engine coolant temperature sensor HONDA CIVIC 1999 6.G Owner's Guide

Connector ldentification and Wire Harness Routing
Engine Wire Harness {Dt6Y7 enginel: '97 - 9g models
Connectot or
Terminal
Number of
CsvitiesLocationConnects toNotes
c 101
c102
c103
c104
c104
c105
c106
c107
c 108
c109
cl10
clll
c112
cl13
cl14
c115
c1 l6
c117
c118
cl 19
cl20
c121
c122
c123
cl24
c124
c125
c126
c127
c128
c129
c 130
c 131
c132
c134
c135
cl41
10
1
2
10
I
2
2'>
4
t
20
3r
2
No. l fuel injector
No.2 fuel injector
No. 3 fuel injector INo. 4 fuel injector
IAC valve ]Throttle position (TP) sensor IManifold absolute pressure (MAP) sensorIntake air temperature (lAT) sensor ]Power steering pressure (PSp) switch I USAEVAP purge control solenoid valve
Junction connector IJunction connector IVehicle speed sensor (VSS)
Countershaft speed sensor I enEngine coolant temperature (ECTI
Main wire harness (C303)
Crankshaft speed fluctuation (CKF)
sensor
Engine oil pressure switch
Alte|'nator
Alternator
switch A
Distributor
Engine coolant temperature (ECT)
sending unit
Engine coolant temperature (ECT) sensor
Primary HO2S (sensor 1)
Back-up light switch
Lock-up control solenoid valve
Secondary H02S (sensor 2)
Mainshaft speed sensor
Linear solenoid valve
Shift control solenoid valve
Staner solenoid
Junction connector
Main wire harness (C446)
Left side of engine compartment
Middle of engine
Middle of engine
Left side of engine compartment
Left side of engine compartment
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Left side of engine compartment
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Right side of engine compartment
Behind right kick panel
Under right side of dash
Under right side of dash
Under right side of dash
Under right side of dash
Under right side of dash
Left side of engine compartment
Middle of engine
USA
Canada
Mtr
AIT
ECM/PCM
PcM I ArrECM/PCM
ECM/PCM
Main wire harness {C305) | AftEVAP control canister vent shut valve
T 101
r102
Left side of engine compartment
Right side of engine companment
Alternator
Under-hood fuse/relay box
G 101Middle of engineEngine ground, via engine wire harness
23-22

Connector ldentification and WireHarness Routing
Engine Wire Harness (D15Y? engine): ,99 - OO models
c101
c102
cl03
c't04
c 104
c 105
cr 06
0107
c108
c109
c't 10
c11 r
c112
c113
c114
c115
c116
c117
cl18
c119
c120
c121
c122
c123
c124
c124
c125
c127
c128
c129
c 130
c 131
c134
c135
10
3
'I
3
?
2
3?
2
14
14
3
2
8
1
Left side of engine compartment
Middle of engine
fvliddle of engine
Left side of engine compartment
Left side of engine companment
Middle of engine
Middle of engine
Middlr ol sngins
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Right side of engine compartment
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Right side ot engine compartment
Behind right kick panel
Under right side of dashBehind right kick panel
Behind right kick panel
Behind right kick panel
Main wire harness (C303)
Crankshaft speed fluctuation (CKF)
sensor
Engine oil pressure switch
Alternator
AlternatOr
No. l fuel injector
No.2 fuel injector
No. I fual itjecto,
No.4 fuel injector
IAC valve
Throttle position (TP) sensor
Manifold absolute pressure {MAp) sensorIntake air temperature 0AT) sensorPower steering pressure (PSp) switchEVAP purge control solenoid valveJunction connector
Junction connector
Vehicle speed sensor (VSS)
Countershaft speed sensor
Engine coolant temperature {ECT)switch A
Distributor
Engine coolant temperature (ECT)
sending unit
Engine coolant temperature (ECT) sensor
Primary HO2S (sensor 1)
Back-up light switch
Lock-up control solenoid valveSecondary HO2S (sensor 2)Mainshaft speed sensor
Linear solenoid valve
Shift control solenoid valve
Starter solenoid
Junction Connector
Main wire harness (C446)
ECM/PCM
ECM/PCM
PCM
USA
Canada
M/T
Atr
Atr
Alr
Al-|.
Left side of engine compartment
Right side of engine compartment
Middle of engineEngine ground, via engine wire harness
23-24

Connector ldentification and WireHarness Routing
Engine Wire Harness {81642 engine}: .99 - 00 models
c 101
c102
cl03
c104
c 104
c'105
c106
cl01
c108
c110
cl11
cl12
c1'13
c114
c115
c117
cl19
c120
c121
c122
c123
c124
c129
c130
c l31
c133
c134
c137
c 138
c139
c140
Left side of engine companment
Middle of engine
Middle of engine
Left side of engine compartment
Left side of engine compartmentlvliddle of engine
Middle ot engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle ot engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine
Middle of engine compartment
Middle of engine
Middle of engine
Middle of engine
lMiddle of engine
Middle of engine
Middle of engine
Right side of engine compartment
Behind right kick panel
Under right side of dash
Behind right kick panel
Behind right kick panel
Middle of engine
Middle ot engine
lMiddle of engine
Middle of engine
10
2
,]
4
3
2
2
2
2
3
3
2
2
2
14
14
3
2
'10
'I
2
4
2
1
20
22
25
31
2
2
I
Main wire harness (C303)
Crankshaft speed fluctuation (CKF)
sensor
Engine oil pressure switch
Alternator
Alternator
No. 1 fuel injector
No. 2 tuel injector
No. 3 fuel injector
No. 4 fuel injector
Throttle position (TP) sensor
Manifold absolute pressure (MAP) sensorIntake air temperature (lAT) sensorPower steering pressure (PSP) swjtchEVAP purge control solenoid valve
Junction connector
Junction connector
Vehicle speed sensor (VSS)
Engine coolant temperature (ECT)
switch A
Distributor
Engine coolant temperature (ECT)
sending unit
Engine coolant temperature {ECT) sensorPrimary HO2S (sensor 1)
Back-up light switch
Starter solenoid
Junction connector
Main wire harness (C446)
ECM
ECtvl
Knock Sensor {KS)IAC valve
VTEC solenoid valve
VTEC pressure switch
USA
Canada
Left side of engine companment
Right side of engine compartment
Engine ground, via engine wire harness

JGau ge/lndicator/Terminal
With tachometer;
CONNECTOR "A"
{A/T GEAR POSITION INDICATOR}
Location lndex
CONNECTOR "8"
{GAUGE and INOICATOR)CONNECTOB "C"
CONNECTOR "D"
{ABS INDICATORI
SPEEDOMETER:Indicates 60 km/h at 637 rpm or
60 mph at 1,025 rpm o{thevehicle speed sensor (VSS).
A/T GEAR POSITIONINDICATORSee page 23 149
TACHOMETER:Indicates 100 rpm at200 pulses per minuteol the ignition controlmodule (lCMi.FUEL GAUGEENGINE COOLANT TEMPERATURE (ECT) GAUGE
(cont'd)
23-129
(GAUGE end INDICATORI
A1-----------+816
JlltlllulllllrL
c1 --------->c13
1ililil{ilrL
oooo o 0006^
)og @ @ o^o @ )'l |. o
Fl- - -> F5E1_ _ -->E5D1- --+05
oo/ \oo
Gauge/Sending Unit Test, page 23-142

Contents
How to Use This Manual ICircuit Schematics (see Circuit Index)Fuse/Relaylnformation 6Ground-to-Componentslndex 6-6ComponentLocationPhotooraohs 201Conriector Views 202
Circuit Index
Accessory power socket 155Air conditionerAir delivery'96198 models 61'99-'00 models 61-2Blower controls'96198 models 60'99100 models 60-1Compressor controls 62Fans 63Anti-lock brake system (ABS) 44A/T gear position indicatorCVT 89All except CVT 89-1Automatic transmission controlsAll '96-'98 models except CVT and GX 39All '99100 models except CVT 39-8All GX models 39-8'96-'98 CVT 39-4'99100 cw 39-12Back-up lightsCoupe and Sedan 110Hatchback l'10-1Brake lightsAll Coupes and'96-'98 Sedans 110-15'99-'00 Sedans 110-16Hatchback 110-17Brake system indicator light'96198 models 7'1'99100 models 71-1Ceiling light 114-3Charging system 22Condenser fan 63Console lights 114Cruise control 34Dash lights 114Daytime running lights 110- 13Engine coolant temperature gauge 81-1Fog lights 110-10Front parking lights 110-2Fuel gauge 81-1Fuse/relay boxUnder-dash 6Under-hood 6-4Underhood ABS 6-3Gauges 81Ground distribution 14Ground-to-Componentslndex 6-6Hazard warning lightsAll except '99100 Sedans 110-6'99100 Sedans 110-8Headlights 110-12Headlight switch 100Heater - See Air ConditionerHorn'96197 models 40'98 model 40-1'99100 models 40-2lgnition key reminder 73lgnition systemAll '96198 models except Dl685 20All '99100 models except D16Y5 with Mn 2O-2All D1685 engines 20-2'99-'00 D 16Y5 with M/T 20
lndicators 80Integrated control unit 70lnterlock systemAll except'96J98 CVT 138'96198CVT 138-1License plate lightsAll Coupes and '96-'98 Sedans I l0-3'99100 Sedans 1 10-4Hatchback 110-5Low fuel indicator light 74Moonrool'96197 models |22'98-'00 models 122-1Odometer 81Oil pressure indicator light 80-3Power distributionBattery to ignition switch, fuses, and relaysFuses to relays and components 10-2Power door locksAll models without keyless entry 130'96-'98 models with keyless entry 130-2'99100 models with keyless entry 130-12Power mirrorsWithout detogger 141With defogger '141-2
Power windows 120Programmed fuel injection system (PGNr-Fl)All '96-98 models except D1685 23All '99-'00 models except D16Y5with M/T and D1685 24All D1685 engines 25'99100 D16Y5 with M/T 23Radiator fan 63Rear window defogger'96-,98 models 64'99100 models 64-1Seat belt reminder 73Security system'96.'98 USA HX, LX, EX 133'96-'98 Canada EX, Si 133'99TOO USA HX, LX, EX, DX.V Si 133-4'99100 Canada EX, Si 133-4All CX and DX models 133-8Speedometer 81Starting systemA./T (All except Dl685) 21A"/r (D16Bs) 21-1Manualtransmission 21-2Slereo sound system 150Supplemental rastraint system (SRS) 47Tachometer 81TailliqhtsAllboupes and'96-'98 Sedans 110-3'99100 Sedans 1 10-4Hatchback 110-5Trunk light 114-3Turn signal lightsAll except'99100 Sedans 110-6'99-'00 Sedans 1 10-8Vehicle speed sensor (VSS) 33Wiper/washerFront 91Rear 92
10

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
.__-;,#'-_,--', engrne ;
, wEc: PRESSURE '
, swtTcH :I Page24-4 iI PHOTO 150: r -'l
:t | :
:l | :,L-J.
FUELPRESSUREREGULATOR ENGINESHUT.OFF COOLANTSOLENOID TEMPERATUREVALVE SWTTCHPage 25-1 Page 63PHOIO 143 PHOTA 33r-1F-.|
llll
lltlL-J L-J
POWERTRAIN olENGINE CONTROLMODULE (PCM or ECM)Page 24-3 ot 25-3PHOTO 86
----:y4
tl
tl
PGi,|.FIMAINRELAYPage 24ol 25
vlEw 18
tl
tl
3Y'I'I
excaptD1685
VEHICLESPEEDSENSOR(vss)Page 336FN/ELKERll/EIKcl01PHOTO 21PHOTO 142(o1685)vtEw 28
ct16Cferml-nals8n 4)
FltaFt( vttw 39t- .''iiti ' " D1685/D16Y5 engrnes ---'
t2
. ENGINE : :
i 933'?il-; i 5"T,Yf,*' 33i,"o, i
i lgfft" i I S.ir1".l^ soL€NorD :' Pase 63 : : ;;;;; - pase 24.i :' PHOTO 63 | | VtEWlO pHOIa124 ;, r-1 | , F-.t r-.r
:l | ;:l | ! | :;t | :,t | | | ;
j,f
ii T.__.,|,,,,,.
j
--
----- --l i otoas I Dr6y5 :
:------.1.--------.
14-2
o-----J

-.t POWERTRAIN
lcoNTRoL
Fuel I MODULE
\. . -,.^-- p{sssure
I llglllTP-. . sansor sensor .s€nsor i;ir*,o; sensor_rnpul input input input :I nFa (PF2) GcD i|An IrL------ --------Jc13 I' c14Y c26
FUELTEMPERATURESENSOR
Fromfacingpage.
v
!
_l
Fromnenpage.
vi
GFN/BLK lI
i
EG-f
flltur'ffi
,{J
ENGINECOOLANTTEMPERATURE(Ecr)SENSOR
INTAKEAIRTEMPERATURE(rAr)SENSOR
c't 15(ferminals &14)
vtEw 38
(cont'd)
25-7

Gauges (cont'd)
- How the Gircuit Works
When the ignition switch is in ON (ll) or START (lll),
battery voltage is supplied through fuse 25 to the
gauges in the gauge assembly.
Speedometer and Odometer
The odometer and soeedometer drive circuits
receive pulses from the vehicle speed sensor
(VSS). The pulse rate increases as the car
accelerates. The frequency and duration of these
input pulses are measured and displayed by the
speedometer, odometer and tripmeter.
Tachometer
The tachometer drive circuit receives pulses from
the ignition control module (lCM) in the distributor
assembly or the ECM/PCM. The solid-state
lachometer then displays these pulses as engine
speed. For each 200 pulses per minute from the
ignition control modul€ (lCM) or the ECM/PCM, the
tachometer displays 100 RPM.
Engine Coolant Temperature Gauge
The engine coolant temperature gauge has two
intersecting coils wound around a permanent
magnet rotor. Voltage applied to the coils, through
fuse 25, generates a magnetic lield. The magnetic
field, controlled by the coolant temperature sending
unit, causes the rotor to rotate and the gauge
needle to move. As the resistance in the sending
unit varies, current through the gauge coils
changes. The gauge needle moves toward the coil
with the strongest magnetic field.
The 6ngine coolant temperature sending unit's
resistance varies from about 137 ohms at low
engine temperature to between 3H6 ohms at high
temperature (radiator fan running).
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
81-2
(
Fuel Gauge (All except cX)
The fuel gauge has two intersecting coils wound
around a permanent magnet rotor. Voltage applied
to the coils, through tuse 25, generates a magnetic
field. The magnetic field, controlled by the fuel
gauge sending unit, causes the rotor to rotate and
the gauge needle to move. As the resislance in the
sending unit varies, current through the gauge coils
changes. The gauge needle moves toward the coil
with the strongest magnetic field.
The fuel gauge sending unit's resistance varies
from about 2-5 ohms at full, to about 110 ohms at
empty. When you turn the ignition switch off, the
gauge remains at the last reading until you turn the
ignition switch to ON (ll) or START (lll) again,
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
Fuel Gauge (GX)
The fuel gauge has two intersecting coils wound
around a permanent magnet rotor. Voltage applied
to the coils, through fuse 25, generates a magnetic
field. The magnetic field, controlled by the PCM,
causes the rotor to rotate and the gauge needle to
move. The PCM calculates the gas quantity in the
fuel tank by using the fuel pressure value detected
by the tuel tank pressure sensor and the fuel
temperature value detected by the fuel tank
temperalure sensor, and outputs the signal to the
gauge assembly. The gauge needle moves toward
the coil with the strongest magnetic field.
When you turn the ignition switch off , the gauge
remains at the last reading until you turn the ignition
switch to ON (ll) or START (lll) again. When the
PCM detects a malfunction with the fuel pressure or
temperature, or detects a gas leak, the PCM
reduces the fuel meter to 0.
Refer to the Service Manual GX Supplement
(Section 11 , Fuel and Emissions) for specific tests
or troubleshooting procedures.
a
a

Connector Views (conrd)
71. Gauge Assembly
- Left side of dash
Connector A (A/T only)
- Green- On dashboard wire harness
1 YEL (lgnition input)
2 RED/BLK (Headlight
switch ON input)
3 RED(Dash light brightnesscontroller input)
4 BLU (L or 2indicator control)
6 D16Y7/D16Y8:BRN (Not used)
8 BLK (G401)
Connector B
- Blue- On dashboard wire harness
2 BLK (G401)
3 BLU/BLK (Trunk openindicator light control)
4 GRN/YEL (Hazard
warning switch input)
5 GRN/RED(Brake system indicatorlight control)
6 RED/BLU (Seat beltindicator light control)
7 '96-'97 model: BLU,ryEL(not used)
8 Except GX: GRN/YELGX: 8LU/GRN(Low fuel indicator lightcontrol)
9 D16Y7/D16Y8: YEL01685/016Y5:GRN/BLK(D4 or D indicatorcontrol)
10 GRN (03 or Sindicator control)
11 RED(N indicator control)
12 WHT(F indicator control)
13 BLI(BLU(P indicator control)
14 LT GBN(Park/neutral output)
10 Except GX: YEUBLKcX: ORN/BLU(Fuel gauge controlinput)
11 BLUAVHT(Vehicle speed sensor(VSS) input)
12 YEUGRN (Engine
coolant temperaturesending unit input)
14
15 BLI(IVHT(lgnition input)
16 WHT/BLU(Charging systemindicator light control)
202-30
Connector C
- Blue- On dashboard wire harness
1 *: YEL (lgnition input)
2 *: PNK (Washer lluidlevel input)
3 YEUBED(Low oil pressureindicator light control)
4 YEL (lgnition input)
5 GRN/ORN (Malfunctionindicator light control)
6 RED/GRN
{Lights on Hl input)
7 GBN/RED (Hazardwarning switch input)
*= '99-'00: All except CVT
Connector D
- Orange- On dashboard wire harness
BLU/RED (ABS
indicator light control)
8 BLU(Engine speed input)
10
12 FED(Dash light brightnesscontroller input)
13 RED/BLK (Headlightswitch ON input)
I
2
3
4
5
BLK (G401)
YEL (lgnition input)