1999 HONDA CIVIC c 131

Check the ECM input vottage {lP-/
VS- lino):1. Turn the ignition switch OFF.
2 Turn the ignition switch ON (ll)
3. Measure voltage between
ECM connector terminals C24
Ch.ck the ECM:
1. Turn the ignition switch OFF
2. Disconndct ECM connector C
{31P){rom the ECM.
3. Check lor continuity between
body ground and ECM con
nector terminal C24
ls there more than 0.5 V?
- Repair open in the wire
betw€en ECM {C2{l and Pri-
ma.y HO2S {S€nsor 1 l.- Substitute a known-good ECM
and recheck. It symptom/indi
cation goes away. replace the
odginal ECM.
Check to. r short in the wi.e {lP-/
VS- lin6l:1. Disconnect the 8P connector
from the Primary HO2S lsen-
sor 1).2. Check tor continuity between
body ground and ECM connec-
tor terminal C24
Ropair short in the wire bstween
the Primary HO2S lsensor 1) and
ECM (C24).
Check the ECM output voltage
{VS+ linel:N4easure voltage between ECM
connectorterminals C25 and D11.
Check for a short in the wire (VS+
line):1. Turn the ignition switch OFF.
2. Disconnect ECM connector C
{31P) Irom the ECM.
3. Check {or continuity between
body ground and ECM con
nector terminal C25.
ls there mote than 0.5 V?
ECM CONNECTORS
lFrom page'11-146)c (31PlD {15P)
tP-/vs- tREolfemale termrnals
sG2(GRN/BLKI
(cont'd)
11-147
I23a68910
111213la15t6'171622
232a25272a2930
O rP-/vs-:Z taeot
,l23a55I910
1112131a151617t822
232125212AE30
0) {REDr
23a518910
l11213ta'15't6171822
2321E272A2930
[]) vs*I rwsrt
(To page 11- 148)(To page 11 148)

PGM-FI System
Primary Heated Oxygen Sensor (Primary HO2SI (sensor l)
(Dl6Y5 engine with M/T) (cont'd)
(From page 1l-147)(From page 11 147)
(To page 11 149)
{GRN/BLK}
(GRN/8I-K}
(To page 11-149)
11-148
Substitute a known-good ECMand rechock. tf symptom/indicr-tion goes away, replace the origi-nalECM.
Check for a short in the wire llP+lin6):1. Disconnect the 8P connectorIrom the Primary HO2S (Sen-
sor 1).2. Check tor continuity betweenbody ground and ECM connec-tor terminal C25.
Repair short in the wiro botweenthe Primarv HO2S {Sensor 1} andECM {C25}.
Replace th€ Primary HOzS {Sen-sor 11.
| 2 3ra1a9to
tl 12t516111a
p ffi;r, w''.""i0"or.I lemate lerml
ls there more than 5.0 V?check the EcM:1. Turn the ignition switch OFF.2. Disconnect the 8P connectorfrom the Primary HO2S (Sen-
sor 1).3. Turn the ignition switch ON (ll).4. Measure voltage between ECN4connector C25 and D11.
ls there more than 5.0 V?
Check the ECM input voltage llP-/vS-linel:1. Start the engine. Hold theengine at 3,000 rpm with noload (transmission in neutral)untilthe radiator fan comes on,then let it idle.2. Measure voltage between ECMconnector terminals C24 andDt1.
Subslitute a known-good ECMand rgcheck. It symptom/indica-tion goes away, repl.ce the origi-nal ECM.
ls there 2.6 2.8 V?Check th6 ECM output voltage(VS+ linel:Measure voltage between ECMconnector terminals C25 and D11.
7a9t0It 12t3t6'11ta
VS+{WHT}sG2
235
,9 ,101l12
l3'tat515
1 2i35a9t0't2'ttt5ttrl22
VS+{WHT)sG2
23
6lt9ll1315

(From page 11 148)(From page 11'148)
Roplac€ th€ Primary HOzS (Sen'
sor 11.ls there lessthan 2.8 V?
Substitute a known-good ECM
and recheck. lf symptom/indica'
tion goes awav, replace th€ odgi'
nalECM.
Check the ECM oulput voltage
(lP+ linel:Measure voltage between ECM
connector terminals C23 and D11
Substitute a known-good ECM
and recheck f symptom/indica-
tion goes awaY, replace the origi_
nal ECM.
ls there more than 0.4 V?
Check the ECM:1. Turn the ignition switch OFF.
2. Disconnect ECM connector C(31Plfrom the ECM.
3. Check for continuity between
body ground and ECM con-
nector terminal C23
Check fot an oPen in tha wire
llP+ linel:1. Turn the ignition switch OFF.
2. Disconnect the 8P connoctor
from the Primary HO2S (Sen-
sor'l).3. Check for continuity between
the PrimarY HO2S (Sensor 1)
8P connector terminal No. 7
and ECM connector termrnal
c23.
Repair open in the wire belween
ECM {C231 and Primary HO2S
{Sensor 11.
Substitute a known_good ECM
and r6check. lf symPlom/indica'
tion goos away, replace the odgi-
nalECM.
Check for a short in the wire llP+
line):1. Disconnect the 8P connector
from the Primary HO2S {Sen'
sor 1),2. Check for continuity between
body ground and ECM con-
nector terminal C23.
Repair short in lhe wire belween
the Primary HO2S (Sensor 'l) dnd
ECM {C23).
Replace the Primary HO2S (Sen'
sor 1).
sG2(GRN/BLKI
Wire side offemale termanals
PRIMARY HO2S(SENSOR 1l8PcoNNECTOR lC1a5l
lP+(BLK)
Wire side of
female termrnalsof femaleterminals
NO
(cont'd)
123a68910
111213141516171822
2125a30
I lP+
6) tBrK)
ECM CONNECTOR C {31P}
23a67II10
1112131l15161118,422
232a25A30
A lP+Ij/ IBLK)
11-149

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

tFo135l
iPol4tl
Heated Oxygen Sensor (HO2SI Heater
('96 - 98 Mbdels,'99 - 00 Dl6Y5 engine with M/Tl
*: p0141 (To page 11-158)**: D'16Y8 engane
The scan tool indicates Diagnostrc Trouble code (DTC) P0135: An electrical probl€m in the Primary Heated
Oxygen Sensor (Primary HOiS) (Sensor 1) Heater system (Except D16Y5 engine with M/T)'
The;can tool indicates Diagnostic Trouble code (DTC) P0141: A problem in the secondary Heated oxygen sensor
(secondarv HO2S) (Sensor 2) Heater circuit.
PRIMARY HO2S (Son.or 1l aP CONNECTOR
SECoNDARY HO2S tsensor 2l ilP CONNECTORT
Terminal side of male terminals
PRIMARY HOzS (SENSOR 1) 4P CONNECTOR ICl23I
SECONDARY HO2S ISENSOR 2) 4P CONNECTOR {C125I*
PO2SHIC, SO2SHTCIBLK/WHT)
Wire side of female terminals
SECONDARY HO2S ISENSOR 2),tP CONNECTOR 1C782)'*
so2sHTC{BLK/WHT)
Wire side oI female terminals
I(cont'd)
11-157
- The MIL h.s boen Jeponed on.- DTC P0135, and/or Polal .re
stoled.
Problem verificationl
1. Do the ECM/PCM Reset Pro-
ceduae,2. Start the enginelniermittent tailura, sYttam i! OK
at thi3 time, Chsck for Poor con'
neciion3 or loose wilG3 at
C131** (locat.d undo. right sido
ot dashl, C{32** (loc.ted under
middle ol dashl, C123 (PrimarY
HO2S. Sansor 1) C125 lc782l*r
{Socondery H02S, Sonsor 2l'
and EcM/PcM.Check for an open or 3hort in tho
HO25:1. Turn the ignition switch OFF.
2. Disconnect the HO2S (Primary
or Secondary*) (Sensor 1 or
Sensor 2) 4P connector'3. At the Ho2s side, measure
resistance between the HO2S
4P connector terminals No. 3
and No.4.
ls there 10 - 40 0?
Check for continuity between
body ground and the HO2S 4P
connector terminals No. 3 and
No.4 individually
Chock for an oPen ot short in tho
wire |PO2SHTC, SO2SHTC* linol:
1. Turn the ignition switch ON (ll).
2. Measure voltage between the
HO2S 4P connector terminalsNo.3 and No.4.
(To page 11'158)

IHeated Oxygen Sensor (HO2S) Heater
i'ss - oo Mb-dels except D16Y5 engine with M/Tl
The scan toot indicates Diagnostic Trouble Code (DTC) P0135: An electrical problem in the Primary Heated
Oxygen Sensor (Primary ttOiS) (Sensor 1) Heater system {Except D15Y5 engine with M/T)'
The
-scan tool indicates Diagnostic Trouble Code (DTC) P0141; A problem in the Secondary Heated Oigen Sensor
(Secondarv HO2S) {Sensor 2) Heater circuit
Fo13sl
Fol11l
lntermiftent failuro, sYstom b OK
at thit limo. Ch6ck lor Poor oon'
nectiont or looso wita! at
C131'* {loc.tod und.t right ido
ol drshl, C432'* (located undel
middlo of dashl, C123 (PrimarY
HOzS, Sensor 1) C125 (Ct82lr'
(socondary HO2S, Sensor 2)t
.nd ECM/PCM.
PRIMAFY HO2S ls.n.or ll rrP CONNECTOR
SECOITIDARY HO2S (Srn.ol21 4P CONNECTOR'
Terminal side of male terminals
PRIMARY HO2S {SENSOR 1} ilP @NI{ECTOR lc123l
sEcoNDARY HO2S ISENSOR 2) aP @NNECTOR (C125)'
3l-, l-tl-t Fo2sHrc. so2sHrc
ver.t l ^-1 .'l {BLK/wHrl
11 '!'l-l
| --=- Iu----{v)'---..-'
Wire side of {emale terminals
SECO'TIDARY Ho2S (SENSOR 2,
4P CONNESTOR {C7&llt'
so2sHTc(BLKnflHTlIBLK/WHT)
(cont'd)
1 1-159
Wire side oI female terminals
r: p0141 {To page 11-160}**: D16Yg engine
- The MIL has been reponed on.- DTC P0135. and/or P0141 are
storod.
Problem vorification:1. Do the ECM/PCM Reset Pro-
cedute.2. Stan the englne.
Chock foi an open or short in the
HO25:1. Turn the ignition switch OFF
2. Disconnect the HO2S (Primary
or Secondary*) lSensor 1 or
Sensor 2) 4P connector'
3. At the H02S side, measure
resistance between the HO2S
4P connector terminals No. 3
and No.4.
ls there 10 - 40 n?
Check for continuity between
body ground and the HO2S 4P
connector terminals No. 3 and
No.4 individuallY.
Check for an opon or short in lho
wire (PO2SHTC, SO2SHTC+ line):'1. Turn the ignition switch ON (ll).
2. Measure voltage between the
H02S 4P connector termlnalsNo.3 and No.4.
{To page 11-160}

PGM-FI System
Random Misfire
lFoioo l*u o, [FTioo l*' *' and
The scan tool indicates Diagnostic Trouble Code (DTC)
P0300*5 or P1300*3 *1 and some of P0301 - P0304:Random misfire.Description
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensorwhich is attached to the crankshaft.
lf misfiring strong enough to damage the catalyst is detected. the MIL will blink during the time of its occurrence, and DTCP0300*5 or P1300*3'*' and some of DTCs P0301 through P0304 will be stored. Then, after misfire has ceased, the MIL willcome on.
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTCP0300*5 or P1300*3 *a and some of DTCS P0301 through P0304 will be stored.NOTE: lf some of the DTCS listed below are stored at the same time as a misfire DTC. troubleshoot those DTCS first, thenrecheck for the misfire DTC.
P0106*4. P0107. P0108, P1128*3 *5, Pl129*3 *5; MAP sensorP0131. P0132: HO2S
P0171, P0112i Fuel metering
P0401, P 1491, P1498: EGR svstem*1P0505: ldle Control SystemP1253: VTEC System*,P1361, P1362: TDC sensorP1381, Pl382: CYP sensorP1508: IAC valve
Possible Cause. Fuel pump insufficient fuel pressure, amount of flow. Fuel line clogging, blockage, leakage. Fuel filter clogging. Fuel pressure regulator stuck open. EGR system malfunction*1. Distributormalfunction. lgnition coil wire open. leakage *l: D16Y5 engine. lgnition control module malfunction *2: D16Y5, D16Y8, Bt6A2 engine. MAP sensor range/performance, poor response*r *3: '97 models. Valves carbon deposit *4;'96 models. Compression low *5: '98 - 00 models. IAC valve malfunctionr.. VTEC system malfunction*,. Fuel does not meet Owner's Manual spec., lackoffuel. HO2S. HO2S circuit
Troubleshooting
By test-driving, determine the conditions during which misfire occurs, Depending on these conditions, test in the orderdescribed in the table below.
Possible
- --^ ---
rage
causeEGR*1
system
Crankshaft
position (CKP)
sensor
Fuel
pressure
Distributor and
lgnition wirestcMClearance
tAc
ValveMAP
sensor
section 611-230,
231section 23section 23section 611-19411
Only low rpm and
loado@@oo
Only accelerating@o@@
Only high rpm and
toaooo@
Not specificoo@
NOTE: lf misfire doesn't recur, some possible causes are fuel that doesn't meet owne/s manualspec, lack of fuel, carbon deposits on spark plug, etc.
1 1-1 66
I
P0304