1994 HONDA INTEGRA heater

@ ne-oving the radiator cap while the engine
is hot can cause the engine coolant to splay out, seri-
ously scalding you. Always let the engine and radiatol
cool down betore removing the radiator cap.
CAUTION: When poudng engine coolant, be sure to shut
the relay box lid and not to let coolant spill on the elec-
tlical pans or the paint. ll any coolant spills, rinse it otf
immediately.
1. Slide the heater temperature control lever to maxi-
mum heat.
Make sure the engine and radiator are cool to the
touch.
2. Remove the radiator cao.
3. Loosen the drain plug on the bottom of the radiator,
and remove the drain bolt from the enoine block. Let
the coolant drain out.
ENGINE DRAIN BOLT78 N.m {8,O kgt.m, 58 lbt.ftlApply liquid gasker tobolt thread when installing.WASHERReplace.
5.
Remove the reservoir from its holder by pulling it
straight up. Drain the coolant, then put the reservoir
back in its holder.
When the coolant stops draining, apply liquid gasket
to the drain bolt threads, then reinstallthe bolt with
a new washer. Tighten it securely
6. Tighten the radiator drain plug securely.
7. Mix the recommended antifreeze/coolant with an
equal amount of water in a clean container.
NOTE:
. Use only HONDA-RECOMMENOED antifreeze/
coolant.
a For best corrosion protection, the engine coolant
concentrations must be maintained year-round at
50% MINIMUM. Coolant concentrations less than
50% may not provide sufficient protection
against corrosion or freezing.
CAUTION:
a Do not mix ditterent blands ot anti-freeze/
coolants.
a Do not use additional rust inhibitois or anti-rust
products; they may not bs compatibl€ with the
recommgndsd engins coolant.
Engin€ Coolant Retill Capacity: including reservoir
{0.6 t (0.6 US qt, 0.5 lmp qt)).
81881 engine:
MlTt 4.4 | (4.6 US qt, 3.9 lmp qr)
Afft 4.7 [ (5.O US qt,4.1 lmp qt]
Bl8Cl engine:
Mnt 4.7 | (5.0 US qt.4.1 lmp qt)
8. Pour coolant into the radiator up to the base of the
filler neck.
9. Loosen the bleed bolt on top of the engine. Tighten
it again when coolant comes out in a steady stream
with no bubbles.
BLEED BOLT
1O. Refill the radiator to the base of the tiller neck. Put
the cap on the radiator. and tighten it only to the tirst
stop, Stan the engine and let it run until it warms
up (the radiator cooling fan comes on at leasttwice).
11. Turn oft the engine. Check the level in the radiator,
and add coolant it needed. Install the radiator caD,
and tighten it fully.
'1 2. Fill thereservoirto the MAX mark. lnstallthe reser-
voir cap.
9.8 N.m (1.O kgl.m, 7.2 lbf.ftl
Engine Coolant Refilling and Bleeding
10-5

System Description
Electrical Connections
PGM.FI MAII{ RELAY
- rc2l L
IllLii |
ril.i--r {a/Tl
To BAOIATOR FAt!RETAY, CONDENSERFAI{ RELAY
To A/C SWITCH
FUEL INJ€CTORS
@
DATALIIIKco t{EcToR
fUELPUMP
A/C CLUTCH RELAY
FUSES
O BATTERY I1OO AI*
@ oPTroN t50 alr
o rG {50 A).
@ sroP. HoBN {2O Al*
@ BACK UP (7.5 Al*
@ No. 3 INTERIOR LIGHT {7.5 A)
O Ecu (EcMt (1s A)'
@) No. 24 ACG (ALTI 0Gl{15 A: 81881 sngin6,2OA:818C1 6n9ine)
@ No. 15 BAcK-uP LlcHTs llo Al
@ No. 13 REAR DEFROSTER RELAYHEATER MOTOR RELAYCOOLING FAN MOTOR RELAY I7.5 A}
O No. l8 STARTER SIGNAL 17.5 A)
*: UNDER-HOOD FUSE/RELAY BOX
11-12
A/T GEAR

Troubleshooting
Self-diagnostic Procedures (cont'dl
':818C1 engine
a lf codes other than those listed above are indicated, verifv the code. lf the code indicated is not listed above, replace
rhe ECM.
a The MIL may come on, indicating a system problem when, in fact, there is a poor or intermittent electricalconnection.
First, check the electrical connections, clean or repair connections it necessary.
o The MIL and @ indicator light may light simultaneously when the Diagnostic Trouble Code (DTC) 6, 7 or 17. Check
the PGM-Fl system according to the PGM-Fl system troubleshooting, then recheck the l!! indicator light. ll it lights,
see page 14-5O, 51.
a The MIL does not come on when there is a malfunction in the A/T Fl signal or Electrical Load Detector (ELDI circuits.
However, it will indicate the codes when the Service Check Connector is shorted.
DIAGNOSTIC
TROUBLE
CODE (DTCISYSTEM INDICATEDPsge
oENGINE CONTROL MODULE IECM)11-42
,lHEATED OXYGEN SENSOR IHO25)1 1-46
aMANIFOLD ABSOLUTE PRESSURE {MAP SENSOR)11-52
4CRANKSHAFT POSITION (CKP SENSOR)1 1-56
oENGINE COOLANT TEMPERATURE (ECT SENSOR)11-58
THROTTLE POSITION (TP SENSOR}11-60
ITOP DEAD CENTER POSITION (TDC SENSORI1 1-56
9No. 1 CYLINDER POSITION (CYP SENSOR)1 1-56
10INTAKE AIR TEMPERATURE (IAT SENSOR)11-62
13BAROMETRIC PRESSURE (BARO SENSOR}1|-64
14IDLE AIR CONTROL (IAC VALVE}11-42
tcIGNITION OUTPUT SIGNAL11-66
toFUEL INJECTOR1't-102
17VEHICLE SPEED SENSOR {VSSI11-68
20ELECTRICAT LOAD DETECTOR (ELD)'t 1-70
21VARIABLE VALVE TIMING & VALVE LIFT ELECTRONIC CONTROL SOLENOID
VALVE {VTEC SOLENOID VALVE)'6-36
22VARIABLE VALVE TIMING & VALVE LIFT ELECTRONIC CONTROL PRESSURE
SWITCH (VTEC PRESSURE SWITCHI-6-38
23KNOCK SENSOR {KS}-11-7 4
30A/T FI SIGNAL A11-76
3'rA/T FI SIGNAL B1 1-76
4'lHEATED OXYGEN SENSOR (HO25} HEATER11-47
43FUEL SUPPLY SYSTEM1 1-50
11-36

PGM-FI System
System Description
ENGINE CONTROL MODULE (ECMIOUTPUTS
PGM-Fl System
The PGM-Fl system on this model is a sequential multipon fuel injection system,
Fuol Iniector Timing and Duration
The ECM contains memories tor the basic discharge durations at various engine speeds and manifold pressures. Thebasic discharge duration, after being read out from the memory, is turther modilied by signals sent from vanous sensofsto obtain the final discharge duration.
ldle Air Control
ldle Air Control Valve (lAC Vatve)
When the engine is cold, the A/C compressor is on, the transmission is in gear (A/T only) the brake pedal is depressed,the P/S load is high, or the alternalor is charging, the ECM controls current to the IAC Valve to maintain correct idle soeed.
lgnition Timing Controla The ECM contains mamories for basic ignition timing at various engine speeds and manifold pressures. lgnition timingis also adjusted for engine coolant temperature.a A Knock Control System is also used. when detonation is detected by the knock sensof. the ignition timing is retarded(B18Cl engine).
Other Control Functions
1. Starting Control
When the engine is started. the ECM provides a rich mixture by increasing fuel injector duration.2. Fuel Pump Control
a When the ignition switch is initially turned on, the ECM supplies ground to the PGM-Fl main relay that suppliescurrent to the fuel pump tor two seconds to pressurize the tuel system.a When the engine is running, the ECM supplies gfound to the PGM-Fl main relay that supplies current to the fuel pump.a When the engine is not running and the ignition is on, the ECM cuts ground to the PGM-FI main relav which cutscurrent to the fuel pump.
TDC/CKP/CYP Sensor
MAP Senso.
ECT Sensor
IAT Sensor
TP Sensor
HO2S
vss
BARO Sensor
ELD
Starter Signal
ALT FR Signal
Air Conditioning Signal
A/T Gear Position Signal
Battery Voltage {lcN. 1)
Brake Switch Signal
PSP Switch Signal
Knock Sensor'
VTEC Pressure Switchr
Fuel-lnjectors
PGM-FI Main Relay (Fuel Pump)
MIL
IAC Valve
A/C Compressor Clutch Relay
Radiator Fan Relav
Condenser Fan Relav
ALT
rcM
EVAP Purge Control Solenoid
HO2S Heater
VTEC Solenoid Valve'
IAB Control Solenoid Valve*
lFuet tnjector Timing and Duration]
I Electr..l"ldle Contr;il
Fit'e' contr; Funcrfit
l6tio; Ttntrlg c..trol
tEcM aack-,rp Functiorlsl
': 818C 1 €ngine
11-40

PGM-FI System
Heated Oxygen Sensor lHO2Sl
ztRcot{lAELEiIE'{T
HEATER
- --.'!- - -__-
lrPl _l !l-
-fi-l: The Malfunction Indicator Lamp (MlL) indicates Diagnostic Troubls Code (DTC) 1: A problsm in
/? the Heated Oxygen Sonsor (HO2S| circuit.
The Heated Oxygen Sensor IHO2S) det€cts th6 oxygon contont in th6 exhaust gas and signals th6 ECM. In operation,
the ECM receiv€s th6 signals trom the sensor and vari€s the duration during which tu6l is iniocted. To stabilize thd sen-aor's output, tho sensor has 8n intarnal heater and the sensor olemant is coatod with a catslyst. The HO2S is installod
in TWC housing (B18Cl engine) or exhaust pipe B (Bl8Bl €ngine).
sEl{SORTERMII{ALS
:tz-t6l-/ --.- \
VOLTAGE (V}sTotcHtoltETncAIR-FUEL BANO
HEATEBTEBMIT{ALSRICH - AN. - LEAI{FUELRATIO- Th! mll h.. bo.n raportad on.- Wlth thr SCS rhon coon cto.connoctad lr.. p!9. 1t-341,cod. t l. Indlcltrd.
Oo th€ ECM Res€t Procodure {soopag€ 11-35).
Stan the 6ngine. Hold th6 engine
A3,qgq rpm with no load {A/T in
Lryl or lll position, M/T in nourralluntil the radiator lan com6s on.then lot it idle lor ot least on6minutg beforo road t€6tin0.
Connoct ths SCS short connoctorto th6 sorvic€ check connectorlsoo p.g6 1 1-34).
Rood t€st witlthe automatictransmission in L?l position (M/T:4th gear).Stsrting st l,600 rpm, acc6lorateu6ing wide open throttlo for atlesgt 5 seconds. Thsn dgcol€rstefor at lorst 5 s€conds with th€throttlo completoly closed.
Intarmittd[ t llurc, lyri.m b Of!l thla tlmc. Ch.ck lor poor con-nacdona o? loota wlrat |l C223(loc.trd at right $ock towo.l,Cr 13 (HO2S| lnd ECM.
Ooes the MIL blink and doos itindic6t6 cod6 1?
Go to plga and partonn tad fotcod. 43 lr.a p.go l1-501.
1 1-46

mll )ffltl The Malfunction Indicator Lamp (MlL) indicates Diagnostic Trouble Code (DTCI 41: A problem in
Y- -:- the Heated Oxygen Sensor {HO2S) Heater circuit.
-.----r- \- l-l
tt(gt- -t tt I-r---7r
DIGITAL MULTIMETEBCommorcially availablo orKS-AHM-32-OO3
- Th6 MIL has boen roponod on.- With the SCS rhort connoc-to. connociod (aoe pago
11-341. codo 41 is indic.tod.
Do the ECM Reset Procedure {seepage 11-351.
Intoamittont tdl||.g, ryr-t m i3 OK at thi! timo(tost driv6 lnay bg ns-cearatYl.Chock tor poor conn6c-tions or looro wires atC223 llocatod at rightshod( row..l, C3O5 {lo-cated 6t loft ahock low-or), C424, C113(HO2S) and ECM.
ls the MIL on and does it indi-cste code 41?
Turn the ignition switch OFF.
Measurc tasistance betwgen ter-minals 3 snd 4 on the HO2S.
ls thero 1O-4O 0?
t€rminal side
(To page 1 1-481
(cont'd)

YES
PGM-FI
Heated
11-471
System
Oxygen Sensor Heater (cont'd)
YEL/BLK I+I ORI{/BLK (-I
wire side
HO2S44 N.m{4.5 kgt.m, 33 lbf.ft}
Check for continuity to bodyground on terminals 3 and 4of theHO2S.
Check for continuity between terminal4 and terminals 1 and 2 in-dividually.
Turn the ignition switch ON.
At the HO2S harness. measurevoltage between YEL/BLK 1f lteFminal and ORN/BLK l-) ter-mrnal.
Turn the ignition switch OFF.
Disconnect the "A" connectorfrom the ECM.Measure voltage between YEL/BLK l+) terminal and bodyground.
Turn the ignition switch ON.
At HO25 harness, measure vol-tage between YEL/8LK (+) termi-nal and ORN/BLK {-) terminal.
RoDair short in ORN/BLK wir6 b6tw6on ECM(A6l and HO2S.ls there baftery voltage?
Ropai. opon in YEL/BLKwire botwoan HO2S.nd PGM-FI main relav.
Turn the ignition switch OFF.Turn the ignition switch OFF.
11-48
{To page 11-49){To page 11-49}

ldle Control System
ldle Speed Setting (cont'd)
10.
9. ldle the engine for one minute with headlights {Low}
ON and check the idle sDeed.
ldla sp6od should bo;
81881 engine:
M/T750 i 50 rpm
An75O t 50 rpm
{in $ or p] positionl
818C1 engine: 75O 1 50 rpm
Turn the headlights off.
ldle the engine for one minute with heater tan switch
at Hl and air conditioner on, then check the idle
speeo.
ldls spood should bo;
81881 ongino:
M/T82O 1 50 rpm
AN840 1 50 rpm(in [N] or lll position)
818C1 engino: 85O t 50 nm
NOTE: lf the idle speed is not within specitication,
see System Troubleshooting Guide on page 1 1-78.
11-96