1998 HONDA INTEGRA coolant temperature

ldle Control System
Fast ldle Thermo Valve (A/T model onlylFast ldle I nermo valve (A/ | mooel
Description
To prevent erratic running when the engine is warming
up. it is necessary to raise the idle speed. The fast idle
thermo valve is controlled by a thermowax plunger.
When the engine is cold, the engine coolant surround-
ing the thermowax contracts the plunger, allowing addi
tional air to be bvoassed into the intake manifold so that
the engine idles taster. When the engine reaches operat-
ing temperature, the valve closes. reducing the amount
of air bypassing into the manifold.
FAST IDLE THERMO
VALVE
VALVE
wAx
Inspection
NOTE: The fast idle thermo valve is factory adiusted; it
should not be disassembled.
1. Remove the intake air duct from the throttle body.
2. Start the engine.
3. Put your finger over the lower port in throttle body
and make sure that there is air flow with the engine
cold {engine coolant temperature below 86'F, 30"c).
LOWERPORT
lf there is no air flow, replace the last idle thermo
valve and retest.
Start the engine. Hold the engine at 3,000 rpm with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
Check that valve is completely closed. lf not, air suc-
tion can be felt at the lower port in the throttle body.
l{ any suction is felt, the valve is leaking. Check
engine coolant level and for air in the engine
coolant system (see section 10). It OK, replace the
fast idle thermo valve and recheck.
5.
{1.0 kg.m,7.2lbftl
l
11-110
lL.

Description
Elestronic Control System (cont'd)
. GRADE LOGIC CONTROL SYSTEM
How it works:
The TCM compares actual driving conditions with driving conditions memorized in the TCM. based on th€ input from the
vehicle speed sensor, throttle position sensor, engine coolant temperature sensor, barometric pressure sensor, bral(e
switch signal and shift lever position signal, to control shifting while a vehicle is ascending or descending a slope, or
reducing speed.
SIGNALS DETECTED
{l
{
Driving ResistanceJudgement of Controlling Aroa
. Ascending mode(Fuzzy logicl. Gl.dual Ascending mode' Steop Asconding mode' oesconding mode. Gradu.l D$conding modo. Slecp D$conding modo
\-t {t

'.J
THROTTLErcsm0NSENSOR
ENGINECOOLANTTEMPERATURESENSOR
WHT/BLKBLK/RED
820424
OBNREO/BLK
84
J
MAINSHAFI COUNTERSHAFISPEED SENSOR SPfED SENSOR
I SHIFT CONTROL I LOCK -UP CONTBOL
+135Eil,?1o'uo'u' 4i85El,o''P'uo'u'
TCM T6nninal locations
TCM -B l22P)Conn€ctor
VREF IATCHK IBASOSS IAFSA IAFSB IFAS ISCS
----T;- t-T-*
+.. | +.., I + ,+
l+ | J l/vt-l .i{-'1M-l L-{-lr^/t-lt't'/!-?
*\::
r--rr!\.1 -r!\./ rartsurssrot coNTFoL M'DULE tTcMr
ltEltn r' -rrt= t= t? t=
NMSG INC INCSG ISH A ISH B ILC A ILC B
576I101112578I10
151617,/1,/20251214,/1,/171920,/1,/J
TCM -A (26P1 Connector
14-47

Terminal NumberSignalDescriptionMaasuring Conditlons/Tarminal Voliage
424ACCLAir conditioning (Ay'C) clutch relay
control
With A,/C comDressor ON: 0 V
With Ay'C compressor OFF: Battery voltage
A25tG1Power supply systemWith ignition switch ON (ll)r 12 V
426LG1Ground
B1Not used
82BAROS SBarometric pressure sensor signal
input
With ignition switch ON (ll) and depending on
barometric pressure: Approx. 3 V
B3ECTEngine coolant temperature sen-
sor signal input
With ignition switch ON (ll) and depending on
engine coolant tem perature: Approx. 0.1 - 4.8 V
B4TPSThrottle position sensor signal
input
With ignition switch ON (ll) 8nd throttle fully
open: 4.14 - 4.82 V
With ignition switch ON (ll) and throttle fully
closed: 0.44 - 0.56 V
B5VSSVehicle speed sensor signal inputWith ignition switch ON (ll) and front wheels
rotating; Pulsing signal
B6AFSBUpshifvdownshift comparative
signal output
With engine idling: 0 V
At uDshift or downshift: 5 V for an instant
B7AFSAUpshifvdownshift com parative
srgnal output
With engine idling: 0 V
At upshift or downshift: 5 V for an instant
B8NCSGCountershaft speed sensor signal
ground
Always: 0 V
B9NCCountershaft speed sensor signal
Input
Depending on vehicle speed: Pulsing signal
When vehicle is stopped:0 V
B10NMMainshaft speed sensor signal
input
Depending on vehicle speed: Pulsing signal
When vehicle is stoDoed: 0 V
811Not used
812STOP SWBrake switch signal inputWith ignition switch ON {ll) and b.ake pedal
depressed: Battery voltage
With ignition switch ON (lll and brake pedal
released:0 V
813Not used
814scsTiming adjustment
service check signal
With ignition switch ON (ll) and service check
connector oDen:5 V
With ignition switch ON (ll) and service check
connector connected with special tool: 0 V
815Not used
816Not used
817NMSGMainshaft speed sensor signalgroundAlways: 0 V
818Not used
819FASShift acknowledge inputWith engine idling: 5 V
At upshift or downshift: 0 V for an instant
820VBEF+5 V referenceWith ignition switch ON {lll: Approx. 5 V
82'lNot used
Not used
14-49

Electrical Troubleshooting
Troubleshooting Flowchart - Engine Coolant Temperature
(EGTISensor
Polribl. Cluta
. Dirconnoct.d Engin. CoollntTampaolur€ IECTI aanaor con.noctot. Short or opcn In ECT..n.or
. F.ulty ECT r.n.or
Tctrrt oot{NEcToRs
WIRE SIDE OF FEMAII TERi'IINAIS
U
{
M6esur. ECT Voh.ge:1. Turn the ignition switch OFF.2. Connect the A (26P) andB (22P) connectors to the TCM.3. Start the engine and w6rm ituP to normal operating tem-pe ratu re (the radiator fancomes on),4, Measure the voltage betweenthe 83 and A13 or A26 termi-nats.
Ii
:
rt.fls there less than 1 V?
Ch.cl fo. looso TCM connac{or3,t nacaasary, substituto a known"good TCM rnd r.chock.
' OBD ll Scsn Tool Indicat6 CodeP1792.. Sett'diagno3i3 E indicatollight indicates Code 10.
Chock tor Anothor Codo or MILBlinking:1. Turn the ignition switch ON (ll).
2. Check wh€ther rhe OBD llscan tool indicates anothercode or the Malfunction Indi-cator Lamp (MlL) blinks (see
section 11).
Does the OBD ll scan tool indi-cate another code or is theMIL blinking?
Moasure VREF Voh.go:1. Turn the ignition switch OFF.2. Disconnect the A {26P) andB (22P) conneotors from theTCM.3. Turn the ignition switch ON (ll).
4. Measu.e the voltage betweenthe 820 and A13 or A26 tormi-nals.
Bap|ir open or thort in tha wircb.two.r th. B:m t.rminll .nd thoECM.
ls there approx. 5 V?
napalr opln in iha wlra brtwaanthe lB t.rminrl lnd th. ECT r.n-ao1.

Electrical Troubleshootin g
Troubleshooting Flowchart - LC Control System
\.r.Poeribl. C.ua.
control
NOTE: Do not continue with this troubleshootingot any other DTCS have beeo corrected.until thg caus€s
v
t,
I
'I
14-80
Chock lor Anothor Cod6:Check whether the OBD lltool indicates another codo.
P6rform tha TroublorhootingFlowcha for tho indicrladCodolsl.R.ch.ck fof codo P0740 !ft.tt.oublo3hooting.
Does the OBD ll scan tool indi-cate another code?
Tost Line Proisurg:Measure the line pressure (see
pag6 14-98).
R.prir tho hydraulic syltcm !!n.cGsary (soc pago 1+98).ls the line prsssure within theservic€ limit?
Repl!c6 th6 Lock-up ControlSolenoid Velva As3ambly .ndRschock:1. Replace the lock-up controlsolenoid valve y'y'B assembly(see page '!4-87).
2. Turn the ignition switch OFFand reset the TCM memoryby removing the BACK UPfuse in the und€r-hood fuse/rolay box tor more than 10seconos.3. Using the OBD ll scan tool,check that the engine coolanttemperatures is 176'F (80'C)
4. Drive the vehicle at 55 mph(88 km/h) constantly lor rnorethan one mrnute,5. Recheck for code P0740.
Does the OBD ll scan tool indi-cate codo P0740?Tha iy3t6m ir OK .t thi! timc.
V
I
J

Troubleshooting
Engine Coolant Temperature(ECT}Switch
Both fans (radiator and con-denserl do not run for enginecooling, but they both run withthe A,/c on.
Disconnect the engine coolanttemperature lECT) switch 2P con
Turn the ignirion switch ON ( ll).
Measure the voltage between theGRN wire terminal (+) and bodyground (-)-
Repair open in the GRN wire b€-tween the ECT switch and theunder-hood luse/rel6v box,ls there battery voltageT
Turn the ignition switch OFF andcheck for continuity in the BLKwire between the ECT switch andbody ground.
Check for en ooen in the BLKwire between the ECT switchand body ground. ll th. wire isOK, check lor poor ground atG101.
ls there continuity?
Check the temperature gauge.
Does it read above normal?
View from wire side
GRN (+)

Connector ldentification and Wire Harness Routing
Connectot or
Terminal
Numbel of
CavitiesLocationConnects toNotes
c'to 1
c102
c103
c'1 04
c105
c106
c 107
c108
c108
c109
c110
c112
c113
c'r 14
c115
c116
c117
c118
ct'l9
c119
c120
c121
c122
c124
c't 26
c127
c128
c129
c130
c111
4
10
14
6
I
1
2
2
10
2
3
2
J
4
3
3
2
2
I
3
2
2
2
2
2
I
2
14
Right side of engine compartment
Right side of engine compartment
Right side ot engine compartment
Right side of engine compartment
Right side oI engine compartment
Right side of engine
Right side of engine
Transmission
Transmission
Middle ot engine
Middle ot engine
Right side of engine
Right side of engine compartment
Middle rear of engine compartment
N4iddle of engine
N4iddle ol engine
Middle oI engine
Nliddle ot engine
Middle of engine
Lelt side of engine
Left side of engine
Middle of engine
Middle oI engine
Middle of engine
Middle of engine
Middle ot engine
Left side of engine compartment
Lelt side ot engine compartment
Left side of engine compartment
Transmission
Transmission
Transmission
Main wire harness (C221)
Main wire harness (C222)
Main wire harness 1C223)
lvlain wire harness (C220)
Starter solenoid
Engine coolant temperature (ECT)
sensor
Engine coolant temperature (ECT)
gauge sending unit
Back-up light switch
Lock-up control solenoid valve A and B
Distributor
Crankshatt speed fluctuation (CKF)
sensor
Engine coolant temperature (ECT)
switch
Vehicle speed sensor (VSS)
Primary HO2S
MAP sensor
Throttle position (TP) sensor
ldle air control (lAC) valve
EVAP purge control solenoid valve
Engine oil pressure switch
Alternator
Alternator
lntake air temperature (lAT) sensor
No. 1 fuel injector
No. 2 fuel injector
No. 3 fuel injector
No. 4 fu€l injector
Junction connector
Engine compartment wire harness
(c304)
Engine compartment wire harness
(c30s)
Shift control solenoid valve A and B
Countershaft speed sensor
lvlainshaft speed sensor
M/T
NT
USA
Canada
Afi
Afi
T101
T102
Left side oI engine
Right side of engine compartment
Alternator
Under hood fuse/relay box
G'1 01Right side oI engineEngine ground. via engine wire
harness
Engine Wire Harness (B188l enginel
23-16