a fail-safe function. In the fail-safe mode,
the output signal js fixed when any part of the systemmalfunctions (for example a faulty control unit orcommunication line).
Each control unit has a hardware fail-safe function thatfixes the output signal when there is any CPUmalfunction, and a software fail-safe function thatignores the signal from the malfunctioning control unitand allows the system to operate normally.
Service Manual Index
(cont'dl
Brake System Indicator CircuitCircuit DiagramConventional Brake Components..... 19-9TroubleshootingABS/TCS Components .... ....... ...... 19-55
Bulb, GeugeRep|acemenl................ .. ............2263
Bulb, HeadlightReplacement ......................................... 22-A1
Bumper, FrontRemoval/1nsra11ation ............................ 20 85
Bumper, RearRemoval/lnstallation... ... . .....20.86
Combination Light SwilchTesVReplacement ..............................22 80
Connecting Rod BearingsRep|acement...................... .......-....7-8
Connecting Rod Boltsf nspection ....................-.-.-.-.................... 7 -24
Connecting RodsInspection ........,,.,.,...,.,.,.,.,,,,.,,,.,.,.,.,.,.,.,.. 7 5
Connectors(See first page of this Index)
Conventional Brake Component3Component Location Index ................... 19'3Troub1eshootin9 ..................................... 19-4
Cylinder Head AssemblyComponent Location Index ..................... 6-3Inspection ................................................. 6 6Removal ..........&