1997 HONDA CIVIC IAT sensor

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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

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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)

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(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)

Transmission Assembly
l
,
{
Removal
@Make sure iacks and safoty stands are placad plop-
erly (3ee section l).
Apply parking braks and block rear wheels so car
will not roll off stands and fall on you while working
under il.
CAUTION: Us6 fonder cove6 to avoid damaging painted
sudaces.
Disconnect the negative (-) cable from the battery,
then the positive (+l cable.
Drain the transmission oil. then reinstall the drain
plug with a new washer (see page 13-47).
Remove the intake air duct and the air cleaner hous-
ing assembly (see s€ction 5).
Disconnect the back-up light switch connector and
the transmission ground wire.
Remove the lower radiator hose clamp from the
transmission hanger B.
L
8 x 1 .25 mm22Nm12.2kgl'm,
LOWER RADIATORHOSE CLAMP
16 rbtft)
13-48
7.
Bemove the wire harness clamps.
Disconnect the starter motor cables and the vehicle
speed sensor (VSS) connector.
8 x 1.25 mm8.8 N.m (0.9 kgf.m,6.5 tbtftl
STARTERMOTORCABLES
8. Remove the clutch line bracket and the slav6 cylin-
oer.
NOTE: Do not operate the clutch pedal once the
slave cylinder has been removed.
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Road Test
NOTE: Warm up the engine to normal operating tem peratu re (the rad iator fan comes on )'
1. Apply parking brake and block the wheels. Start the engine, then shift to E position while depressing the brake
Dedal, Depress the accelerator pedal and release it suddenly. The engine should not stall'
2. Repeat same test in E Position.
3. Test-drive the vehicle on a flat road in the E position. Check that the shift points occur at approximate speeds shown
in the table. Also check for abnormal noise and clutch slippage.
NOTE: Throttle position sensor voltage represents the throttle opening
a. Unbolt the PCM for road testing; refer to page 14-50.
b. Setthedigital multimeter to check the th rottle position sensor voltage between PCM terminals;
. '96 - 98 models: D1 {+) and A9 (-) or 422 (-}.
. '99 - 00 models: C27 (+) andB20t-) orB22{-}.
BACKPROBE ADAPTER
BACKPROBE SET07sAz - 001oq)A{two requiredl
DIGIIAL MULTIMETERlCommercially available)KS-AHM-32-003,or equivalenl
'96 - 98 Modelsr
Wire side ol temale terminals
PCM CONNECTORS
B t25Pl c (31P)
LG1 IBRN/BLK)
I (25P1c (31P}
A t32PtD (16P)
Wire side ol female terminals
'9!t - 00 Models:
1+113

Continuously Variable Transmission (CVTI
Special Tools ................ 14-194
Description .................... 14-195
Clutches/Reverse Brake/Planetary
Gear/Pulleys .......... 14-198
power Flow ..............,..... 14-200
Electronic Control SYstem(,96 - 98 Modets) ......14-203
Electronic Control System
('99 - oo Models) " 14-205
Hydraulic Control '....... 14-208
Hydraulic Flow .'..-.....'... '14-212
Park Mechanism .....-...'.' 14-222
Eleqtrical Systom
Component Locations'96 - 98 Models """"""' 14-224,99 - 00 Modets ............. 14-225
TCM Circuit Diagram ('96 - 98 Models) ............. 14-226
TCM Terminal Voltage/Measuring Condiiions ('96 - 98 Models) '.... 14-228
PcM Circuit Oiaqram{A/T Control System: '99 - 00 Models} ...--.... 14-230
PCM Terminal Voltage/Measuring Conditions('99 - 00 Models)
A/4 Control System .'.'...14-232
Troubleshooting Procedures ... . .... .....',........."' '14-234
Symptom-to-ComPonent Chart
Electrical System - '96 - 98 Models ......'..... '14-234
Electrical System -'99 - 00 Models ..'....-..-. '11-210
Electrical Troubleshooting
Troubleshooting Flowcharts('96 - 98 Models) """'11-242
Troubleshooting Flowchart
('99 - 0O Modets) ...... 14-265
Linear Solenoids/lnhibitor Solenoid
Test ......................... . ...... 14-29f
Drive Pulley/Driven Pulley/Secondary Gear
Shaft Speed Sensors
Replacement .........'...... .14-292
Start Clutch Control
Start Clutch Calibration Procedure ....... ....,. 14-293
Hydraulic SYstem
Symptom-to-ComPonent Chart
Hydraulic System '.'.......14-294
Road Test ............................ 14-296
Stall Speed
Test......................... ...... 14-294
Fluid Level
Checking/Changing ....... 14-299
Pressure Testing ................. 14-300
Lower Valve BodY AssemblY
Replacement ..........,... 14-302
ATF Filter
Removal/lnstallation ..... 14-303
Transmission
Transmission
Removal ........... . 14-304
lllustrated Index
Transmission/Lower Valve BodY
Assembly ................. 14-308
Transmission Housing/Flywheel Housing ... 14-310
End Cover/f ntermediate Housing ..........'.'.... 14-312
Transmission Housing/Lower Valve Body Assembly
Removal ..........'.... .. " 14-314
Transmission Housing/Flywhesl Housing
Removal ................. ........ 1+316
End Cover/lntermediate Housing
14-318Removal .........,...............
Manual Valve Body
Disassembly/lnspection/Reassemblv .'.'.'..... 1 4-320
Forward Clutch
lltustrated Index ........................................ 14-321
Disassemblv .................. 14-322
Reassemblv , ,, . ',','......14-324
Secondary Gear Shaft
25 x 35 mm Thrust Shim Selection ..'.'....-... 14-324
Differential
lllustrated lndex ...,.....................,.,...-.-.-...'... 14-329
Backlash Inspection .-....14-329
Bearing Replacement ......'........'....'... ....'... 14-330
Differential Carrier Replacement ........'........ 14-330
Oil Seal Removal ........... 14-331
Oil Seal Installation/Side Clearance ....... . . 14-331
Flywheel Housing Input Shaft Oil Seal
Replacement .....,.... ...'.'.. 14-333
Transmission Housing Bearings
Driven Pulley Shaft Bearing
Replacenient ...................'. . ...................'.. 14-334
Secondary Gear Shaft Bearing
Reolacbment ...................... . .......... . ........ 14-335
Flywheel Housing Beating
Secondary Gear Shaft BearingReo1acement..................,........................... 14-335
Ring Gear Bearing
Replacement......... ........ 14-336
Control Shaft Assembly
Removal/lnstallation ....................'........... 14-336
Transmission
Reassembly .................. 14-338
Flywheel/Drive Plate .. . ...... . ...... ... . ....-.....'.'...14-341
Transmission
lnstalation ..................... 14-348
Cooler Flushing .'......... 14-352
shift cable
Removal/lnstallation....'........." """ 14-354
Adjustment .......'........ 14-355
Shift Lever ........................,. 14'356
Shift Indicator Panel
Adjustment ................ 14-357
ATF Cooler/Hoses
lnsta llation ......,,...... .... 14-357