speed sensor circuit HONDA CIVIC 1998 6.G Workshop Manual

!
Fuel and Emrsslons
SoecialToofs .....,...."..,. 11-2
Component Locations
lndex ....................., ......... 11-3
Svstem Description
Vacuum Connections ................,,..,.. ......... 11-12
Electrical Connections ...............,.,.,... ....... 11-29
System Connectors ........,.,.,.......................... 1 1-51
Troubleshooting
Troubleshooting Procedures ................. .. 11-81
Engine Control Module/PowertrainControl Module TerminalAfiangement ....,.,..... 11-88
Diagnostic Trouble Code Chart .................,., 11.97
How to Read Flowcharts .,.......................... . 11-103
PGM-Fl System
System Description ...... 11-10,1
Troubleshooting Flowcharts
Engine Control Module/PowertrainContlol Module ........ 11-107
Manitold Absolute Pressure Sensor .....'. . ... 11-115
fntake Air Temperatuie Sensor ..... . . ., . 11'121
Engine Coolant Temperatuae Sensol ........., 11-128
Throttle Position Sensor ...................,........... 11-132
Primary Heated Orygen Sensor (Sensor 1l ... 11-139
Secondary Heated Oxygen Sensor(Sensor 21.................................................... 1 1-153
Heated Oxygen Sensor Heater ...................,. 11-157
Fuel Supply System ...... 11-164
Random Mislire ......., ..11-166
Misfire Detected in One Cylindsr ................. 11-167
Knock Sensor .,.,............ 11-170
CKP/TDC/CYP Sensor ................................... 11'172
Vehicle Speed Sensor ...........,......,...,.,........... 1t-176
Barometric Pressure Sensor ...............,......... I 1-178
Electrical Load Detector,.,,............................ 1 1-179
CKF Sensor .................... 11-183
ECM/PCM Internal Circuit ............................. I 1-188
A/T Signal {TMA/TMBI .................................. I 1-189
ldle Control System
System Doscriplion ............ 11-190
Troubleshooting Flowcharts
ldle Control System ...... 11-192
ldle Air Control Va1ve .................................... I 1-19i1
Starter Switch Signal .................................... 1 1'202
Air Conditioning Signal ................................. 11'201
Ahernator FR Signal .................................... . 1 1-208
BrakeSwitch Signal ..................................... f 1"210
Power Sleering Prossure Switch Signal ......11-212
A/T Gear Position Signal ............................... 11-216
Clutch Swiich Signal ................................-.... 11-214
ldte Speed Setting . .............11-220
Fuel Supply System
Fuel Lines .,...................,.,.,.,11-221
Fuef Tube/Ouick-Connect Fittings ..........,.,........ 11 -227
System Description ....'.... 11-230
Fuel Pressure .......,.,,........... 11-230
Fuef fniectors ......................11-232
Fu€f Pressure Regulator .....,.......................'...,. 11-231
Fuef Fifter ............................11-235
Fuel Pump .............'.......'.... 11-236
PGM-FI Main Relay .............11'237
Fuel Tank ................ ....,...'.'.' 11'211
Intake Air System
System Description ....-.-.....11-243
Air Cfeaner ...........,......."". .11-211
Throttle Cable .....................11-211
Throttfe Body ........ ..'... . . .,.11-211
Fuel Iniestion Air Control System ,.,.,....-........... 11-250
Emission Control System
System Description .-..........11-252
Taifpip€ Emission ...............11-252
Three Way Catafytic Convert€r ............,.,,.,.,.,.... 11 -252
Exhaust Gas Racirculaiion System ...,.,,,,.,.,.,.,,. 11'254
Positive Crankcas€ Ventilation System .... . . .. 11-266
Evaoorative Emission Controls ..................,,..,.,. 11 -267

Probable Cause List lFor th€ DTC Chart, see page 11-971*: '99 - 00 models
Probable GausePageSystem
11 1-107Engine Control Module (ECM)/Powertrain Control Module (l'uM)
PGM-Fl main relay
l^^iti^n cwetam
211-230,231
3't't-237
Section 23
51'1-172,183Crankshaft Position/fop Dead Center/Cylinder Fosltlon sensor clrculr' Lr\F selrsor
circuit
Intake Air Temperature (lAT) sensor circuit
ldle Air Control (lAC) Valve
ldle speed adjustment
Throttle bodY
Throftle cable
Manifold Absolute Pressure (MAP) sensor
Throftle Position (TP) sensor
Barometric pressure (BARO) senso'
Mf g"a, po"ition signal (see page 11-216) or clutch switch signal
Brake switch signal
Air Cleaner
lntake air pipe
Three Way Catalytic Converter (TWC)
Evaporative emission (EVAP) control
Contaminated fuel
ORVR vent shut valvs
't1-124
71 1-194
I11-220 - 223
11-241
'1011-244
1111-115
1211-132
13't1-178
14Section 14. 11-218
1511-210
16't1-244
1811-252
1911-261
20
21*11-296
(cont'd)
11-85

Troubleshooting
Engine/P_o_wgrtrain Control Module Terminal Arrangement('96 - 98 Models '99 - 00 Dt6y5 engine with M/T) tc'oniOi
ECM/PCM CONNECTOR C {31PI
1
CKFP
2
CXPPTDCPa
ACS
5
sTs
7
scsII
rMA
10
v8u121314t51517
ALTF
TE
vss23lP+
21252930
TMA
Wire side of female terminalsECM/PCM CONNECTOR C (31PI
NOTE: Standard baftery voltage is 12 V
'1: USA modelr2rA,.T (D16Y7, O16Y8 ensane)*3: CVT (O16Y5 engine)*4: Ay'T and O16Y7 engine'5: Excepl A./T snd Dl6Y7 engine16: Ay'T (D16Y8 ensine){7: CVT (Dl6Y5 eosine) and O16Y8 enoine"8: 96 Dl6Y8 engine (coupe),'97 D16y8 engine (coupe: atl:ed-9I t!!rnodelr,'98 D16y5 ensine,,98 D16y8 e;sine.D16Y5 lM/T) ensine
1-90
19: D16Y5 engine'10: M/T (Dl6Y5 engine)*11r Except M/T 116Y5 engine)*12: D16Y5, D16Y8 engine*13: Dl6Y8 enqine*14: O16Y7 enginei15: '-97 O16Y7 engjne (coupe: KL modet, sedan: KL (LX) modet),'98D16Y7 enqine'99 - 00
1
To.min!lnumberWiracoloaTorminalnameDo6criptlonSignal
1BLU/REDCKFP (CKF SENSOR P SIDE)Detects CKF sensor.With engine running: pulses2BLUCKPP (CKP SENSOF PSIDE)Detects CKP sensor.With engine running: pulses3GRNTDCP {TDC SENSOR PSIDE}Detects TDC sensor,With engine running: putses4YELCYPP (CYP SENSOR P SIDE)Detects CYP sensor.With engine running: pulses
5BLU/FEDACS {Tr'C SWITCH SIGNAL)Detects ,ay'C sw;tch signat.With Iy'C switch ONr 0 VWith Ay'C switch OFF: batrery vottage
6BLU/ORNSTS (STARTER SWITCHSIGNAL)Detects staner swilch signal,With staner switch ON ltlt): batery vohageWith staner switch OFF: 0 V
8RNSCS (SERVICE CHECKSIGNAL)Detects service check connector signal{the signalcausing a OTC indicationlWith the connector connected: O Vwith the connector disconnected: about 5 vor battery voltageLT 8LUK,LINE (DLC)Sends and receives scan iool signal,Wirh ignition switch ON { ): about 5 V
9+3GRYDat6 communication with TCM: ECMcontrol ctat6 outputWith ignition switch ON (tt):putses
10WHT/BLUVBU (VOLTAGE BACK UP)Power source forthe ECM/PCMcontrol circuit. Power sourc€ lortheDTC memory
Battery voltage at all times
11WHT/REDCKFM {CKF SENSOR MSIDE)Ground tor CKF sensor signal.
12CKPM (CKP SENSOR MSIDE)Ground for CKP sensor s;gnat.
REDTDCI\4 (TDC SENSOR MSIDE)Ground for TDC sensor signal.
14BLKCYPM (CKP SENSOB MSIDE}Groond for CYP sensor signal.
15."BLU/BLKVTM (VTEC PRESSUREswtTcH)Oetscts VTEC pressure switch signal.Wrth engine at low enginespeed:0 VWth engineathigh engine speed: tatteryvoltase
16GRN
PSPSW (P/S OIL PRESSUREswtTcH)Detects PSP switch signal.At idle with steering wheel in straight aheadposition:0 VAt idle with stsering wheet at fult tock batteryvoltage'17WHT/REDALTF (ALTERNATOR FRSIGNAL)Detects ahernator FR signal.With fullyw6rmed up engine running:0 V- bat-teryvohage (depending on electricat toad)18BLUI/VHTVSS {VEHICLE SPEED SEN-SOR}Oetects VSS signal.Whh ignitjon switch ON {tt) and front wheetsrotating: cycles 0 V- 5 V23+14BLKlP+ {HO2S PUtr4P CELL +}Controls HO2S pump ce .With ignition switch ON (ll): abour 0.5 - 5.3 V
24.10REDrP-, vs- {Ho2s coMt oN)Reference voltage supply.With fullywarmed up engine et idle:about2.6-2.8 V25*roVS+ (VS CELL VOLTAGE)Detects VS cell voltage.With ignition switch ON t): abour 7 V
29LT GRN*'ATPNP (Ar'T GEAR POSI,TroN swrTcH)Deteds Ay'T g6srposhion switch signat.In E orE position: O Vln any other position: battery vottage
RED{roCLSW (CLUTCH SWITCH}Detects clutch switch signal,Wilh clutch pedal released: about 5 VWith clutch pedal deDressed: O V30PNK4TMBData communication with TCM:ECM controldata inputWith ignit;on switch ON (lt):putses

,'o
L
*:The E indicator light and the Maltunction Indicator Lamp (MlL) may come on simultaneously.*1: D16Y5 engine (CVT)"5: '96 D16Y5 engine, D16Y7 engine, D16Y8 engine (sedan).'97 D16Y5 engine, Dl6Y7 engine (coupe: KA, KC models, sedan: KA.
KC, KL (DX) models, hatchback: all models), D16Yg engjne (sedan: KA, KC models)*6: '96 D16Y8 engine (coupe),'97 Dl6Y7 engine (coupe: KL model, sedan: KL (LX) model),'97 D'16Y8 engine (coupe: all models,
sedan: KL model),'98-all models,'99-all models,'00-all models*12: Except A,,/T (D16Y7, D16Y8 enginei*13: A"/T (D16Y7, D16Y8 engine)!l*14:'97 model*16:'98 model" 17: '99 - 00 models
(cont'd)
1 1-99
DTC{MlL indication}Detoction lt€mProbable C.usePage
P0441*5 (92)
Evaporative Emission ControlSystem InsufficientPurge Flow
EVAP Purge Control Solenoid VaiveOpen or short in EVAP Purge Control
Solenoid Valve circuitEVAP Control CanisterVacuum linesECM/PCM
11-271
P0451'11 (91)FuelTank Pressure Sonsor CircuitRange/Parformance
. FuelTank Pressure Sensor' ECM/PCM11 274
P0452{6(9r )
Fuel Tank Pressure Sensor CircuitLow Input
Short in FuelTank Pressure Sensor circuatFuel Tank Pres$ure SensorECM/PCM
11-275
P0453*6 {91)
Fuel Tank Pressure Sensor Circuit
High Input
ODen in Fuel Tank Pressure Sensor circuit
Fuel Tank Pressure Sensor
ECM/PCM
11-219
P0500*1, (17)Vehicle SpeedSensor CircuitMalfunction
V€hicle Speed SensorVehicle Speed Sensor circuit
ECM
11-176
P0501*'3 l17l
Vehicle SpeedSensor CircuitRange/Performance
V€hicle Sp€ed SensorVehicle Speed Sensor circuitPCM
r 1- 176
P0505 (14)ldle Control Systemlvl a lfu n ctio n
. IAC valve. Throttle Body11-192
P0700*r3and some ofP0715P0720P0730 (70)*
P0740P0753P0758
AutomaticTransaxle
Section 14
P0700*1and (70)*
P0725
Automatic TransaxleSection 14
(13)Barometric PressureCircuitRange/Performance Problem
. ECM/PCM (Baro sensor)1 1-178
P1107 (13)BarometricPressure CircuitLow Input
. ECM/?CM (Baro s€nsor)11-178
P1108 (13)BarometricPressure CircuitHigh Input
. ECM/PCM lBaro sensor)1 1-178
P1121*'. *16. *'? \71Throttle Position Lower ThanExpected
. I r sensor11-138
P1122'14.*16.*n 17lThrottle Position Higher ThanExpected
. TP sensor11-'138
15)Manifold Absolute PressureLower Than Expected
. MAP sensor1 1'123
P1129*1r.*16.*"(5)Manifold Absolute PressureHigher Than Expected
. MAP sensor't1-123

DTC(MlL indicationlDetection ltemProbable CausePage
P1336(54iCrankshaft SpeedFluctuation SensorIntermittent Interruption
. CKF sensor11 183
P1337 (54)Crankshaft SpeedFluctuation SensorNo Signal
CKF sensorCKF sensor circuitECM,PCM
11-'183
P13s9 (8)Crankshaft Position/TopDead Center SensorDisconnected
' CKP/TDC sensor circuit11-187
P1361 (8)Top Dead CenterSensor IntermittentInterruptron
. tuL sensor
11-172
P1362 (8)Top Dead CenterSensor No SignalTDC sensorTDC sensor circuitECIV/PCM
11-172
P1381 {9)Cylinder Position SensorIntermittent Interruption
. CYP sensor11-172
P1382 (9)Cylinder Position SensorNo SignalCYP sensorCYP sensor circuitECM/PCM
11-112
P1456*5(90)
Evaporative Emission ControlSystem Leak Detected {FuelTankArea)
FuelfillcapVacuum connectionFu€ltankFuel tank pressure sensorEVAP bypass solenoid valveEVAP two way valveEVAP control canister vent shut valveEVAP control canisterEVAP purge control solenoid valve
11-283
P1457*6 (90)
Evaporative Emission ControlSystem Leak Detected (EVAP
Control Canister Area)
Vacuum connectionEVAP control canisterFuel tank pressure sensorEVAP bypass solenoid valveEVAP two way valveEVAP control canister vent shut valveFuel TankEVAP purge control solenoid valve
11-283
L
*6: '96 D16Y8 engine (coupe),'97 Dl6Y7 engine (coupe: KL model, sedan: KL (LXl model),'97 D16Y8 engine (coupe: all models,
sedan: KL model),'98-all models,'99-all models,'00-all models.
(cont'd)
1 1-1 01
I ta

3.
5.
6.
1.
Fuel Cut-off Control
. During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at
speeds over the following rpm:. D16Y5 engine (M/T):850 rpm. D]6Y5 engine (CVT), D'16Y8 engine (USA M/T): 920 rpm
. Dl6Y8 engine (USA A,/I), D16Y7 engine (USA A,/T);910 rpm
. D16Y8 engine (Canada M/T), D16Y7 engine (canada): 990 rpm
' D16Y8 engine (Canada M/T): 1,000 rpm
. 816A2 engine: 970 rpm
. Fuel cut-off action also takes place when engine speed exceeds 6,900 rpm (D16Y5, D16Y7 engine; D'16Y8 engine:
7,000 rpm. 816A2 engine: 8.100 rpm), regardless of the position of the throttle valve, to protect the engine from
over-rewing. With '99 Dl6Y7 engine (A,/T) and '99 D16Y8 engine (A./T), the PCM cuts the fuel at engine speeds over
5,000 rpm when the vehicle is not moving.
IVC Compressor Clutch Relay
When the ECM/PCM receives a demand for cooling from the air conditioning system, it delays the compressor from
being energized, and enriches the mixture to assure smooth transition to the A,/C mode
Evaporative Emission (EVAP) Purge Control Solenoid Valve*'
When the engine coolant temperature is above 154'F (68'C). the ECM/PCM controls the EVAP purge control solenoid
valve which controls vacuum to the EVAP purge control canister.
Evaporative Emission (EVAP) Purge Control Solenoid Valve*a
When the engine coolant temperature above 154"F (68"C), intake air temperature above 32"F (0'C) and vehicle speed
above 0 mile (0 km/h) or [Ay'C compressor clutch on and intake air temperature above 160"F (41'C)], the ECM/PCM
controls the EVAP purge control solenoid valve which controls vacuum to the EVAP purge control canister.
Exhaust Gas Recirculation (EGR) Control Solenoid Valve*?
When EGR is required for control of oxides of nitrogen (NOx) emissions. the ECM controls the EGR control solenoid
valve which supplies regulated vacuum to the EGR valve
Alternator Control
The system controls the voltage generated at the alternator in accordance with the electrical load and driving mode,
which reduces the engine load to improve the fuel economy.
ECM/PCM Fail-safe/Back-up Functions
1. Fail safe Function
When an abnormality occurs in a signal from a sensor, the ECM/PCM ignores that signal and assumes a pre-pro-
grammed value for that sensor that allows the engine to continue to run.
2. Back-uD Function
When an abnormality occurs in the ECM/PCM itself, the fuel injectors are controlled by a back-up circuit independent
of the system in order to permit minimal driving.
3. Self diagnosis Function lMalfunction Indicator Lamp (MlL)l
When an abnormality occurs in a signal from a sensor, the ECM/PCM supplies ground for the lvllL and stores the DTC
in erasable memory. When the ignition is initially turned on, the ECM/PCM supplies ground for the MIL for two sec-
onds to check the MIL bulb condition.
4. Two Trip Detection Method
To prevent false indications, the Two Trip Detection Method is used for the HO2S, fuel metering-related. idle control
system, ECT sensor, EGR system and EVAP control system self-diagnostic functions. When an abnormality occurs,
the ECM/PCM stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and
ON 0l) again, the ECM/PCM informs the driver by lighting the MlL. However, to ease troubleshooting, this function is
cancelled when you jump the service check connector. The MIL will then blink immediately when an abnormality
occurs,
5. Two (or Three) Driving Cycle Detection Method
A "Driving Cycle" consists ot starting the engine. beginning closed loop operation, and stopping the engine. lf misfir-
ing that increases emissions is detected during two consecutive driving cycles, or TWC deterioration is detected dur-
ing three consecutive driving cycles, the ECM/PCM turns the MIL on. However, to ease troubleshooting, this function
is cancelled when you jump the service check connector. The MIL will then blink immediately when an abnormality
occurs.
(cont'd)
1 1-1 05
.1.

Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1l
The scan tool indicates Diagnostic Trouble Code (DTC) P0133: A slow response problem in the Primary Heated
Oxygen Sensor {Primary H02S) (Sensor 1) circuit.
The scan tool indicates Diagnostic Trouble code (DTC) Pl163: A slow response problem in the Primary Heated
Oxygen Sensor (Primary HO2S) (Sensor 1)circuit
Description
By controlling the airlfuel ratio with a Primary Ho2S {Sensor 1) and a secondary HO2S {Sensor 2), the deterioration of the
primary HO2S (Sensor 1) can be evaluated by its feedback period. when the feedback period of the Ho2s exceeds a cer-
tain value during stable driving conditions, the sensor will be judged as deteriorated
when deterioration has been detected during two consecutive trips. the MIL comes on and DTC P0133 or P1163* will be stored'
NOTE: tf DTC P0131, P0132 and/or P0135 are stored at the same time as DTC P0133, troubleshoot those DTCS first' then
troubleshoot DTC P0133. lf DTC Pl 162, P1168 and/or P1169 are stored at the same time as DTC P1163, troubleshoot those
DTCS first, then recheck for DTC Pl163.
Possible Cause
o Primary HO2S (Sensor 'l) Deterioration
o Primary HO2S Heater (Sensor 1)Deterioration
. Exhaust system leakage
Troublsshooting Flowchart
tFol3al
I P1163
- The MIL has been reported on- DTC P0133 and/or Pl163* is
stored,
Problem Verilication:1. Do the ECM/PCM Reset Pro
cedure-2. Connect the scan tool
3. Start the engine. Hold the
engine at 3,000 rpm with no
load (in Park or neutral) until
the radiator fan comes on
4. Connect the SCS service con-
nector.5. Test-drive u nder Iollowing
conditions.- 55 mph (88 km/h) steadyspeed- A/f in D position {M/T in
5th gear)
Until readiness code comes
lntermittent failure, 3Y3tem i3 OK
at thi3 time. Ch.ck lol Poor con-
ncctions or loosc wiros at C123
{C145)! lPrimary HO2S, Sensor 1l
and ECM/PCM.
Replace th6 Prim.ry HO2S (Sen'
sor 11.
*: P'l163 (D16Y5 engine with M/T)
11-145

PGM-FI System
l:in1.".fy Heated Oxygen Sensor (primary HO2SI (sensor 1l(D16Y5 engine with M/D (cont'd)
The scan toor indicates Diagnosti" -Tl:y|* code (DTC) pl164: A range/performance probrem in the primaryHeated Oxygen Sensor (primary HO2S) (Sensor 1)circuit.
The scan tool indicates Diagnostic Trouble Code (DTC) p1165: AHeated Oxygen Sensor (primary HO2S) (sensor 1) circuit.
range/performance problem the pnmarv
The MIL has beon reponed on.DTC P1164 is stored.
Problem Verilication:1. Do the ECM Beset Procedure.2. Start the engine. Hold theengine at 3,000 rpm with noload (transmission in neutral)untilthe radiatorfan comes on.3. Connect the SCS service con-nector.4. Test-drive in 4th gear. Startingat 1,600 rpm, accelerate usingwide open throttle for at least 5seconds. Then decelerate tor atleast 5 seconds with the throttle completely closed.
Intgrmittent failure, syrtem b OKat this time. Check tor Door con-noctions or loose wires at C1a5(Primary HO2S. Senso.

andECM.
ls DTC Pl164 indicatedT
- The MIL has been reoorted on.- DTC P1165 is stored.
Intermittent l.iluro, system b OKat lhis time. Ch€ck tor poor con-noctions or loose wir6 at Ci45(Prioary HO2S, Sen3or 1l .ndECM.
ls DTC P1165 indicated?
Replace the P.imary HO2S (S6n-sor 11.
Problem Vo.ification:1. Do the ECM Reset Procedlre.2. Start the engine. Hotd theengine at 3,000 rpm with noload (transmission in neutral)until the radiator fan comes
3. Connect the SCS service con,nector.4. Test-drive u nder followingconditions.- 55 mph steady speedTransmission in 5th gearUntil readiness code comes
1 1-150

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

I
Misfire Detected in One Cylinder
P0301 | The scan tool indicates Diagnostic Trouble Code (DTC) P0301: Cylinder 1 misfire detected.
[F03O2l 16"""untool indicates Diagnostic Trouble code (DTc) P0302: Cylinder2 misfire detected.
[FO3Ofl 16" ".un toot indicates Diagnostic Troubte Code (DTC) P0303; Cylinder 3 misfire detected.
I P0304 I ths..rr tool indicates Diagnostic Trouble Code (DTC) PO3O4: Cylinder 4 misfire detected.
D€scription
lMisfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensor
which 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 DTC
PO3O1, P0302, PO3O3 or P0304 will be stored. Then, after the misfire has ceased, the MIL will come on.
lf misfiring that increases emissions is detected during two consecutive driving cyclss, the MIL will come on, and DTC
P0301, P0302, P0303 or 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, then
recheck for the misfire DTC.
PO106*1, P0107, P0108. P1128*3'*5, P1129*3'*5: MAP sensor
P0131, P0132: HO2S
P0171, P0172iFuel suppiy system
P0335, P0336: CKF sensor
P0401. P1491, P1498: EGR system
P0441: EVAP system Insufficient purge flow*6
Pl359. P1361. Pl362: TDC sensor
P1381. Pl382: CYP sensor*o: '96 models*6: '96 D16Y5 engine,'96 D16Y/ engine,'96 D16Y8 engine {sedan),'97 D16Y5 engine,'97 D16\4, engine (coupe: KA,
KC models, sedan KA. KC, KL (DX) models, hatchback:all models),'97 D16Y8 engine (sedan: KA, KC models)
Possible Cause
. Fuel injector clogging, fuel leakage, air leakage
. Fuel injector circuit open or shorted
. Spark plug carbon deposits, fouling, malfunction
. lgnition wires open. leaking
. Distributor malfunction
. ComDression low
. Valve clearance out of spec
. VTEC system malfunction (D16Y5, D16Y8. 81642 engine)
. HO2S
. HO2S circuit
(cont'd)
11-167
r'a