1998 HONDA CIVIC MAIN WIRE

Ground-to-Components I ndex
f.,lONOTE: All ground wires are BLK unless otherwise noted.
GroundPageComponents or Circuit Grounded
Battery (BLKYEL)
Steering pump bracket
t+-rg ITransmission housing
l
G101
(-1)
G101
(-2)
14-2
and
14-3
ano
14-1
Powertrain or engine control module (PG1 and pG2 are BLK: LG1 and LG2 are
BRN/BLK), EGR control solenoid valve (CW, EGR valve and lift sensor (Dt6yS enginewith M,/T), Engine coolant temperature switch, pGM-Fl main relay, power steeringpressure switch (USA), Primary HO2S (D16Y5 engine with l\/,/T), Vehicle speed sensor,VTEC pressure switch (D16Y5/D16Y8 engines), CKF sensor (BRN/BLK), Transmission
control module (CYf) (Pc1 is BLK: LG1 is BRN/BLK)
Shielding betvveen the PCM or ECM and these components (all have BRN/BLK wires):
CKF sensor, TDC/CKP/CYP sensor. Primary and secondary heated oxygen sensors.
Knock sensor (CWDl6YB engine), Mainshaft speed sensor (AiT except CVT),
I Countershaft speed sensor (A/T except CVf)
Shielding between the TCM and these components (CVT) (all have BRN/BLK wires):
Drive pulley speed sensor, Driven pulley speed sensor, Secondary gear shaft
speed sensor
Powertrain or engine control module (PG1 and pG2 are BLK; LG1 and LGz are
BRN/BLK), EGR control solenoid valve (D16Y5 engine), EGR valve (Dt685), Engine
coolant temperature switch, Fuel pressure regulator shut-off solenoid valve (D1685),
PGM-FI main relay, Power steering pressure switch (USA), Vehicle speed sensor, VTECpressure switch (All except D16Y7 engine), CKF sensor (A

except 81642) (BRN/BLK)
Shielding between the PCM or ECM and these components (all have BRN/BLK wires):
CKF sensor, TDC/CKP/CYP sensor, Primary and secondary heated oxygen sensors,
Knock sensor (All except D16Y7 engine), i/ainshaft speed sensor (Arf except CW),
Countershaft speed sensor (A,/T except CVf), Drive pulley speed sensor (CW), Drivenpulley speed sensor (CVT), Secondary gear shaft speed sensor (CVf)
I Badiator fan motor, Right front parking/turn signat tight, Right headtight
G20214-4I Cruise control actuator, Left front parking/turn signal lights, Left headlight, Rear window
I washer motor, Windshield washer motor, Washer fluid level switch (,99-'00 Canada)
G401| +-o
and
14-7
Accessory power socket, Brake fluid level switch, Clutch interlock switch (M/T), Clutchswitch (lillT with cruise/D16Y5 engine with MfD, Combination wiper switch (Z wires),
Cruise control main switch, Cruise control unit, Dash lights brightness controller, Data
link connector, Daytime running lights control unit (Canada), Gauge assembly, Horn('96-'97 models), Integrated control unit, Interlock control unit (ArI), Keyless door lock
control unit ('99-'00 models with keyless), Moonroof close and open relays, Moonroof
switch, Park pin switch (A/r), Power window relay, Rear window defogger relay, Rear
window defogger switch ('96-'98 models), Steering lock, Stereo radio tuner (,96-,98
USA: LX, EX, and HX), Turn signal/hazard relay, Windshield wiper motor.....plus
everything grounded through G402
6-6

Ground Distribution
- Gl01 ('98 Dl685;All '99-'00 models except D16YS with M/T)
NOTE: Wires shown without color codes are black.
01685/_ D16Y5/ -.016Y8engrnes
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, wEc: PRESSURE '
, swtTcH :I Page24-4 iI PHOTO 150: r -'l
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FUELPRESSUREREGULATOR ENGINESHUT.OFF COOLANTSOLENOID TEMPERATUREVALVE SWTTCHPage 25-1 Page 63PHOIO 143 PHOTA 33r-1F-.|
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POWERTRAIN olENGINE CONTROLMODULE (PCM or ECM)Page 24-3 ot 25-3PHOTO 86
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PGi,|.FIMAINRELAYPage 24ol 25
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excaptD1685
VEHICLESPEEDSENSOR(vss)Page 336FN/ELKERll/EIKcl01PHOTO 21PHOTO 142(o1685)vtEw 28
ct16Cferml-nals8n 4)
FltaFt( vttw 39t- .''iiti ' " D1685/D16Y5 engrnes ---'
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. ENGINE : :
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14-2
o-----J

cRutsECONTROLMAINswrTcHPage 34
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. - -' accessory
: security system :
i secun,rY ;
: SYSTEMi coNNEcroR :' (oPTroN)' Page |33
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ili; . ----+
REARWINDOW DASH LIGHTSDEFOGGER BBIGHTNESSSWITCH CONTROLLER
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'96-'98 modelspr+wi.ed tor
'99'00 modelspre-wired lor-_----accessory, security system
I srcunrw sEcunrrY :, SYSTEM SYSTEM ;i CONNECTOR CONi{ECTOR '' (oPTroN)
: Page 133-4
PHO|O136'
I- ABS -.
.-- USA: LX. -' .-' vo-Jl --', EX, and ilx mooers
vtEw 56
MOONROOF
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'iii?,;) i??3;?'
' STEREO' RADTO TUNER ' ' DASH LIGHTS ,' P.da11o-, ' ' BRIGHTNESS '', ,;;;;- - : : coNTRoLLER '', v,iw;;" i i eage tte.t :, r-1 ,r r-1
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MOON-ROOFOPENRELAYPage 122ot 122-1
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14-7

Gruise Control (cont'd)
- How the Circuit Works
The cruise control system uses mechanical and
electrical devices to maintain the car's sDeed at a
setting selected by the driver.
System Description
The cruise control unit receives command signals
from the crurse control main switch and the cruise
control SeVResume switch. With the ignition switch
in ON (ll) or START (lll), voltage is provided to the
cruise control main switch through fuse 14. When
you push the switch to ON, power is provided to the
cruise control unit and the brake switch.
The cruise control unit receives information about
operating conditions from the brake switch, the
vehicle speed sensor (VSS), and the clutch switch
(manual transmission) or the A,/T gear position
switch (automatic transmission). The cruise control
unit then sends signals to the cruise control actuator
which regulates the throttle position to maintain the
selected speed. The conlrol unit compares the
actual speed of the car to the selected speed. The
control unit then uses the result of that comoarison
to open or close the throttle.
The brake switch releases the system's control of
the throttle at the instant you press on the brake
pedal. The switch sends a signal to the control unit
by removing power from the normally closed brake
input (GRY wire), and providing power at the
normally open brake input (GRN/vVHT wire). The
control unit responds by allowing the throttle to
close. The clutch switch or the A,/T gear position
switch sends a "disengage" signal to the control unit
that also allows the throttle to close.
The cruise control system will set and automatically
maintain any speed above 25 mph (40 km/h). To set
it, make sure the main switch is on and the switch
indicator is on. Then, after reaching the desired
speed, press the SET switch. This sends a "set"
signal to the cruise control unit which, in turn,
controls the cruise control actuator to maintain the
set speed.
When you push the SET switch and the cruise
control system is on, the "cruise control" ON
indicator lights up.
34-4
(
You can cancel the cruise control system by
turning the main switch off . This removes power to
the control unit and erases the set speed from
memory. lf the system is disengaged temporarily
by the brake switch, or clutch switch, and the car's
speed is still above 25 mph, press the resume
switch: the car will automatically return to the
previously set speed.
For gradual acceleration without pressing the
accelerator pedal, push the RESUME switch and
hold it there. This will send an "acceleration" signal
to the control unit. When you release the switch, the
system will be reprogrammed for the new speed. To
slow the car down. oush the SET switch in and hold
it there. This sends a "deceleration" signal to the
control unit, causing the car to coast. When the
desired speed is reached, release the SET switch.
This reprograms the system tor the new speed.
Refer to the Service Manual (Section 23, Electrical)
tor specific tests or troubleshooting procedures.
(
a

Headlights (cont'd)
- How the Circuit Works
Low Beams
With the headlight switch in HEAD and the dimmer
switch in LO, current tlows through the headlight
switch. fuse 21 . fuse 22. and the low beam
tilaments to ground, and the low beams come on.
High Beams
With the headlight switch in HEAD and the dimmer
switch in Hl, current flows through the headlight
switch, dimmer switch, fuses 4, 5, and the high
beam filaments to ground, and the high beams
come on.
Current also llows through the high beam indicator
light to ground. The high beam indicator comes on
to remind the driver that the high beams are on.
Flash-to-Pass
The flash feature works with the headlight switch in
OFF, PARK, or HEAD (low beams). When you move
the flash-to-pass switch to ON, current flows
through the switch, fuses 4 and 5, and the high
beam filaments to ground, and the high beams
flash. The high beam indicator also flashes during
the flash operation. The flash function has no effect
if the high beams are already on
Daytime Running Lights (Canada)
When you turn the ignition to ON (ll) with the
parking brake released, the daytime running lights
control unit supplies battery voltage at the
WHT/RED wire. This voltage is applied to the high
beam headlights through the daytime running lights
resistor. Each high beam headlight receives less
than battery voltage causing them to come on at
reduced brightness.
lf the parking brake is set, a ground signal is applied
to the daytime running lights control unit at the
RED/GRN wire. lf the parking brake is set when you
first turn the ignition switch to ON (ll), the high beam
headlights will remain off until you release the
parking brake. Once the high beam headlights are
on, setting the parking brake will not turn them ofi.
When low or high beam operation is requested,
battery voltage from the headlight switch is applied
to the daytime running light control unit via the RED
wire. The daytime running lights control unit then
turns off the headlights.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or lroubleshootrng procedures.
110-14

Power Door Locks (cont'd)
- How the Circuit Works
Keyless Entry System
The keyless door locks combine the power door
locks with a remote keyJob transmitter. The keyless
receiver unit is part of the radio. The keyless
receiver unit receives direct inputs f rom the ignition
key switch, the passenger door switches, and an
indirect input trom the driver's door switch through
the integrated control unit.
Power Door Locks (With or Wlthout Keyless)
The power door lock system is made up of the
oower door lock control unit. driver's door lock
switch, and individual door lock actuators. The
power door locks are controlled by the driver's door
lock switch and the driver's door lock actuator
switch.
Transmitter (With Keyless Entry)
The transmitter sends coded radio wave signals to
the keyless receiver unit when one ot its buttons is
pressed. Each transmitter has a unique code that
must be 'laught" to the keyless receiver unit before
it can operate the door locks or any other lunction.
Up to 4 transmitters can be programmed to operate
the keyless door locks.
Door Locking (With or without Keyless Entry)
When you push the driver's door lock switch to the
lock position, ground is applied to the GBN/IVHT
wire to the oower door lock control unit. The control
unit then applies battery voltage to the WHT/RED
wire and ground to the YEURED wire. The
passenger door lock actuators then activate to lock
the corresponding door locks.
When you lock the driver's door with the key or door
lock knob, it is mechanically locked, and the driver's
door lock actuator switch applies ground to the
oower door lock control unit. The control unit then
applies battery voltage to the WHT/RED wire and
ground to the YEURED wire, activating the
passenger door lock actuators which lock the doors.
Dool Locking with Transmitter
When you press the LOCK button on the remote
transmitter, the power door lock control unit applies
battery voltage to the WHT/RED wire and ground to
the YEURED wire. The passenger door lock
actuators then activate and lock the doors. A ground
slgnal is also applied to the BLU/RED wire to lock
the driver's door. lf any door is open, you cannot lock
it using the remote transmitter.
Door Unlocking (With or Without Keyless Entry)
When you push the driver's power door lock switch
to the unlock position, ground is applied to the
GRN/ORN wire to the power door lock control unit.
The control unit then applies battery voltage to the
YEURED and BLU/RED wires and ground to the
WHT/RED wire. The door lock actuators then
activate to unlock the doors.
When you unlock the driver's door with the key or
the door lock knob, it is mechanically unlocked; the
other doors do not unlock.
Door Unlocking (With Transmltter)
When you press the UNLOCK button on lhe remote
transmitter once. the power door lock control unit
applies battery voltage to the WHT/RED wire and
ground to the BLU/RED wire to unlock the driver's
door. When you press the UNLOCK button twice,
the control unit then applies ground to the YEURED
wires to activate the passenger door locks. lf you do
not open a door within 30 seconds after unlocking
the doors with the transmitter, the doors
automatically relock.
Transmltter Programming
1 . Turn the ignition switch ON (ll).
2. Press and hold the Valet-Disarm button on the
radio (between the AM/FM button and the
CD/TAPE button) to enter the programming
mode. (Continue to hold the button during the
procedure, or programming will be cancelled.)
Check that the power door locks cycle to confirm
that you're in the programming mode.
3. Press the "LOCK' or "UNLOCK' button on the
transmitter. Check that the power door locks
cycle to confirm that the code was accepted.
4. Press the "LOCK" or "UNLOCK" button on each
of the remaining transmitters. (You can program
up to four transmitters per vehicle.)
5. After all the transmitters have been
programmed, release lhe Valet-Disarm button to
exit the programming mode.
Beep On/Oft Feature
'I . Press and hold the LOCK and OPTION buttons
on the transmitter.
2. Watch the transmitter's LED:
One flash: Beeo activated.
Two tlashes: Beeo deactivated.
130-4

Power Door Locks (cont'd)
Keyless Receiver Unit Input Test
The following tests are pertormed with A (Main) and B (Keyless) disconnected from the audio unit.
TerminalNo.WireColorTest ConditlonTest: Desired RasultPossible Cause it resull is not obtained
4WHT/BLUUnder all conditionsCheck for vollage to ground:
There should bs batteryvoltage.
aBlown No. 47 (7.5A) tuse in the
under-hood fuss/relay box
An open in the wireo
5YEUREDlgnition switch ACC (l)Check lor voltage to ground:
Th€re should be battery
voltage.
aBlown No. 28 (10A) fuse in the
underdash fusg/relay box
An open in the wirea
TerminalNo.WireColorTest CondiiionTest: Desired ResultPossible Cause if rssult i3 not obtalned
BLU/RED
lgnition key insertedinto the ignition key
switch
Check for voltage to ground:
There should bs 1 V or less.aPoor ground (G401, G402)
Faulty ignition key switch
An open in the wire
Short in the wire
a
a
algnition key r€moved
trom the ignition key
switch
Check lor voltage to ground:
There should be 4 V or more.
3BLUI/ELUnder all conditions
Check for continuity betweenthe audio unit 16P connectorNo- 3 terminal and power doorlock control unit 12P connsctorNo. 6 terminal: There should
be continuity.
I An open in the wire
6BLK/YELlgnition switch ON (ll)Check for voltage to ground:
Thers should be batteryvollage.
. Blown No. 14 (7.5A) fuse in the
under-dash fuse/relay box
. An open in the wire
8LT GRN/BLKCeiljng light switch in"middle position"Connect to ground: The ceilinglight should come on.
aBlown No. 43 (7.5A) fuse in the
undsr-hood fuse/relay box
Blown ceiling light bulb
Faulty ceiling light
An open in the wire
a
a
o
14LT GRN/REDEach door oponed,one at a timeCheck for continuity to ground:
There should be continuity.
aFaulty door switch
An open in lhe wirea
tcBLKUnder all conditionsCheck for continuity to ground:
There should b€ continuity.
aPoor ground (G401, G402)
An open in the wirea
16GRYUnder all conditionsConn€ct to ground:
Horn should sound.
. Blown No.52 (15A) fuse in the
under-hood tuse/relay box
. Faulty horn
. Faulty horn relay
. An open in the wire
130-6

\
The following tests are performed with A (Main) reconnected to the audio unit.
B
\
TerminalNo.WireColorTest CondilionTest: Desired ResultPossible Cause it result is not obtained
9GRN/ORN
Driver's door lockswitch in UNLOCKCheck tor voltage to ground:There should be l V or less.
o Poor ground (G551)
. Faulty driver's door lock switch
. An open in the wire
. Short in the wire
Driver door lockswitch in LOCKCheck for voltage to ground:
There should be 4 V or more.
10GRN/vvHT
Driver's door lockswitch in UNLOCKCheck for voltage to ground:
There should be 4 V or more.
r Poor ground (G551)
. Faulty driver's door lock switch
o An open in the wire
o Short in the wire
Driver's door lockswitch in LOCKCheck for voltage to ground:
There should be 1 V or less.
\
130-7