1994 HONDA INTEGRA ecm connector

How to Read Flowcharts
A flowchrrt is dasigned to be us€d fiom start to final repair. lt's like a map showing you the shortest distanco. But be-
ware: if you go off tho "map" anywhere but a "stop" symbol, you can easily get lost
l6rffil Desclibas the conditions or situation to start a troubleshooting flowchart.(bold tyDo)
|TeTiONl Asks you to do something; pedorm a test, set up a condition etc'
<:6Eei6io-fr\> Asks you about the result of an action, then sends you in the appropriste troubleshooting direction.
I-SJTFI The snd of a series ot actions and decisions, describes I tinal repair action and aomotimea diracts
(bold typel you to 8n garlier part of the tlowchart to confirm your repair'
NOTE:
a Tha tarm ,,lntormittgnt Failure" is used in these chans. lt simply means a system may have had a failur6, but it chocks
out OK !t this time. lf th6 Msltunction Indicator Lamp (MlL) on ihe dash does not come on, check for poor connections
or loose wires at all connectors rolated to the cilcuit that you are troubleshooting (see illustration b6low).
a Most ot tho troublashooting flowchans have you reset the Engine Control Module (ECM) and try to duplicate the Disg-
nostic Troubls Cod6 (DTC). lf the problem is intermittent and you c8n't duplicat€ the cod6, do not continus through
the flowchart, To do so will only rosult in confusion and, possibly, a ne€dlessly replaced ECM
a ,,opon,'and ,,short,, are common electrical terms. An open is a break in a wir6 or at a conn€ction. A short is an
accidontal connaction ot a wir€ to ground or to another wire. In simple electronics, this usually means som€thing won't
work at all. In complex electronics (like ECM's), this can sometimes mean something wolks, but not the way it's sup-
poSad to,
a il th6 olectricsl readings are not as specified when using the test harness, check the test harness connoctions bsfore
procooding.
LOOSE
11-39

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
I| | o oooo oooooooo I oooo oooo I ooooool ooooooooooo I
G 10'l
11-42

Th. ll.lfunction Indicltor Lamp
lMlll at!y3 on o. cornaa on alt6ltwo aacond!.
Connect the SCS short connectorto th6 sorvice check connector(see page 11-34).
Turn the ignition switch ON.
Go to iolfdiagnostic Proceduros(se€ pago 11-34).Does the MIL indicate anv Oi-agnostic Trouble Code (DTC)?
Romove th€ SCS shon connectorlrom the service ch€ck connector.
Turn the ignition switch OFF.
Try to start the engine.
Connect the test harness betweenthe ECM and connectors (see
page 11-37).
Turn the ignition switch ON.
Measure voltage botween D4 (+ )terminal and D22 { - ) terminal.
connect the SCS shonconnector to servlcecheck connector.ls there approx. 5 V?
Ropair shon to body g.ound inBRN/WHT wire betwoon th6 ECMlD4) end sorvlco chock connocto?.Measure voltage be_tween D4 {+} terminaland body ground.
- R6pair open in BRN/WHT witobotwoon EcM lD4) and s6rv-ice chock connactor.- Repoir opon in BLK wiro bo-twoon 36rvi@ chock connectoaand G4Ol.
ls there approx. 5 V?
InsDoct ECU {ECM) 115 A) tuse inth6 undeFhood luse/relav box.
- Rsolaco ECU {ECM} (15 Allus€.- R6pair shon in YEL/WHT wilobotw6on ECU lEcMl 115 A)fuso and PGM-FI main rolay.
Remove the scs shortConnector from theservice check con-nector.
ls the luss OK?
NOTE:
a When there is no code stored, the MIL willstay on if the service check con-
nector is shorted.
a tf this svmotom is intermittent, check for:
- A loose ECM fuse (15A) in the under-hood tuse/relay box
- A loose No. 24 fuse (ACG) (ALT) ( 1 5A: B1 8B 1 engine, 2OA: B18C 1 en-
gine) in the under-dash fuse/relay box- An intermittent short in the BRN/WHT wire between the ECM (D4) and
the service check connector- An intermittent oDen in the BLK wire between the service check con-
nector and G4O1- An intermittent shon in the GRN/ORN wire between the ECM (A 13) and
the gauge assembly.- An intermittent short in the YELMHT wire between the ECM (D19) and
the MAP sensor- An intermittent short in the YEL/BLU wire between the ECM (D20) and
the TP sensor
o ooooo ooo ooo o loooooooo liii:$A$.Ps,l o oo ooo ooooo
o oooo ooo o o ooo I oooooooooooooooooo
D4 (+)
l"oo,o'.
D22 t-l
uu,l
'NOTE: After repair, disconnect the SCS ShortConnsctor, test drive the car, and recheckthe MIL
lor a code.
(cont'd)
(To page 1 'l -44)lTo page 1 1-44)
11-43

(From page 1 1-43)
Inspect the No. 24ACG {ALT) (lG)(15 A: 81881 engine, 2OA:818C1 enginel fuse in the under-dash fuse/relav box.
- R.pllr .hon in BLK|rEL wlr6batr.v€qr undariair luro/Fbybox lnd FGM-FI m.in .obv.- noebco lto. 24 ACG {lG) nLT)(15 A: 81881 ongin., 2OA:Bl8Cl onein.l tu!6.
ls the fuse OK?
Turn the ignition switch ON.
Disconnect the 3P connector oteach sensor one al a time:. MAP sensor. TP sensor
Rcplaoo thg lgnlor that caur6dth. llght to Oo out.Does the MIL remain ON?
Turn the ignition switch OFF.
connect the test harness.Disconnect the "D" connectorfrom th€ ECM only, not the mainwire harness (see page 11-37).
Check tor continuity betweenbody ground and D19, O2O ter-minals,
- Bapai? rhod ro body g.ound inYEL/WHT wi.e boiwoon ECM(Dl9) .nd MAP ..n3or.- R.p!k shon to body ground inYEL/BLU wire b.lwo6n ECM(O2Ol .nd TP 3on!or.
Reconnect all tho sensor con-necrors,Reconnect the "D" connector torhe ECM.
Turn the ignition switch ON.
{To page 11-45}
System
Control Module (ECMI (cont'dl
PGM-FI
Engine
Dt9I
I oooooooooo ooo I oooooooo I omoool o oooooooooo | |I ooooooooooooo I oooooooo 1o('oe(lo I ooooooooooo | |-lD2O I
\-.J
Continuity?
(From page 11-43)
Disconnect "A" con-nector from the ECM.
Subrtltute r knowngood ECM.nd rochock. ll lymptom/indics-tlon g@a rw!y, rephco tho origi-n.l ECM.
ls the MIL ON?
Ropair short to bodygiound in GRN/ORNwir6 botwoon tho ECMlA131 6nd MlL.
11-44

(From page 1l-44)
Measure voltage between 426
{- ) and the following: B'1 (+ } andA25 {+ t.
- Ropsir opon in YEL/BLK wirobotwoon ECM (425, 81l andPGM-FI m6in relay.- Chock PGM-FI main rclay andwiring connectors at PIGM-FImain.olay (soe psg6 11-1121.
ls there battery voltage?
Measure voltage between bodyground and the tollowing termi-nals individually: A23. A24, A26,42.
- noprir opon in BLK wit. b6-twson ECM 1A23, A24l andG'101 {locatod al th6.mostathousingl.Repair opon in BRN/BLK witebotweon ECM (A26, B2l andGl0r.
ls there less then 1.0 V?
Substitut6 r known{ood ECM
and r6chock. lf symptom/indica-tion goos away, roplaco tho origi-nal ECM.
BATTERYVOLTAGET
ooooooooooo
oooooooooooooooooooooo
ooooooooooo
oooooooo
ooooooo
L€ss than 1.0 V?
11-45

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

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}