1994 HONDA INTEGRA relay

lBl lcl
IT
tl
] I neonr-x
RED/WXT
c449 - C553F- GR[{/OR]{
To RADIATOR FAt{RELAY, COI{D€I{SERFAI{ RELAY
To A/C COTT|PfiESSORCLUTCH RELAY
To A/C SWITCH
(cont'd)
11-17
GAUGE ASSEMALY
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System Description
System Connectors IEngine Compartmentl
{818C1 onginol
ENGINEWIRE HARNESS
t3
c132
c131
UNDER,HOOOFUSE/RELAYaox
c102c222
ct 04c220
MAllrlWIREHARI{ESS
o
11-20

System Description
System Connectors [Dash and Floor]
PGM-FI MAINRELAY
C1I44 UNDEN-OASHFUSE/REALYBOX
ENGINECOMPARTMENTWIRE
DASHBOARO WIREHARNESS
MAINWIREHARI{ESS
REARWIREHARNESS
11-24

System Description
System Connectors [Dash and Floor] {cont'd}
UNDER-DASHFUSE/RELAYBOX
DASHBOARDHARNESS
MAINWIREHARNESS
11-26

Engine Control Modute {ECM) Reset procedure
1 . Turn the ignition switch otJ.
2' Remove th€ BACK UP (7.5 A) fuse trom the unde.-hood fuse/relay box for lo seconds to reset the EcM.
BACK UP I7.5 AI FUSE
UNDER-HOOOFUSE/RELAY BOX
Final Procedure lthis procedure must be done after any troubleshooting)
1. Remove the SCS Short Connector.
NOTE: lf the SCS short connector is connected and there are no DTCS sto.ed in the ECM, the MIL will stav on.
2. Do the ECM Reset Procedure.
11-35

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
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3. Fuel Cut-oft Control
a During deceleration with the throttle valve closed, current to the {uel injectors is cut otJ to improve fuel economy
at speeds over tollowing rpm:
. 8188l engine: 91O tpm (Canada model: 1,O50 rpm)
. 818C1 engine: 95O tpm (Canada model: l,O5O rpm)
a Fuel cut-olf action also takes place when engine speed exceeds, 7,O0O rpm {81 8B1 engine), 8,1O0 rpm (B 18Cl
engine), regardless oI the position of the throttle valve, to protect the engine from ovet-revving.
A/C Compressor Clutch Relay
When the ECM receives a domand for cooling trom the air conditioning system, it del8ys the compressor from being
enetgized, and enriches the mixture to assure smooth transition to the A/C mode.
Evaporative Emission (EVAP) Purge Control Solenoid Valve
When the engine coolant tempersture is below 163oF {73"C), the ECM supplies a ground to the EVAP pu.ge control
solenoid valve which cuts vacuum to the EVAP purge control diaphragm valve.
Intake Air Bypsss (lAB) Control Sol€noid Valve
When the engine rpm is below 5,750 rpm, the IAB control solenoid valve is activated by a signal from the ECM,
intske air flows through the long intake path, then high torque is delivered. At spaeds highe. than 5,750 rpm, the
solenoid valve is deactivated by the ECM, and intake air flows through the short intake path in order to reduce the
resistance in airflow.
ECM fail-safe/bEck-up Functions
1. Fail-sate Function
When an abnormality occurs in a signal from a sensor, the ECM ignores that signal and assumes a pre-progtammed
value tor that sensor that allows the engine to continue to run.
Back-uD Function
When an abnormalitv occurs in the ECM itself, the fuel iniectors are controlled by a back-up citcuit independent of
the system in order to permit minimal driving.
Self-diagnosis Function IMaltunction Indicator Lamp {MlL)1
Wh6n an abnormality occurs in a signal from a sensor, the ECM supplies ground for the MIL and stores the code
in erasable memory. When the ignition is initially turned on, the ECM supplies ground tor the MIL tor two seconds
to check the MIL bulb condition.
Two Trio Detection Method
To prevent tals€ indications, th€ Two Trip Dstection Method is used for the HO2S and fuel metering-related self-
diagnostic tunctions. When an abnormslity occurs, the ECM stores it in its memo.y. Wh€n the ssme sbnormality
recurs alter the ignition switch is turned OFF and ON ag8in, the ECM informs the driver by lighting the MlL.
However, to ease troubleshooting, this function is canc€ll€d when you short the service check connector. The MIL
will then blink immedistelv when an abnormality occurs.
4.
6.
2
4.
11-41

PGM-FI System
Engine Control Module (ECM)
lB18B1 ongino onlyl
The Malfunction Indicator Lamp(MlL) n6v6. com6s on lovon follwo socondal aftor ignition istumed on.
lurn the ignition switch ON.
Inspect No. 15 {BACK-UP LIGHT}l1O A) luse in the underdashtuse/relay box.ls the low oil pressure light on?
- R€placo No. 'l5
IBACK-UP LIGHT)llo Al fuso.- Ropair short inYEL wiro botwoonNo. 15 (BACK-UP
LIGHT) {10 A) fusoano gauge 6$om-blv.
Turn lhe ignition switch OFF.
ls the fuse OK?
Connecl the test harness betweenthe ECM and connectors (seepag€ 11-37).Repair opon in YEL wiio botw6onNo.'15 IBACK-UP LIGHTI 110 A)luso and gaug6 assombly.
Turn the ignition switch ON.
- RsDlaco tho MIL bulb.- Ropair opon in GRN/ORN wi.ebetwoen ECM {A13} andgaug€ a$6mbly.
ls the MIL on?
Measure voltage between body
Oround and the tollowing termi-nafs individuallv: 423, 424.
Ropah op6n in BLK wirolsl bo-tw6en ECM and GlOl llocatod atthormostat housing) that hadmoro than 1.0 V.
ls there less than 1.O V?
Substituto a known-good ECMand rochgck, lf symptom/indica-tion go€s away, roplaco tho origi-nal ECM.
NOTE: lf this svmptom is intermittent. check for a loose fuse No. 15 (BACK
UP LIGHT, 1OA) in the under-dash Juse/relay box, a poor connection at ECM
terminal A13, or an intermittent open in the GRN/ORN wire between the ECM(A13) and the gauge assembly.
I A13
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G 10'l
11-42