1999 HONDA CIVIC engine fan

\
lTo420l Th" """n toot indicates Diagnostic Troubte code (DTc) p0420: catatyst sysrem efficiency below threshold.
Description
This system evaluates the catalyst's capacity by means of the Ho2s {Primary and secondary) output during stable driving
conditions. ll deterioration has been detected during two consecutive driving cycles. the MIL comes on and DTC P0420 will
be stored.
NOTE: lf some of the DTCS tisted below are stored at the same time as DTC P0420, troubleshoot those DTCS first. then
recheck for DTC P0420
P0137, P0138: Secondary HO2S (Sensor 2)
Po14'1:Secondary H02S {Sensor 2) Heater
Possibl€ Cause
. TWC Deterioration
. Exhaust system leakage
Troubleshooting Flowchart
I
The MIL has been reported on.
DTC P0420 is stored
Problem verilication:1. Do the ECM/PCM Reset Proce
dure.2. Start the engine Hold the
engine at 3,000 rpm wath no
load {in Park or neutral) until
the radiator fan comes on.
3. Connect the SCS service con
4. Test drive 40 - 55 mph for
approx, two minutes Then
decelerate for at least 3 sec_
onds with the throttle com'pletely closed- Then reduce
the vehicle speed to 35 mph,
and try to hold it until the
readiness code comes on
Intermittent Iailure, system is OK
at this time.ls DTC P0420 indicated?
Check the TWC {see section 9l
lf necessary, replace the TwC

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

\JExhaust Gas Recirculation System (D16Y5 engine with M/T)
M/T:
EGR VALVE 6P CONNECTOB (C14'rl
G10lIBLK}
1
a
PNK
IE.EGRI
Wi16 side of male terminals
I
sG2{GRN/BLK}
vcc2{YEL/BLU)
- Th6 MIL ha3 b€on reponed on.- DTC Pl,{tl is 3tored.
Prcblem verification:1. Do the ECM Reset Procedure.
2. Connect the SCS service con_nector.3. Start the engine. Hold the
engine at 3,000 rpm with no
load (transmission in neutral)
untilthe radiator fan comes on.
4. Drive the vehicle on the road
for approx. 10 minutes. Try to
keep the engine speed in the
1,700 - 2,500 rpm range.
lnlermittont tailure, svalem is OK
at thi3 tim6. Check foi Poor con'
nections or looso wiro3 at Cl/K
IEGR valvsl and ECM.
ls DTC P1491 indicated?
Check tor a malfunction in the
EGR valv6:1. Turn the ignition switch OFF.
2. Disconnect the EGR valve 6P
connector.3. Stanthe engine and let it idle
4. Measure voltage between the
EGR valve 6P connector termi'
nals No.4and No.6.
Check the EGR valve:1. Turn the ignition switch OFF2. Turn the ignition switch ON lll).3. Measure voltage between theEGR valve 6P connector termi
nals No.2 and No.3.
ls there battery voltage?
Substitute a known-good ECM
and recheck. It symptom/indica_tion goes away, replace th€ origi-
nal ECM.
ls there approx.5V?
(To page 11-262)

\J
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,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)

\
\
(From page 11-284)
\(cont'd)
11-285
EVAP PURGE CONTROL SOI.INOID
VALVE 2P CONNECTOR IC114I
Wire side otfemaleterminals
?,
I,l,lil?"",,,u
EL,TWYEL)
Check the EVAP pirrge controlsolenoid valvei1. Disconnect the 2P connector
lrom the EVAP purge control
solenoid valve.
2. Ouickly raise the engine speed
to 3,000 rpm.
ls there vacuum?
InsDect vacuum ho56 routing.ll OK, replace the EVAP Purgecontrol solenoid valve.
Chock for a short in the wire(PCS linel:1. Turn the ignition switch OFF
2. Disconnect ECM/PCM connec'
tor A (32Pi.
3. Check for continuity between
the EVAP PUrge control sole
noid valve 2P connector termi
nal No.2 and body ground.
Check the vacuum when hot:
1. Turn the ignition switch OFF
2. Block the rear wheels and set
the parking brake.3. Jack up the front o{ the vehi-
cle and support it with safety
stands,4. Start the engine. Hold the
engine al 3,000 rpm wlth no
load (in Park or neutral) until
the radiator fan comes on, then
let it idle.5, Check for vacuum at the vac-
uum hose with transmissaonin gear (A/T in B Position,M/T in lst gear) after starting
the engrne.6. Ouickly raise the engine speed
to 3,000 rpm.
Reoair short in the wire botween
the EVAP purg€ cor|t]ol solenoid
valve and the ECM/pcM lA15l.ls there continuity?
Substitute a known-good ECM/
PCM and recheck. lf sYmPtom/indication goes eway. repl.c€ the
original ECM/PCM.
Check the EVAP Purg€ control
solenoid valve:1. Turn the ignition switch OFF
2. Disconnect the 2P connector
from the EVAP Purge control
solenoid valve and warm lt
up to normal operating tem_perature again if necessary
3. Stan the engine.4. At the harness side, measure
voltage between the EVAP
Purge control solenoid valve
2P connector terminal No. 1
and No. 2 with the transmission in gear (A,/T in E Posi-tion, M/T in 1st gear).
In3pect vacuum ho3€ touting.
ll OK, replace EVAP Purge con-
lrol aolenoid vtlv€.
Check lo. an open in the wire
llGl linel:At the harness side, measure volt
age between the EVAP Purge con-
trol solenoid valve 2P connectorterminal No. 1 and body groundRepeir open in tho wire between
EVAP purge conttol solenoid valv€
and the No. 15 ALTERNATOR SP
SENSOR (7.5 A fu3e
IBLK/YELI
lTo page 11 286i(To page 11-286)

Emission Control System
Ch€ck the EVAP purge controlsolenoid valv6:1. Disconnect the 2P connectorfrom the EVAP purge controlsolenoid valve.2. Ouickly raise the engine speedto 3,000 rpm.
Insped vacuum hose routing.lf OK. roplace the EVAP purge
control solonoid valve.
Chock tor r short in the wir€
{PCS line):1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P).
3- Check tor continuity betweenthe EVAP purge control sole-noid valve 2P connector termi-nal No. 2 and body ground.
Check the vacuum when hot:1. Turn the ignition switch OFF.2. Block the rear wheels and setthe parking brake.3. Jack up the lront of the vehi-cle and support it with safetystands.4. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutrali until
the radiator fan comes on, thenlet it idle.5. Check for vacuum at the vac-uum hose with transmissionin gear (A/T in E position,
lvl/T in 1st gear) after startingthe engine.6. Ouickly raise the engine speedto 3,000 rpm.
Rooair shoft in the wire belwegnthe EVAP pulg6 control solenoidvalvs and tho ECM/PCM {A61.ls there continuity?
Substitute a known-good ECM/PCM and rech6ck. lt 3ymptom/indicrtion 90e3 rway, r6plac6 th€o.iginal ECM/FCM.
Check th€ EVAP purge controlsolenoid valve:1. Turn the;gnition switch OFF.2. Disconnect the 2P connectorfrom the EVAP purge controlsolenoid valve and warm itup to normal operating tem-perature again if necessary.3. Start the engine.4- At the harness side, measurevoltage between the EVAPpurge control solenoid valve2P connector terminal No. 1and No.2 with the transmis-sion in gear {A/T in E posi-tion, M/T in lst geari.
In3pect vacuum hoae routing.lf OK, repl.ce EVAP purge con-trol solonoid valve.ls there battery voltage?
Chock for an open in the wire(lG1 lina):At the harnoss side, measure volt-age beNveen the EVAP purge con-trol solenoid valve 2P connectorterminal No. 1 and body ground.
Repair open in the wire b€lwe€nEVAP purge contrl 3olenoid valv6and lhe No. 15 ALTERNATOR SPSENSOR 17.5 A, fu3e.
ls there battery voltage?
Evaporative Emission (EVAPI Controls (cont'dl
(From page 11-289)
(To page 11-291)
11-290
IJ
EVAP PURGE CONTROL SOLENOIDVALVE 2P CONNECTOR IC114I
PCS
IRED/YEL)
temaletermrnars
of
PCS(RED/YEL)
tGlIBLK/YEL)
{To page 11 291)

Electrical Troubleshooting ('96 - 98 Models)
Troubleshooting Flowchart - Lock-up Control System
NOTE: Record all freeze data before vou troubleshoot.
Possible Cause
Faulty Lock-up cont.ol system
NOTE: Do not continue with this troublesnoonnoother DTCS have been corrected.until the causes of any
. OBD ll Sc6n Tool indicatG Codem7{0.. Self-diagnosis E indicator lightindicates Code 40.
Check tor Another Code:Check whether the OBD ll scantool or the E indicato, lightindicates another code.
Perform lhe Troublo3hooiingFlowchart tor the indicatedCode(s). Recheck for cod. P07il0lilol aftor iroubl€3hooting.
Does the OBD ll scan tool orthe E indicator light indicateanother code?
Tast Line Pressure:Measure the line pressure (seepage 14-119 and 14-120).
Repair tho hydreulic aystem a3necessary {3ee page 14-119).
Replace the Lock-up ControlSolenoid Valve Assembly andR6check;1. Beplace the lock up controlsolenoid valve Ay'B assembly(see page 14-105).2. Turn the ignitaon switch OFFand reset the PCM by removing the BACK UP (7.5 A) fusein the underhood fuse/relaybox for more than 10 seconds,3. Using the scan tool, check tobe sure that the engine coolant temperature is in 176'F(80'C) and above.4. Drive the vehicle at 55 mph(88 km/h) constantly for morethan one minute.5. Recheck for code P0740 (40).
Does the OBD ll scan toolindicate code P0740 {40)?The systom k OK at this time.
l'.
14-74

Troubleshooting Flowchart - Lock-up Control System
NOTE: Record all freeze data before vou troubleshoot.
Possibl€ Cause
Faulty Lock-up control sy3tem
NOTE: Do not continue with this troubleshootingother DTCS have been corrected.until the causes of any
OBD ll Scan Tool indicates Codem14/J.S€lf-diagnosis .D4l indicalor lightindicates Code 40.
Check for Another Code:Check whether the OBD ll scantool or the :E indicator lightindicates another code,
Perform the TroubleshootingFlowchart tor the indicatedCodels|. Rocheck to. code P0740(40) .fter troublBhooting.
ooes the OBD ll scan tool orrhe E indicator light indicateanother code?
Test Line Pressure:Measure the line pressure (see
page 14 119 and 14-120).
Repair the hydrrulic sy3tem asn6c6ssary (see page 14-1191.ls the lane pressure within theservice limit?
Replace the Lock-up ControlSolenoid Valve Assembly andRecheck:1. Replace the lock-up controlsolenoid valve A/B assembly(see page 14-105).2. Turn the ignition switch OFFand reset the PCM by removing the EACK UP (7.5 A) fusein the underhood {use/relaybox for more than 10 seconds.3. Using the scan tool, check tobe sure that the engine cool-ant temperature is in 176'F(80'C) and above.4. Drive the vehicle at 55 mph(88 km/h) constantly for morethan one minute,5. Recheck for code P0740 {40).
Does the OBD ll scan toolindicate code P0740 (40)?The svstem i3 OK .t this time.
14-99