engine coolant HONDA CIVIC 1999 6.G Repair Manual

Troubleshooting -'96 - 98 Models
Symptom Chart
NOTE;
. Check the engine coolant level. and allow the engine to warm up before troubleshooting.
. Any abnormality must be corrected before continuing the test.
. Because of the precise measurements needed. use a multimeter when testing.
o Before performing any troubleshooting procedures check:- Fuses No. 41 11.5 Al, No. 55 (40 A) in the under-hood fuse/relay box. and No. 17 (7.5 A) in the under-dash fuse/relay
box- Grounds No. G401, G402- Cleanliness and tightness of all connectors
SymptomRomedy
Hot air flow is low.Blower motor runs. but one or more
speeds are inoperative.
Perform the procedures in the flowchart (see page 21-8).
Blower runs properly.Check for the following:. Clogged heater duct. Clogged heater outlet. Incorrect door position
No hot air flow.Blower motor does not run at all,Perform the procedures in the flowchart (see page 21-10).
Blower motor runs.Check for the following:. Clogged heater duct. Clogged blower outlet. Clogged heater valve. Faultv air mix door. Heater valve cable adjustment (see page 21-44). Air mix control cable adiustment (see page 2'l-441. Faulty cooling system thermostat (see section 10). Clogged evaporator (with air conditioning). Frozen evaporator {with air conditioning)
Mode control motor does not run, or one or more modes
are inooerative.
Perform the procedures in the flowchart (see page 21-13).
Recirculation control door does not chanqe between
FRESH and RECIRCULATE.
Perform the procedu.es in the flowchan (see page 21-16).
Both heater and A,/C do not work.Perform the procedures in the flowchart (see page 21-18),
21-6

Troubleshooting -'99 - 00 Models
Symptom
Mode control motor does not run, or one or more modes are inoperat've'
Recirculation control door does not change between Fresh and Recirculate'
Blower motor only runs on high speed position; it does not run in any other speed positions
Blower motor does not run at all.
Both heater and Ay'C do not work
See pags
a1_tq
21-21
21-29
21-31
21 35
Symptom Chart
For electrical malfunctions which are indicated by the self-diagnostic system, refer to self-diagnosis function (see next
page).
Note these items before troubleshooting a symptom'
. Check the engine coolant level, and allow the engine to warm up before troubleshooting'
. Any abnormality must be corrected before continuing the test
.Becauseoftheprec|semeasurementsneeded,UseadigitaImu|timeterwithanoutputoflmAor|essatthe20ko
range when testing
. Before performing any troubleshooting procedures check:
- Fuses No. 41 115 Al, No 55 (40 A)]n the under-hood fuse/relay box' and No 17 (7 5 A) in the under-dash fuse/relav
box- Grounds No. G401, G402
- Cleanliness and tightness of all connectors
21-19

Heater Unit
Replacement
SRS components are located in this area. Review the
SRS component locations, precautions, and procedures
in the SRS section {24} before performing repairs or ser-
L Disconnect the negative cable from the battery.
2. Frcm under the hood, open the clamp, then discon-
nect the heater valve cable from the heater valve
arm. Turn the heater valve arm to the fully opened
position as shown.
When the engine is cool. drain the engine coolant
from the radiator (see section 10).
!@ Do not remove the radiator cap when
the engine is hot; the ongine coolant is under pres'
surg and could severely scald you.
CLAMP
HEATER VALVC CABLE
4. Disconnect the heater hoses from the heater unit.
CAUTION: Engine coolant will damage p8int.
Ouickly rinse any spilled engins coolant from painted
su aces,
NOTE: Engine coolant will run out when the hoses
are disconnected; drain it into a clean drip pan.
5. Remove the mounting nut from the heater unit.
NOTE: When removing the mounting nut, take care
not to damage or bend the fuel lines, the brake
lines, etc.
I x 1 .25 mm22 N.m {2.2 kgl.m, 16lblftl
21-39

Heater Unit
Replacement (cont'dl
6.
7.
8.
9.
Remove the dashboard (see section 20).
Remove the heater duct (see page 21-37) or evapo-
rator (see page 22-28).
Disconnect the connectors from the mode control
motor and air mix control motor ('99 - 00 models),
then remove the wire harness clips and wire har-
ness from the heater unit. Remove the clip from the
heater duct, then remove the two mounting nuts
and the heater unit.
6x1.0mm9.8 N.m 11.0 kgl.m,7.2 lbf.ftl
HEATER UNIT
lnstall in the reverse order of removal. Make note of
the following items.
Apply sealant to the grommets.
Do not interchange the inlet and outlet heater
hoses. Make sure that the clamps are secure.
Refill the cooling system with engine coolant
(see section 10).
Connect all cables, and make sure they are prop-
erly adjusted (see page 21-44 (96 - 98 models)
or page 21-45 ('99 - 00 models)).
Make sure that there is no air leakage.
21-40

Connector ldentification and Wire Harness Routing
Engine Wire Harness lD16Y5, D16Y8 enginss): '96 - 98 models
Connector or
Torminal
Numbsr of
CavitissLocationConnects toNot€s
c 101c102c103c104c104c105c106c107c108c 109c110c111c112c113c114c115c116cl17c118c119c120cl21
c122c123cl23c124
c125
c127c12Ac129c130c131c132c 133c134c135
c136
c138c139c140c 141c142c 143c144cl44c145c'146cl47
10
1
22
14l4322l0I
2
2
2
2120
3l
14
14
1222
2
2
22
Left side of engine compartmentMiddle of engineMiddle of engineLeft side of engine companmentLeft side of engine compartmentMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of enginefvliddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineLeft side of engine compartmentMiddle of engineMiddle of engineMiddle of engineMiddle of engine
Middle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineRight side of engine companmentBehind right kick panelUnder right side of dashUnder riOht side of dashUnder right side of dashUnder right side of dashUnder right side of dashUnder right side of dash
Under right side of dash
Under right side of dash
Middle of engineMiddle ot enginel iddle of engineMiddle of engineMiddle of ongineMiddle of engineLeft side of engine compartmentMiddle of engineMiddle of engineRight side of engine compartmentRight side of engine compartmentRight side of engine compartment
USACanada
Afi
USA
-' (A/r)
Main wire harness (C303)Crankshaft speed fluctuation (CKF) sensorEngine oil pressure switchAlternatorAlternatorNo. 'l fuel injectorNo. 2 fuel injectorNo.3 fuel injectorNo. 4 fuel injectorIAC valveThrottle position (TP) sensorl\4anifold absolute pressure (MAP) sensorIntake air temperature (lAT) sensorPower steering pressure {PSPI switchEVAP purge control solenoid valveJunction connectorJunction conn€ctorVehicle speed sensor {VSS}Countershaft speed sensorEngine coolant temp€rature (ECT) switch ADistributorEngine coolant temperature (ECT) sendingunrtEngine coolant temperature (ECT) sensorPrimary HO2S (sensor'l)Primary HO2S (sensor 1)Back-up light switchLock-up control solenoid valveSecondary HO2S (sensor 2)Mainshaft speed sensorLinear solgnoid valveShift control solsnoid valveStarter solenoidJunction connectorMain wire harnesE (C446)ECM/PCMPCMECMiPCMECM/PCMMain wire harness (C305)
Main wire harness (C305)
Main wire harness (C305)
Knock sensor (KS)IAC valveVTEC solenoid valveVTEC pressure switchEVAP control canister vent shut valveEGR control solenoid valveSecondary gear shaft speed sensorEGR valveEGR valveDrive pulley speed sensorSolenoid connector {CVT)Driven pulley speed sensor
*, (M/T)M/T*" INT\
*, tAtf)
NT:'96 model*,(A,/T):'97 - 98mooets
moqets
M/T
-1 (l,/T)*, (A,/T)-,(4,/T)*1 {M/T)*, (A,/T)*1 (CW)*, (A,T)
T101r102Left side of engine companmentRight side of engine companmentAlternatorUnder-hood fuse/relay boxG 101Middle of engineEngine ground, via engine wire harness
2
*1: Dl6Y5 engine*2: D16Y8 engine*3: D16Y5 (Ay'T), D16Y8 engines
3-16

Gonnector ldentification and Wire Harness Routing
Engine Wire Harness (D16Y5, Dl6Yg engines): ,99 - 00 models
Connectot or
Terminal
Number ot
CavitiesLocationConn€cts toNotes
c'101cl02c103c104c 104c10s
c107c 108c'r09c110c111cl12c113cl14c l15c116cl17c118c119c120cl20c121
c122c123c123cl23cl24c124c125
c127c12Ac129c 130c131cl32c133c 134c135c137c138c 139c 140c142c143c144cl44c145c146c147
103,]
322223332221414322'10
8,l
2484224222120
32
2212223
282
No. 1 luel injector INo.2 fuel injectorNo.3 fuel injector ]No. 4 fuel injector iIAC valve I anThrottle position lTP) sensorManifold absolute pressure {MAP) sensor IIntake air temperature (lAT) sensor IPower steering pressure (PSP)switch USAEVAP purge control solenoid valve ]
Main wire harness 1C303)Crankshaft speed fluctuation (CKF) sensorEngine oil pressure switchAlternatorAlternator
Left side ot engine compartmentlvliddle of engineMiddle of engineLeft side ot engine compartmentLeft side of engine compartmentMiddle of engineMiddle ot engineMiddle of engineMiddle of engineMiddle oI engineMiddle of engineMiddle of engineMiddle of engineMiddle of engineNliddle of engineMiddle of engineMiddle of engineMiddle of engineRight side of engine compartmentMiddle of engineMiddle of engineN4iddle of engineMiddle of engine
Middle of engineMiddle ot engineMiddle ot engineMiddlo of engineMiddle of engineMiddle ot enginelrliddle of engineMiddle of engineMiddle oI engineMiddle ot engineRight side of engine compartmenlBehind right kick panelUnder right side of dashBehind right kick panelBehind right kick panelBehind righr kick panelBehind right kick panelMiddle ot engine[,liddle of engineN4iddle of engineMiddle of engineMiddle oI engineLeft side of engine compartmentMiddle of engineMiddle of engineRight side ol engine compartmentRight side of engine companmentRight side of engine compartment
USACanada
Junction connectorJUnct|On COnnectorVehicle speed sensor lVSS)Countershaft speed sensorEngine coolant temperature {ECT} switch ADistributorDistributorEngine coolant temperature (ECT) sendingunitEngine coolant temperature (ECT) sensorPrimary H02S (sensor 1)Primary HO2S (sensor 1)Primary HO2S lsensor 1)Back-up light switchLock'!p control solenoid valveSecondary HO2S (sensor 2)Mainshaft speed sensorLinear solenoid valveShift control solenoid valveStarter solenoidJunction connectorMain wire harness (C446)ECM/PCMECM/PCMECM/PCMPCtvtKnock sensor (KS)IAC valveVTEC solenoid valveVTEC pressure switchEGR control solenoid valveSecondary gear shaft speed sensorEGR valveEGR valveDrive pulley speed sensorSolenoid connector (CVT)Driven pulley speed sensor
*' (A/TI
*1 (CVT)*, (M/T)
Mfia (A/Tl
" (A,/T)., (4,/r)-' {AlrJ
*1 (M/T)
tvliT
*1 (CVT)*, (cvT)*' (cw)*1 (MiT)*1 {CVT)*1 {CVT)*, (cvr)
T101T102Left side of engine companmentRight side ot engine companmentAlternatorUnder'hood fuse/relay boxG 101Middle of englne IEngine ground, via engine wire harness*1: 016Y5*2: D16Y8*3: Dl6Y5
engineengine(CW), D16Y8 engines
23-14

Gonnector ldentification and Wire Harness Routing
Engine Wire Harness {D16Y7 engine}: '96 model
Conneclor or
Terminal
Number ot
CavhiesLocationConnects toNotes
c101
c102
c 103
c104
c104
c105
c'r06
c107
c 108
c 109
c110
c111
c112
c l13
c't14
LttS
cl16
cl17
c118
cl19
c120
c121
c123
c124
c124
c125
c126
c't27
c12a
c129
c130
c131
c132
c133
c134
c135
10
1
4
5
'14
14
10
1
,,
2
2
1
22
31
16
No. 1 fuel injector INo. 2 fuel injector
No. 3 fuel injector INo,4 fuel injector
IAC valve l
Throttle position (TP)sensor IManifold absolute pressure (MAP) sensorIntake ai. temperature (lAT) sensor ]Power steering pressure (PSP) switch I USAEVAP purge control solenoid valve IJunction connector
Junction connector IVehicle speed sensor (VSS) |Countershaft speed sensor AlTEngine coolant temperature (ECT) I
Main wire harness (C303)
Crankshaft speed fluctuation (CKF)
sensor
Engine oil pressure switch
Alternator
Alternator
switch A
Distributor
Engine coolant temperature (ECT)
sending unit
Engine coolant temperature lECT) sensor
Primary H02S (sensor 1)
Back-up light switch
Lock-up control solenoid valve
Secondary HO2S (sensor 2)
Mainshaft speed sensor
Linear solenoid valve
Shift control solenoid valve
Staner solenoid
Junction Connector
Main wire harness {C446)ECM/PCM
PCM
ECM/PCM
ECM/PCM
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
USA
Canada
M/T
AtJ
Afi
T101
T102
Left side of engine compartment
Right side of engine compartment
Alternator
Under-hood fuse/relay box
G101Middle of engineEngine ground, via engine wire harness
23-20

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