1998 HONDA CIVIC Scan tool

ldle Control System
ldle Air Control (lACl Vatve ('96 - 98 Dl6ys, Dl6yB engine with M/Tl
The scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt flAC) varvecircuit.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR ICl3A)
,flrcerh-:J iYEL/BLKI
!.__-,/ -lt(v)
-T-=
Wire side of female terminals
tAcv(BLK/
ELUI
ECM CONNECTOR A I32PI
Wire side oI lemal€ terminals
VALVE
6a10ll12t3r5t6l7t8t920232a
t*25&a2A3o
The MIL hss b€on repo.ted on.DTC P'l508 i. itorod.
Problem vorification:1. Do the ECM/PCM Reset Pro-cedure,Start the engine, and warm ituP to normal operating tem-perature.
Intormittont t!llur., sy.tcm b OKat thb tim6. Chsck fol poor con-ncctionr or loo3e wirot at C138(lAC valv.l.nd ECM.
ls DTC P1508 indicated?
Check for an opcn in the wiro(lGPl line):1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure vohage between bodyground and the IAC valve 2Pconnectorterminal No. 2.
R.prir opan in the wiro botwa.nIAC valv..nd PGM-FI main r.l.y.
Chock for an opon or sho in thewire (IACV linal:1. Turn the ignition switch OFFand reconnect the IAC valveconnector.2. Disconnect the ECM connectorA (32P).
3. Turn the ignit;on switch ON (ll).4. Measure voltage betweenbody ground and ECM con-nector terminal A12.
(To page 1l-195)
11-194

ldle Gontrol System
ldle Air Control (lAG) Valve ('99 - 00 Dl6Y8 engine with M/T, Bt6A2 enginel
[Fl50g l ]h" scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt AC) vatve- CtrCUtt.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR IC138'
la rcprI - {YEL/8LKI 2t--d,
Y-=
Wire side ot female terminals
Wire side of lemale terminals
VALVE
The MIL has boon r€oorted on.DTC P1508 is srored.
Probl6m verification:1. Do the ECM/PCM Reset Pro-cedure.2. Start the engine, and warm itup to normal operating lem-perature.
Intermittent tailure, system is OKat this timg. Check to. poor con-noctions or loose wires at C138{lAC valvel and ECM.
ls DTC P1508 indicated?
Ch6ck for an open in the wir€{lGPl lino}:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure voltage between bodyground and the IAC valve 2Pconneclor termina I No.2,
Repair opon in the wire bgtwoenIAC valve and PGM-Fl main relay.
Check tof an open or short in thewire {IACV line}l1. Turn the ignition switch OFFand reconnect the IAC valve
2. Disconnect the ECM connectorB {25P).3. Turn the ignition switch ON (ll).
4. Measure voltage betweenbody ground and ECM conn€ctor terminal 823.
(To page 11-197)
1 1-1 96

ldle Control System
ldle Air Control (lAC) Valve ('96 - 98 A/T and Dl6Y7 enginel
The (Rotary) IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from theECM/PCM in order to maintain the proper idle speed,
BIMETAL
VALVESTOPPER
1P1509 Thescantool indicates Diagnostic Trouble Code (DTC) P1509: A problem in the idle Air Control (tAC)valve circuit.
ECM/PCM CONNECTOR A I32PIPGl IBLKI
IAC VALVE 3P CONNECIOR
IACV NIACV P
IGP
Terminal side of maleterminals
*: IACV N line
1 1-198
The MIL has b€€n roported on.DTC P1509 is stored.
Problem verification:1. Do the ECM/PCM Reset Proce-oure.2. Turn the ignition switch ON (ll).
Intermittent failura, systom ia OKat this time. Check tor poo. con-noctions or loose wires at C109llAC valve) and ECM/PCM.
ls DTC P1509 indicated?
Check for an opon in the wirer{PG lines):Measure voltage between bodvground and ECM/PCII connectorterminals A10 and A23 individu
Repair op€n in the wires betwoenECM/PCM and G101 llocated attho thermostat housing).
ls there more than 1.0 V?
Chock th€ ECM/PCM inpui volt-agel1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P)from the ECM/PCM.3. Turn the ignition switch ON (ll).4. Measu re voltage betweenbody ground and ECM/PCMconnector terminals A14 andA13* individually.
Ch6ck th6 IAC valve:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 3Pconnector,3, Measure resistance betweenIAC valve 3P connector termi-nal No.2 and terminals No. 1and 3 individually.
ls there 16 - 28 g?
Substitute a known-good ECM/PCM and recheck. lf symptom/indication goos away, replaceth€ origin.l ECM/PCM.
SHAFT
rAcv N loRNl*
(To page 11-199)
Wire side of lemale terminals
123a56El011
121314r5161718t9202:22321
272AA30
IACV P {BLK/BLUI

ldle Gontrol System
The (Rotary) IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the
ECM/PCM in order to maintain the proper idle speed.BIMETALHOLDER
BIMETAL
SHAFTVALVESTOPPER
ECM/PCM CONNECTOR B {25P}
(To page 11-201)
IAC VALVE 3P CONNECTOR
IACV NIACV P
ldle Air Control {lACl Valve ('99 - 00 A/T and Dl6Y7 enginel
YES
1P1509 lThescantool indicates Diagnostic Trouble Code (DTC) P1509:A problem inthe idleAirControl (lAC)valve circuit.
IGP
Terminal side of maleterminals
Sub3titute e known-good ECM/PCM .nd recheck. lf 3vmptom/indicalion goos away, replac6thc original ECM/PCM.
*: IACV N line
11-200
Tho MIL has b€en reported on.OTC P1509 is sto.ed.
Problem verilicationr1. Do the ECM/PCM Reset Proce-dure.2. Turn the ignition switch ON (ll).
Intermittont tailure, sy3tem i3 OKat thb time. Check for poor con'noctions or loose wiros at C109(lAC velvel and ECM/PCM.
ls DTC P1509 indicated?
Check for an oDen in the wilosIPG linesl:Measure voltage between bodyground and ECM/PCM connectorterminals 82 and 810 individually.
Ropail open in the wires be'tw€enECM/PCM .nd G101 llocated .tthe the.mostat housingl.ls there more than 1.0 V?
Check tho ECM/PCM input volt-age:1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P)trom the ECM/PCM.3. Turn the ignition switch ON (ll).
4, Measure voltage betweenbody ground and ECM/PCMconnector terminals 86 and815* individually.
Chock the IAC v.lve:1. Turn the ignition sw;tch OFF.2. Disconnect the IAC valve 3Pconnoctor.3. Measure resistance betweenIAC valve 3P connector termi'nal No. 2 and terminals No. 1and 3 individually.
ls there 16 - 28 O?
Wire side of female terminals

4
The scan tool indicates Dlagnostic Trouble cod€ {DTc} Po4ol: lnsufficient flow in the Exhaust Gas Recirculation
(EGR) svstem.
Doscription
Deterioration (clogging, leakage, etc.) in the EGR line or EGR valve is detected by means of the changes in MAP before
and after the operation of the EGR valve.
lf deterioration has been detected during two cons€cutive driving cycles, the MIL will come on and DTC P0401 will be
stored.
Po$ible Causeg
. Clogging. leakage in the EGR line
. Faulty EGR valve
Troubleshooting Flowchart
\
- Tho MIL ht! bacn rgportod on.- DTC m40l is 3torod.
Problom vorification:
1. Do the ECM/PCM Reset Proce-
dure.2. Connect the SCS service con-
nector,3. Tost-drive under the following
conditions.- Without any electrical load- Decelerate lrom 55 mPh(88 km/h)lor at least 5 sec-
onos
lntormiftam f!ilu.a, ayltam ia OK
.t thb time,
- Clo.n tho inttkc mlnifold EGRport wittr carbursto. clotner.- Cl.an the pa$lgo insido tho
EGR valvo with crrburator
cloanol or aoglaca tha vllvo.

Emission Control System
Exhaust Gas Recirculation (EGR) System (D16Y5 engine with GWI (cont'dl
lTl49il T_he scan tool indicates Diagnostic Trouble Code (OTC) P1491: A malfunction in the Exhaust Gas Recirculation- lEgh) svstem.
CvT lM/T see page 1l-2611:
J
EGR VALVELIFT SENSOR#16 HOSE
PUMP/GAUGE,0- 30 in.HsA973X-041-XXXXX
EGRVALVE
The MIL has been reoorted on.DTC P1491 is stoled.
Problem verification:1. Do the ECM/PCM Reset Proce-du re.2. Connect the SCS service con'
3. Start the engine. Hold theengine at 3,000 rpm with noload {in Park or neutral) untilthe radiator fan comes on,4. Drive the vehicle on the roadfor approx. 10 minutes. Try tokeep the engine speed in the1,700 - 2,500 rpm range.
Intermittonl failure, system is OKat this time. Check for Door con-nections or loose wires at, C144{EGR velve} and ECM/PCM.
ls DTC P l49l indicated?
Check fo. vacuum to ihe EGR
1. Disconnect the No. 16 hose fromthe EGR valve.2. Connect a vacuum pump/gauge to the hose.3. Start the engine and let it idle.
ls there any vacuum?
Check tor a malfunction in theEGR control solenoid valve:'1. Disconnect the EGR controlsolenoid valve 2P connector,2. Becheck the No. 16 hose for
Check vacuum hose routing o,the entire EGR svstem. lf hoserouting is OK, replac€ the EGRcontrol solenoidvalv6.
ls there any vacuum?
Substitute a known-good ECM/PCM and recheck. It symptom/indicalion goes away, replacethe original ECM/PCM.
(To page 11 257)
11-256

J\
Exhaust Gas Recirculation System
The scan tool indicates Diagnostic Trouble
Recirculation (EGRlvalve lift sensor circuit.
(D16Y5 enginel
Code {DTC) P1498: A high voltage problem in the Exhaust Gas
EGR VALVE LlFf SENSOR 3P {M/T: 6Pl CONNECTOR (C1441
cvT:
vcc2{YEL/BLUI
SG2 IGRN/BLK)
IM/T:sG2{GRN/BLKI
Wir€ side ol lemale terminals
ECM CONNECTOR D (16P)
vcc2(YEL/BLUIsG2(GRN/BLK)
Wir€ side of female terminals
PCM CONNECTORS C 131P)'
Wire side oI female terminals
11-265
- The MIL has been reportod on.- DTC P1498 is storod.
Probl€m verification:1. Do the ECM/PCM Reset Proce
dure.2. Stan the engine.
Intermittent tailure, sy3lem is OK
at lhis time. Check tor poor con'
nections or loose wire3 at C144
|EGR valvel and ECM/PCM.
ls DTC P1498 indicated?
Check for an open in tho EGRvalv6 lift sen3or:1. Turn the ignition switch OFF.
2. Disconnect the EGR valve lift
sensor 3P (M/T: 6Pl connector.
3. Turn the ignition switch ON (ll).
4. Measure voltage between the
EGR valve litt sensor 3P lM/T:6P) connector terminals No. 3and No.2.
ls there approx.5 V?
Check lor op€n in th€ wire (SG2
line):Measure voltage between ECM/PCM connector terminals 010 andD1l (C18 and C28)*.
Repair open in tho wiro betwoen
ECM/PCM lDl1 (Cl8)r) and EGR
valvo lift sensor.ls there approx. 5 V?
Substitute . known-good ECM/PCM and recheck. ll symptom/indicrtion goes away, replacothe original ECM/rcM.
*:'99 - 00 D16Y5 engine with CVT

\J
\
,96 D16Y5 engine,,96 D16r,gngino,,96 Dt6Y8 engine {3edan)' 37 D16Y5 engino..97 D16r, engine {coupe: KA, Kc mod-
els. sedan: KA, KC, KL {DX} models. hatchback: all modols}''97 Dl6Y8 ongine (s€dan: KA' KC mod€lsl:
The scan tool indicates Diagnostic Trouble code (DTC) P0441: Evaporative Emission (EVAP) control system
insufficient purge flow.
Description
By monitoring the purge line vacuum with the MAP sensor, the ECM/PCM can detect insufficient EVAP control system
purge flow.
Possible Cau3e
. EVAP Purge Control Solenoid Valve
. EVAP Purge Control Solenoid Valve Circuit
. EVAP Control Canister
. Vacuum Lines
. ECM/PCM
Troubl93hooting Flowchart
Wire side of femaleterminals
EVAP PURGE CONTROI-sottNotD vALvE 2P
CoNNECTOR (Cl1al
r-+-r
I'l'l
lG-ro.*l'rr"r
O)
Y
(cont'd)
11-271
- The MIL has bsGn.eportad on.- DTC milal k rtored.
Pioblem vsrificJtion:1. Start the engine. Hold the
engine at 3,000 rPm with no
load {in Park or noutral) until
the radiator fan comes on.
2. Do the ECM/PCM Reset Proce'
dure,3. Connect the SCS service con-
nector.4. Test-drive under following con-
ditions on the road- Without any electrical load- A/T in E or E Position(M/T in 3rd-sth gear)- Engine sPeed betweon
1,200 - 2.400 rpm.- Decelerate {rom 50 mph (80
knl/h)to 15 mph (24 km/h)lntormittont lailuro, sFtorn b OK
at thi. timo. Ch€ck tor Poor con'
ncction3 or looac wir.3 at C144
{EVAP purgo control tolonoid
vrtv.l .nd ECir/FCttl.
ls DTC P0441 indicatod?
Ch.ck fo. !n op€n in the wiro l|(illinel:1. Turn the ignition switch OFF.
2. Disconnect the EVAP Purgecontrol solenoid valve 2P con_
neclor,3. Turn the ignition switch ON (ll)
4. Measur€ voltage between bodyground and the EVAP Purgecontrol solenoid valve 2P con-
nector terminal No 1.
Rop.ir opor in tho wir6 b€two€n
the EVAP purgo codtiol tolonoid
v.lvo rnd tho No 15 ALIERNA'
TOR SP SENSOR 17.5 A)lu.o.
{To page 11-272)