1998 HONDA CIVIC D16Y8

Engine Control Module/Powertrain Control Module (ECM/PCM)
('95 - 00 Models except Dl6Y5 engine with M/T)
NOTE:. When there is no Diagnostic Trouble Code lDTC) stored, the MIL will staY on if the SCS
seruice connector is connected and the ignition switch is on.. lf this symptom is intermittent, check for:- A loose No. 25 (METER) {7.5 A) fuse in the underdash fuse/relay box- A loose Fl E/M (15 Alluse in the undeFhood fuse/relay box- A loose No. 13 FUEL PUMPfuse (15 A) in the under-dash fuse/relay box- An intermittent shon in the wire between the ECM/PCM (A18) and the gauge assem'
- an intermittent short in the wire between the ECM/PCM (C19) and the MAP sensor- An intermittent short in the wire between the ECM/PCM {C28), the TP sensor, the
EGR valve lift sensor (D16Y5 engine) and/or the Fuel tank pressure sensor ('96 D16Y8
engine (coupe),'97 D16Y7 engine lcoupe: KL model, sodan: KL (LX) model)"g7
Dt6Y8 engine (coupe: all mod;ls, sedanl KL model),'98-all models,'99-al' models''00-all models.- PGM'FI main relay. See the oBD ll scan tool or Honda PGM Tester user's manuals for specific operating
instructrons,
ECM,/PCM CONNECTOR A I32PI
Wire side of {emale terminals
The Mrlfunction Indicator LamP{MlL) never comes on {even tor
two seconds) after ignition is
turned ON lll).
Turn the ignition switch ON lll).
- Repair shott or open in thowire bstwoon No. 25 IMETER)l?.5 A)tuse and gauga tsom_blv.- Reolace No. 25 (METERI (7.5
Alluse.
ls the low oil pressure light on?
Try to start the engine.
Check for an opon in the wire orbulb (MlL line):1. Turn the ignition switch OFF.2. Connect the ECM/PCM con'
nector terminal A18 to bodyground with a iumper wire.
3. Turn the ignition switch ON (ll)
Does the engine start?
- Repair open in tho wire3
betwoon ECM/PCM (A18) andgaugo .*tembly.- Rool.ce the MIL bulb.
Substitute a known-good ECM/
PCM and rochoc&. lf sYmptom/indication goes sw6y, repl.ce
tho original ECM/PCM.Turn the ignition switch OFF.Inspect Fl E/M (15 A)fuse in theunderhood Iuse/relay box.
Rop.ir short in the wirc
betwo€n Fl E/M (15 A) luso
and PGM-Fl mrin rGl.y.Reol.ce Fl E/M (15 A)tusa.
lnspect No. 13 FUEL PUMP {15 A}
luse in the under-dash fuse/relay
- Reoair short in the wiro
between No. 13 FUEL PUMP
115 Al luse sod PGM-FI mainrelay.- Reolace No. 13 FUEL PUMP115 A) tuse.
(To page 11 112)
(cont'd)
11-111
.f,

PGM-FI System
Throttle Position (TP) Sensor (cont'd)
- The MIL hss been.eported on.- DIC P1121 i. stored.
Problem vedficatiod:1. Turn the ignition switch ON (ll).
2. Check the throttle position
with the scan tool.
ls TP *% or higher indicatedwhen the throftle is tullyopenod?
Intermittent tailure, ryttem i! OKrtthistimo.
I Pl 121 | The sca n tool indicates Diag nostic Trouble Code (DTC) Pl 121: Throttle Position (TP) lower than expected.
*: 11.8 {D16Y5 enginei12.9 {016Y7 engine)12.2 (D16Y8 engine)13.7 (816A2 engine)
I P1122 I The scan tool indicates Diagnostic Trouble Code (DTC) P1122: Throttle Position (TP) higherthan expected.
*: 16.5 {Dl6Y5, Dl6Y8 engine}16.9 (D16Y7 engine)16.5 (81642 engine)
- The MIL ha3 be6n repoJted on.- DTC Pl122 i. llorod.
P.oblom v6dfication:1. Turn the ignition switch ON (ll).
2. Check the throttle position
with the scan tool.
ls TP'70 or l€ss indicated whenthe throttle is fully closed?Intormitt6ot frilu.o, aFtom b OKat thb timo.
1 1-138

Primary Heated Oxygen Sensor (Primary- Fjq?S) (Sensor 1l
('99 - 0b Models exiept D16Y5 engine with M/T)
TheHeatedoxygensensors(Ho2S)detecttheoxygencontentintheexhaustgasandsigna|stheEcM/PcM'|noperation,
the EcM/pcM receives the signars from the sensor and varies the duration during which fuel is injected. To stabilize the
sensor,soutput,thesensornasaninternaIheater.ThePrimaryHo2S(sensorl)isinsta|ledinexhaustmanifo|d(D16Y8.
81642 engine: exhaust PiPe A)
SENSORTERMINALSVOLTAG€ (VI
HEATERTERMINALS
The scan tool indicates Diagnostic Trouble Code (DTC) P0131: A low voltage
Oxygen Sensor (HO2S) (Sensor 1) circuit
RICH+ AIR- - LEANFUELRATIO
problem in the Primary Heated
HEATER
- The MIL has been t€Ported on.- DTC P013'l is stored.
Problem veritication:1. Do the ECM/PCM Reset Pro-
2. Start the engine. Hold the
engine at 3,000 rpm wrth no
load (in Park or neutral) until
the radiator fan comes on
3. Check the PrimarY HO2S
lSensor 1) output voltage wath
the scan tool during accelera
tion using wide open throttle
lntermittont f.ilure, 3ystem i3 OK
at thi3 time. Check tor Poor con'
nections or loose wires el C123
{Primary HO2S, Sensor 1) and
ECM/PCM.
Does the voltage stay at 0 5 v
or less?
Check the fuel pressLlre (see Page11,109).
(To page 11 142)(cont'd)
11-141

Secondary Heated Oxygen Sensor {secondary HO2S) (Sensor 2l
*'t : D16Y8 engine*2:'99 - O0 m;dels except D16Y5 engine with M//T
The scan tool indicates Diagnostic Trouble Code (DTC) P0137: A low voltage problem in the Secondary Heated
Oxygen Sensor (Secondary HO2S) (Sensor 2) circuit'
SECONDARY HO2S ls.n.ot 2),rP CONNECTOR (C125, C782')
Wire side oI temale terminals
(cont'd)
1 1-153
- Tho MIL has been reported on- DTC P0137 is stored.
Problem verification:1. Do the ECM/PCM Reset Pro
cedure.2. Start the engine. Hold the
engine at 3,000 rpm wlth no
load (in Park or neutral) until
the radiator fan comes on
3. With the scan tool, check the
Secondary HO2S (Sensor 2)
output voltage at 3,000 rPm
lntermittent frilure, sYdem is OK
at this tim6. Check for Poor con'
nections or loolo wir.3 at C131t(locatod undor right.ido of desh)'
C432. {located under middle of
dashl, cl25 lc782lr {SecondaryHO2S) tsensor 2l .nd ECM/PCM.
Does the voltage staY at 0.3 V
or less?
Ch6ck tot a sho.t in the S€condery
HO23:'1. Turn the ignition switch OFF.
2, Disconnect the SecondarY
HO2S lSensor 2)4P connector.
3. Start the engine.
4. Check the SecondarY HO2S
lsensor 2) output with the scan
tool,
Check tor a short in the wire
{SHO2S linel:1. Turn the ignition switch OFF.
2. Discon n ect tho EcM/PCM
connector D {16P) {A (32P))*'
3. Check for continuity between
the SecondarY H02S (Sensor
2) 4P connector terminal No 1
and body ground.
R€pair short in tho wire bstwoen
ECM/PCM lD14 (A231*'| and
Secondarv HOzS (Sensor 2).
Substitute a known-good ECM/
PCM and recheck lf 3ymptom/
indicalion go€s awaY, tePltco
the oiigin.l ECM/PCM.

PGM-FI System
Secondary Heated Oxygen Sensor (Secondary HO2S) {sensor 2l
[FO13a]l The scan tool indic€tes Diagnostic Trouble Code {DTC) P0139: A slow response probtem in the Secondary Heated- Uxygen Sensor (HOzS) (Sensor 2) circuit.
1 1-156
- The MIL has been reported on.- DTC P0139 is stored.
Problem verification:1. Do the ECM/PCM Reset Pro-
2. Start the engine. Hold theengine at 3,000 rpm with noload {in Park or neutral) untilthe radiator fan comes on.3. With the scan tool, check theSecondary HO2S (Sensor 2)output at 3,000 rpm.
Intermiftent failure, system i! OKat this tims. Check for pool con-nections or loos6 wiles at C131.{located undor ght lide of dash),C432' (locrted under middle otd.shl Cl25 (C782lr (SocondaryHO2S) (Sonsor 2) and ECM/FCM.
Does the voltage stay within0.3 - 0.6 V for two minutes?
*: D16Y8 engine

PGM-FI System
a
a
Heated Oxygen Sensor (HO2S) Heater
('96 - 98 Models,'99 - 00 D16Y5 engine with M/T) (cont'dl
PRIMARY HO2S {SENSOR 1I 4P CONNECTOR{c1231SECONDARY HO2S {SENSOR 2} 4PcoNNECTOR 1C125)r
r-l --'1
ll i2l
f;T;ttcl|BLK/ &)YELI Y
Wire side of fomale lerminals
SECONDARY HO2SISENSOR 2) 4P CONNECTOR{c78ilf
IBLK/WHT)
Wire side of lemale terminals
(From page 11-157)
Wire sid€ ot temale terminals
SO2HTC(BLK/WHTI* PO2SHTC{BLK/WHTI
*: P0141*+: Dl6Y8 engine
11-158
(From page 11-157)
Check tor an op6n or 3hoft in thewire {lGl lin6):Measure voltage between theHO2S 4P connector terminals No.3(D16Y8 engine: No. 4) and bodyground.- Repair open or shon in thewire between Primary HO2Slson.or 1), {No. 15 ALTERNA-TOR SP SENSORI (7.5 Al fuseand Secondary HO2S, Sonsol2t,.- Replace the No. 15 ALTERNA-TOR SP SENSOR 17.5 A) tuse.Check for an open in the wireIPO2SHTC, SO2SHTC' linel:1. Turn the ignition switch OFF.2. Reconnect the HO2S 4P con-nector.3. Disconnect the ECM/PCM con-nector A (32P).
4. Turn the ignition switch ON (ll).
5. Measure voltage between theECM,/PCM connector terminals46 and 410 {A5 and A10)*.
Ropail opan in the wire b€twoenECM/PCM lA6, A5l* and HO2S{Primary, Secondary+1.
ls there 0.1 V or less?
Substitute a known-good ECM/PCM and recheck. ll symptom/indication goes awry, repbcetho origin.l ECM/PCM.
ECM/PCM CONNECTOR A I32P)
so2sHrc ItBLK/WH0.J
pozsxtc E/
IBI-K/WHTI ^,-----{v}-|.=,|I
PG1IBLK}3u I JsTgT roll12r3t5t6Ittar920z2l 2321
25272A2i3o
Check tor a short in the wire{PO2SHTC. SO2SHTC* line):'1. Turn the ignition switch OFF.2. Disconnect the ECM/PCM con-nector A (32P1.
3. Check for continuity betweenthe ECM/PCM connector termi-nal 46 (A5)* and body ground.
Repair short in thg wire betwe€nECM/PCM lA6, A5*l .nd HO2S(P.im.ry, Socondary*).
Substitute a known-good ECM/PCM and recheck. It symptom/indicetion goes away, rophcethe original ECM/PCM.

PGM-FI System
Heated Oxygen Sensor (HO2S) Heater
('99 - 00 Models except D16Y5 engine with M/T)
(From page 11-159)
Substitute a known-good ECM/PCM and recheck. lf symptom/indication goes away, replacethe origin.l ECM/PCM.
(cont'dl
PRIMARY HO2S ISENSOR 1I 4P CONNECTOB{c123)SECONDANY HO2S ISENSOR 2} 4PcoNNECTOR (C125)*
-r--r ,
lr zl
-f-13 4llc'l L--r-J-r
relxr p1YELI Y
Wire side of temale terminals
SECONDARY HO2S(SENSOR 21 4P CONNECTOR{c782}rr
IG1 IBLK/WHT)
NO
Wire side of female telminals
ECM/PCM CONNECTORS
Wire side of female terminals
ECM/FCM CONNECTORS
*: P0141**: Dl6Y8 engine
1 1-1 60
Check for an open in the wires{lGl* line}iMeasure voltage between the primary HO2S 4P connector terminalNo. 3 (D16Y8 engine: No. 4) andbody ground.- Repeir open or shon in thewire between Primary HO2Slsensor 1), {No. 15 ALTERNA-TOR SP SENSOR) (7.5 A) fus€and Secondary HO2S, Sensor2t,.- ReDlace the No. 15 ALTERNA-TOR SP SENSOR {7.5 A tuse.
ls there battery voltage?
Check ,or an open in the wires(PO2SHTC, SO2SHTC' linel:1. Turn the ignition switch OFF.2. Reconnect the HO2S 4P con-nector,3. Disconnect the ECN4/PCM connector C (31Pi (ECM/PCM con-nector A (32P))i.
4. Turn the ignition switch ON (lli.
5. Measure voltage between theECM/PCM connector terminals82 and Cl 182 and AB)*.
Reprir open in the wirc betwo€nECM/PCM (Cl, A8i) and HO2S(Primary, Secondary+).
ls there 0.1 V or less?
(From page 11 l59i
Check tor a short in the wiresIPO2SHTC, SO2SHTC* linel:1. Turn the ignition switch OFF.2. Disconnect the ECM/PCM con-nector C (31Pi (ECM/PCM connector A (32P)i*.
3. Check tor continuity betweenthe ECM/PCM connector terminal C1 {A8)* and body ground.
Repai. short in the wire b€tweenECM/PCM lcl, A8.l and HO2S(Pdmery, Secondary*1.
Substitute a known-good ECM/PCM end recheck. lf symptom/indication goes away, replacethe o.iginal ECM/PCM.
Wire side of female terminals

PGM-FI System
Fuel Supply System
D017-il Th""""ntool indicates Diagnostic Troubte Code {DTC) p0171;Thefuet system istoo lean.
1P0172 | fne scan tool indicates Dlagnostic Trouble Code (DTC) P0172:Thefuel system istoo rich.
Description
By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.lf a malfunction has been detected during two consecutive trips, the MIL will come on and DTC P0171 and/or P0172 will bestored.
NOTE: lf some of the DTCS listed below are stored at the same time as DTC P0171 andlot P0172, ltouhleshoot those DTCSfirst. then recheck for DTC P0l7l andlot P0172.
P0106-8, P1128*3. *5, P1129*3 *5 MAP Sensor
P0135; Primary HO2S Heater
P0137. P0138: Secondary HO2S
P0'141: Secondary HO2S Heater
P0401: EGR Flow Insufficient*1
P0441: EVAP System Insufficient Purge Flow*6
P1259: VTEC System*,
P1491:EGR Valve Lift Insufficient*r
P1498: EGR Valve Lift Sensor Hjgh Voltage*r
*r: D16Y5 engines*': Dl6Y5, D16Y8, 81642 engine*3: '97 models*a:'96 modelsf 5: '98 - 00 models*6: '96 D16Y5 engine,'96 D16Y7 engine,'96 D16Y8 engine (sedan),'97 D16y5 engine,,97 D16y7 engine (coupe: KA, KC mo+els, sedan KA. KC, KL (DX) models. hatchback; all models),'97 D16Y8 engine (sedan: KA, KC models)
Possible Cause
DTC P0'171
loo lean
DTC P0172
too rach
Fuel Pump insuff icient f lovpressure
Fuel Feed Line clogged, leaking
Fuel Pressure Regulator stuck open
Fuel Filter clogged
Fuel Injector clogged, air inclusion
Gasoline doesn't meet Owner's Manual spec.
Primary HO2S (Sensor 1) deteriorated
MAP Sensor range/performance*.
EGR System malfunction (too much flow)*1
Valve Clearance
Exhaust leak
Fuel Pressure Regulator clogged, stuck closed
Fuel Return Pipe clogged
Fuel Injector leaking
Gasoline doesn't meet Owner's Manual spec.Primary HO2S (Sensor 1) deteriorated
MAP Sensor range/performance*a
EGR System insufficient flow*1
EVAP Purge Control Solenoid Valve leaking, stuck opened
Valve Clearance
11-164