light HONDA INTEGRA 1994 4.G Owner's Manual

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

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

PGM-FI System
Electrical Load Detector (ELDI
tft;-]/ The Maltunction Indicaror Lamp (MlL) indicatss Diagnostic Trouble Code IDTC) 20: A probtem in-Li!- tne Electrical Load Detecror {ELD} circuit.
With lho SCS lhon connectolconnoctod {ree pago 11-34}, cod.20 is indicatod.
Do the ECM B6set Procedurs {seepage 1 'l-35).
Start engine and keep engin€speed at idle.Turn on headlights.
lntennlna tlllure, lyrtom lt Ol(!t irl. dm. (lgtt driv. mly [email protected] for Door connactlona oaloota wiro. rt C218 IELD, lndEctrt.
Ooes the MIL indicato code 20?
Romove the undgr-hood fusg/relay box and remove the tus6/relav box lowet cover.
Turn lhe ignition switch ON.
Measure voltage betw€on BLK/YEL (+l terminal and BLK (-)terminal.
Msasuro voltag€ b€tweon BLK/Y€L {+) terminal snd bodvground.ls there bartory voltagel
Rcpir oo.n in BLK wir.batwaan lha 3P connrc-tor lnd G2Ol {loc.t.dtroit ot angh|. comprn-m.r dghl .ld.l,
B.p.lr op.n in BLKrYEL wlrr b.-tw..n o.24ACG (ALn flcl115A: Bl88l .ngln!, 20 A:818C1cnginol fu!. In thr und.r{..htu.o/r.lly bor lnd tho 3P con-rcclo?.
View tromwire side
BLK (-)
(To page 11-7'l)
GRn/iED I - |
BLK/YEL I + I
11-70

PGM-FI System
11-72
While measuring voltage betweenDlO 1+) terminal and 426 l-)terminal, turn the headlighr switchto the second position (a) {low).
Does the voltage drop whenthe headlights are turned on?
Subrtitute . known-good ECMand rochock. lt 3ymptom/indic€-tion goos away, ioplaco th6 origi-nal ECM.
Electrical Load Detector (ELD) (cont'd)
425 t-t D10 l+), Doos Volrago Orop? ----------------J

ldle Control System
Alternator (ALTI FR Signal
This signals the ECM when the Alternator (ALT) as charging.
D9 l+)
Inspection ot ALT FR Sign.l.
Connect the tost harness betweenthe ECM and connectors. Discon-nect "D" connector from themain wire harnoss only, not theECM lsee page 11-37).
Turn the ignition switch ON.
Measure voltage between D9 (+ )terminal and A26 {-}terminal.
Sub{inno s known-good ECMand redrack. It pro.ctibod volt gola now availablg, ropllco tha orlg-inal ECM.
ls there approx. 5 V?
Turn the ignition switch OFF.
Reconnect "D" connector to themain wire harness,
Start tho engino. Hold the engine
!L3,099 rpm with no load (A/T in
LN] or El position, M/T in neutral)until the radiator tan comes on,rhen let it idle.
Measuro voltage between Dg (fl
terminal and 426 (- I terminal.
Does the voltage decreasewhen headlights and .eardelogger are turned on?Turn ths ignition switch OFF.
ALT FR rignal is OK.
o oo oo o ooooo
ooooooooooo
Voh.go?
ooooooooooo
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1 1-86
(To page 1 1-87)
=-

ldle ControlSystem
Brake SwitchSignal
This signals the ECM when the brake pedal is depressed.
11-90
Inlp.ction ot Brd(. Switcfi Siignal.
Are the brake lights on withoutdepressinO the brake pedal?ltuoacl ths braka .wilch {!.a !ac-don 191,
Inspect STOP, HORN (20 Allusein the undeFhood fuse/relav box.Oo the brake lights come on?
R.pl!c. STO P,HOR {2O A) tu...R.pdr dbrt In WtlT/GBI wlrr batu..nb?!ka .wltch a.rdsToP, HOR[{ (20 A}lura.
ls the luse OK.?
- Ropalr opon In WHT/GRN wirobatwoan b'lka lwltch andSTOP, HORTI {20 Al lu!o.- InlDect tho braka awitch la6a.6cdon 19).
Connect tho t€st harness to themain wire hamess only, not to theECM {see page 11-37).
(To page 'l1-91)

- ldle Speed Setting
Inspoction/Adiustment
NOTE:
a When the idle speed set, check the following items:
- The MIL has not been reported on.- lgnition timing- Spark plugs- Air cleaner- PCV svstem
a (Canada) Pullthe parking brake lever up. Stan the en-
gine, then check that the headlights are off.
1 Start the engine. Hold the engine at 3,000 rpm with
no load (A/T in S or @ position, M/T in neutral)
until the radiator tan comes on, then let it idle.
2. Connect a tachometer.
3. Disconnect the 2P connectot trom the ldle Air Con-
trol {lAC) valve.
Start the engine with the sccelerator pedal slightly
depressed. Stabilize the rpm at 1 ,OOO, then slowly
release the pedal until the engine idles.
Check idling in no-load conditions: headlights, blower
fan, rear defogger, radiator fan, and ai. conditioner
are not operatrng.
ldl€ spood should bo;
81881 ongino:
MlT48O ! 50 rym
An48O I 50 rpm
lin@or@oosition)
818C7 engine:48O ! 50 rym
Adjust the idle speed, if necessary, by turnmg the
idle adiusting screw.
NOTE: After adiust the idle speed in this step, check
the ignition timing (see section 231.
lf it is out ot spec. go back to step 4.
4.
e
Turn the ignition switch OFF.
Reconnect the 2P connector on the IAC valve, then
remove the BACK UP (7.5 A) fuse in the under-hood
tuse/relav box for 1O seconds to reset the ECM.
Restart 8nd idle the engine with no-load conditions
for one minute, then check the idle speed.
NOTE: (Canada) Pull the parking brake lever up.
Start the engine, then check that the headlights ate
off.
ldlo speed should be;
81881 ongino:
MTf75O ! 50 rpm
AIT75O t 50 rpm
(in[]or@positionl
818C1 engine: 750 1 50 rpm
(cont'd)
11-95

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

lntake Air System
Throttle Body
Description
The throttle body is ot the single-barrel side-draft 1ype.
The lower portion of the throttle valve is heated by en-gine coolant from the cylinder head. The idle adjusting
screw which increases/dec.eases bvDass air and the
Evaporative Emission (EVAP) Control Canister port are
located on the top of the throttle body.
IOLE AOJUSTING
THROTTLESTOP SCREW(Non-adiustsb16l
11-120
Insoection
CAUTION: Do not adiust the thlottle stop screw. lt ispreset at the lactory.
1. Start the engine. Hold the engine at 3,OOO rpm with
no load (A/T in S or E position, M/T in neutral) until
the radiator fan comes on, then let it idle.
2. Disconnect the vacuum hose (to the EVAP control
canister) from the top of the throttle body; connect
a vacuum, gauge to the throttle body.
VACUUM PUMPGAUGEA973X-O41-XXXXX
5.
3. Allow the engine to idle and check that the gauge
indicates no vacuum.
a li there is vacuum, check the throttle cable (see
page 1 1-'l 18, 119).
Check that vacuum is indicated on the gauge when
the throttle is opened slightly from idle.
a lf the gauge indicates no vacuum, check the throt-
tle body port. lf the throttle body port is clogged.
clean it with carburetor cleaner.
Stop the engine and check that the throttle cable
operates smoothly without binding or sticking.
a lf there are any abnormalities in the above steps,
check for:
- Excessive wear or Dlav in the throttle valve shaft.
Sticky or binding throttle lever at full close po-
srtron.
Clearance between throttle stop screw and throt-
tle lever at tull close Dosition.