Iac valve HONDA CIVIC 1996 6.G Owner's Manual

Troubleshooting
DTClMlL indicationlDatection hsmProbablo CausePage
P0137(63)Secondary Heated Oxygen SensorCircuit Low Voltage(Sensor 2)
Short in Secondary HO2S lSensor 2) circuitSecondary H02S {Sensor 2)ECM/PCI\41 1-153
P0r38 {63)Secondary Heated Oxygen SensorCircuit High Voltage(Sensor 2)
Open in Secondary HO2S (Sensor 2) circuitSecondary HO2S (Sensor 2)EC[I/PCM11-154
P0'139 (63)Secondary Heated Orygen SensorSlow Response(Sensor 2)
Secondary H02S lSensor 2)1l-156
P0141 (65)
Secondary Heated Oxygen SensorHeaterCircuit Malfunction(Sensor 2)
. Open or short in Secondary HO2S (Sensor2) heater circuit. ECM/PCM11-157
P0171 (45)
System Too LeanFuel supply systemPrimary HO2S (Sensor 1)MAP sensorContaminated fuelValve clearanceExhaust leakage
11,164
P0172 (45)
System Too RichFuel supply systemPrimary HO2S (sensor l)MAP sensorContaminated fuelValve clearance
11-164
P0300*16' }l?
andsome ofPo3o1 /r'' \P0302 l72lP0303 l73lP0304 \7 4l
Random Misfirelgnition systemFuel supply systemMAP sensorEGR systemIAC valveContaminated fuelLack of fuel
r1-r66
P0301P0302P0303P0304
/rt\172ll73l\7 4l
- Cylinder 1- Cylinder 2- Cylinder 3- Cylinder 4Misfire Detected
Fuel InjectorFuel Injector circuitlgnition systemLow compressionValve clearance
11 167
P0325*3 (23)Knock Sensor (KS) CircuitMalfunctionOpen or short in Knock Sensor (KS) circuitKnock Sensor {KS)ECM/FCtvl11-170
P0335(4)Crankshaft PositionSensor CircuitMalfunction
Crankshaft Position SensorCrankshaft Position Sensor circuitECM/PCM11-172
P0336(4)Crankshaft PositionSensorRange/Performance
. Crankshaft Position Sensor. Timing belt skipped teeth11-172
P040'r*r (80)Exhaust GasRecirculationInsufficient Flow Detected
' EGR valve. EGR line
P0420(67)Catalyst SystemEfficiency BelowThreshold
. Th.ee Way Catalytic converter. Secondary HO2S11 253
Diagnostic Trouble Code (DTCI Chat (cont'dl
*3: D16Y5 engine (CVT), D16Y8 engine and B1642 engine*4: D'16Y5 engine*16: '98 model+17: '99 - 00 models
,Jla
1 1-98

,'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

Troubleshooting
Diagnostic Trouble Code (DTGI Chart (cont'dl
*7: D16YS engine (M/T)*8: D16Y5, D'16Y8 engine*9: USA model*14r'97 model*15r '96 model
DTC(MlL indicationlDetection lt6mProbablc CausePage
P1162+1 (48)Primary Heated Oxygen Sensor(Sensor 1) CircuitMalfunction
Open or short in Primarv HO2S (Sensor 1Primary H02S (Sensor 1)1 1- 146
P]163' (61)Primary Heated Oxygen Sensor(Sensor '1) CircuitSlow Response
. Primary HO2S (Sensor 1)
11-145
Pl164*r (61)Primary Heated Oxygen Sensor(Sensor l) Cjrcuit Range/Performance Problem
. Primary HO2S (Sensor 1)
1 1- 150
P1165*? (61)Primary Heated Oxygen Sensor(Sensor 1) Circuit Range/Performance Problem
. Primary HO2S (Sensor 1)
11-150
P1166' (41i
Primary Heated Oxygen Sensor(Sensor '1) Heater System ElectricalProblem
Open or short in Primary HO2S (Sensor 1)heater circuitPrimary HO2S (Sensor 1)ECM/PCM
1 1-'161
P1167*' (41)Primary Heated Oxygen SensorlSensor 1) Heater SystemMalfunction
Open in Primary HO2S (Sensor 1) VS+ circuitPrimary HO2S (Sensor 1) HeaterPrimarv HO2S {Sensor 1)1 1- 163
P1168*' (48)Primary Heated Oxygen Sensor(Sensor 1) LABEL Low Input
. Short in Primary HO2S (Sensor 1) LABELcircuit11-151
Pl169*? (48)
Primary Heated Oxygen Sensor(Sensor 1)IABEL High Input. Open in Primary HO2S (Sensor 1)IABELcircuit. Short in ground circuit11.152
P1259*3(221
WEC System MalfunctionWEC Solenoid ValveOpen or short in WEC SolenoidValve circu itVTEC Pressure SwitchOpen or short in VTEC Pressure SwitchcircuitECM,FCM
Section 6
P1297*s (20)Electrical LoadDetector CircuitLow Input
Electrical Load DetectorElectrical Load Detector circuitECM/PCM11-179
Pr298+' l20l
Electrical LoadDetector CircuitHigh Input
Electrical Load DetectorElectrical Load Detector circuitECM/PCM1 1-181
anosome ofP0301P0302P0303P0304
l71ll72ll73ll7 4l
Bandom Misfirelgnition systemFuel supply systemMAP sensorEGR systemIAC valveContaminated fuelLack ol fuel
11-166
1 1-100

Troubleshooting
Diagnostic Trouble Code (DTCI Ghart (cont'd)
DTClMlL indicationlDetegtion homProbablo CsussPage
P1491*! \12J
EGR ValveLift InsufficientDetected
EGR valve (with lift sensor)EGR valve lift sensor circuitEGR control solenoid valve (A,/I)
EGR control solenoid valve circuitEGR lineEGR valve circuit (M/T)
ECM
't1-256
P1498*. 112)
EGR ValveLift SensorHigh Voltage
EGR valve (with lift sensor)EGR valve lift sensor circuitECM11-265
Pl508*10 (14)
ldle Air Control ValveCircuit FailureIAC valveIAC valve circuitECM
'11-194
{14)
ldle Air Control ValveCircuit FailureOpen or short in IAC valve circuitIAC valveECM/PCM1l-198
P1607 1-)
Engine ControlModule/Powertrain Control lvlodulelnternalCircuit Failure A
. ECM/PCM
11-188
P1655*1 (30)TMA,/TMB Signal Line FailureODen or sho.t in TMA,/TMB circuit11-189
P1705P1706P 1753P1758P1768P1785P1790P1791P1793 (70)*
P1870P1873P1879P1885P1886P1888P1890P1891
Automatic Transaxle
Section 14
*: The E indicator light and the Malfunction Indicator Lamp {MlL) may come on simultaneously.*4: D16Y5 engine (M/T)+10: Except A/T and Dl6Y7 engine*11: A,/T and D16Y7 engine*18: D16Y5 engine (CW) (except '99 - 00 models)
11-102

PGM-FI System
System Description
CKP/TDC/CYP Sensor
MAP Sensor
IAT SensorTP SensorEGR Valve Lift Sensor*'Primary H02SSecondary HO2SVSSBARO SensorELD*'KS€Starter SignalALT FR SignalAir Conditioning SignalA/T Gear Position SignalBattery Voltage {lGN.1}Erake Switch SignalPSP Switch SignalFuel Tank Pressure Sensor*iVTEC Pressure Switch*5Clutch Switch Signal*6Countershaft Speed SensornBMainshaft Speed Sensorrs
-\
----t /
F;ilrr j"-----fi-tri-'r.;l
Fb"t."'i" d" c;;il
F,h"'c;;tr*".io";-l
@."r.l"sc;;ll
EaM/PcM B""k-p F"""till
r\
-:/
Fuel IniectorsPGM-Fl Main Belay {Fuel Pump)MILIAC Valve!y'C Compressor Clutch RelayRadiator Fan Relay*,Condenser Fan RelayALT*'lcMEVAP Purge Control Solenoid
Primary HO2S HeaterSecondary H02S HeaterEGR Control Solenoid Valve*rEGR valve*6EVAP Bypass Solenoid Valve*'EVAP Control Canister Vent Shut
VTEC Solenoid Valve*5DLCLock-up Control Solenoid Valve*aShift Control Solenoid Valve*3Linear Solenoid Valve*3
*1: Dl6Y5 engine*2: USA model*3: CW (D16Y5 ensine), D16Y8 engine and 81642 ensine*4: '96 D16Y8 engine lcoupe),'97 Dl6Y7 engine (coupe: KL model, sedan: KL (LX) model),'97 D16Y8 engine {coupe: all models, sedan: KLmodel),'98-all models,'99'all models,'00-all models+5: D16Y5, D16Y8,816A2 engine*6: M/T (D16Y5 enginei*7: CVT 1D'l6Y5 engine)+8: A/T (D16Y7, D16Y8 engine)*9: '96 D16Y5 engine,'96 D16Y7 engine,'96 Dl6Y8 engine (sedan),'97 D16Y5 engine,'97 Dl6Y7 engine (coupe: KA, KC models, sedan:KA, KC, KL (LX) models, hatchback: all models),'97 D16Y8 engine (sedan: KA, KC modelsi
PGM-FI Sy3lem
The PGM-Fl system on this model is a sequential multipon fuel injection system.
Fuel iniector Timing and Duration
The ECM/PCM contains memories for the basic discharge durations at various engine speeds and manifold air flow rates.
The basic discharge duration, after being read out from the memory. is further modified by signals sent from various sen-
sors to obtain the final discharge duration.
ldle Air Control
ldle Air Control Valve llAC Valve)
When the engine is cold. the A,/C compressor is on, the transmission is in gear, the brake pedal is depressed, the P/S load
is high, or the alternator is charging, the ECM/PCM controls current to the IAC Valve to maintain the correct idle speed.
lgnition Timing Control
. The ECM/PCM contains memories for basic ignition timing at various engine speeds and manifold air flow rates.
lgnition timing is also adjusted for engine coolant temperature.
. Aknockcontrol system was adopted which sets the ideal ignition timing for the octane rating ofthegasoline used.*3
Othgr Control Funqtions
1. Starting Control
When the engine is started, the ECM/PCM provides a rich mixture by increasing fuel injector duration.
2. Fuel Pump Control
. When the ignition switch is initially turned on, the ECM/PCM supplies ground to the PGM-Fl main relay that sup-plies current to the fuel pump for two seconds to pressurize the fuel system.. When the engine is running, the ECI\4PCM supplies ground to the PGM-FI majn relay that supplies current to the fuel
oumo.
. When the engine is not running and the ignition is on, the ECM/PCM cuts ground to the PGM-FI main relay which
cuts current to the fuel pump.
11-104
INPUTS
ENGINE CONTROL MODULE (ECMY
POWERTRAIN CONTROL MODULE (PCM) OUTPUTS

PGM-FI System
(From page 11-109)
Replace the sensor that causedthe light to go out.Does the N4lL go OFF?
Check fo. a short in the wi.os(VCC lines):':. Turn the ignition switch OFF.2. Disco n n ect the ECM/PCMconnector D (16P).
3. Check for continuity betweenbody ground and ECM/PCMconnector terminals D4 andD10 individually.
Ropair short to body groundin the wire betweon ECM/PCM {O4) and MAP s6n3or.Repair short to body groundin the wire between ECM/PCM lD10l, the TP sensor, theEGR valve lift sensor {D16Y5engine) and/or the Fuel tankpressure sensor {'96 Dl6Ygengine lcoupe),'97 D16Y7engine (coupe: KL model,sedan: KL (LXl model), '97
D16Y8 engine (coupe: allmodels, sedan: KL model. €8-allmodelsl.
ls there continuity?
Check tor rn open in the wires(lGP lines):1. Disconnect the fuel injectorsand IAC valve connectors,2. Turn the ignition switch ON (ll).3. Meas u re voltage betweenbody ground and ECM/PCMconnector terminals A11 and424 indivjdually.- Repair open in the wirels)between ECM/PCM (A11,A24land PGM-Fl main relay.- Check for poor connectionsor loose wiras at the PGM-FImain relay,- Test the PGM-FI mdin relavlsee pag6 11-237).
ls there battery vohage?
Check for an open in the wires(LG line3):1. Reconnect all sensor connectors.2. Reconnect the ECM/PCM con-nector D (16P).
3. Turn the ignition switch ON (ll).4. Measure vo ltage betweenbody ground and ECM/PCMconnector terminals Ag andA22 individually.
Repair open in the wirolglb€twe€n ECM/PCM {A9, A22} andG101 that had more than 1.0 V.
ls there less than 1.0 V?
Substitute 6 known-good ECM/PCM and r€check. lf symptom/indication 9o€s away, replacethe original ECM/PCM.
Engine Control Module/Powertrain Control Module (ECM/pCMl
('96 - 98 Models, '99 - 00 D16Y5 engine with M/Tl (cont,dl
ECM/PCM CONNECTOR D {16P}
Wire side of female terminals
ECM/PCM CONNECTOR A (32P}
Wire side of female terminals
11-110
LG1
VCCl {YEL/RED}
IGP 1{YEL/BLKI
2I11
1213l5t6Itt8t9202321
25272a2930
IGP 2(YEL/BLKIv) (l
{8RN/BLK)
I258tol1'12tt11t5l617t8t920232a
2A2330
LG2{8RN/8LK}

PGM-FI System
(From page'11-111)
Check loi an open in the wires(lGP linesl:1. Disconnect the lueliniector andIAC valve connectors.2. Turn the ignition switch ON (ll).
3, Measu re voltage betweenbody ground and ECM/PCMconnector terminals 81 andBg individually.
- Repair open in the wiro(3)between ECM/PCM lBl, B9land PGM-Fl main relay.- Check tor poor connectionsor loose wires al the PGM-FImain relav.- Test tho PGM-FI main rehy(3.e page 11-237).
ls there battery voltage?
Check tor an open in the wires(PG, LG lines):1. Reconnect the fuel iniectorand IAC valve connectors.2. Measure voltage betweenbody ground and ECM/PCMconnector terminals 82, 810,820 and 822 individually.
Repair open in the wirels)between ECM/PCM and G 101llocated ai the l6ft side of thointaks m.nifoldl thrt h.d morethan 1.0 V.
ls there lessthan 1.0 V?
Check for a short in the wires
{VCCI, VCC2 lin6s}:Measure voltage between bodyground and ECM/PCM connectorterminals C19 and C28 individually.Check toa a 3hort in s 3ensor:While measuring voltagebetween body ground and ECM/PC[/t connector terminals C19and C28 individually, disconnectthe 3P connector of each sensorone at time:. MAP sensor. TP sensor. EGR valve. Fueltank pressure sensor
ls there approx.5 V?
Reoair short in lhe wire betwe.enMAP 3ansor, TP sensor, EGRvalve, Fuel tank pres3ure 3ensorand ECM/PCM {Cl9, C28).
ls there approx. 5 V?
Substiiute a known-good ECM/PCM and racheck. ll symptom/indicetion goes eway, replaceth6 original ECM/PCM.Replace tho sansor that had.pprox. 5 V.
Engine Control Module/Powertrain
('99 - 00 Model except Dl6Y5 (M/Tl
Module (ECM/PCM)
(cont'd)
Control
engine)
ECM/PCM CONNECTOR B {25P)
LG1 (BRN/BLKI
Wire side of female terminals
ECM/PCM CONNECTOR C (31P)
female terminalsvcc2IYEL/BLUIvccl{YEL/RED)
Wire side of female terminals
11-112

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

ldle Control System
System Description
The idle speed ot the engine is controlled by the ldle Air Control (lAC) Valve.The valve changes the amount of air bypassing into the intake manifold in response to electric current controlled bv theECM/PCM. When the IAC Valve is activated, the valve opens lo maintain the proper idle speed.
D16Y5, D16Y8, Br6A2 engine (M/T):
(ROTARYItac vat-vEEI{GINEcooLAI{T
VARIOUSsEI{SORS
VARIOUSSENSORS
INTAKE MANIFOTDDl6Ys {CVTl, D16Y8 engine lA/T):
D16Y7 engine:
{ROTABY)
;iy--, - --- INTAKEMANIFOLD
11-190

1.After the engine starts, the lAc valve opens for a certain time. The amount of air is increased to raise the idle speed
about 150 - 300 rpm.
When the coolant temperature is tow, the IAC valve is opened to obtain the proper fast idle speed. The amount of
bypassed air is thus controlled in relation to the engine coolant temperature'
IOLE SPEED
lrpml
176
80
ENGI ECOOLANI TEMPERATURE
t" Fl
toc)
ll
't.Whentheid|espeedisoutofspeciiicationandthescantoo|doesnotindicateDiagnosticTroub|ecode(DTc)P0505
or P1508. check the following items:
. Adiust the idle speed {see page 11-220}
. Starter switch signal (see page 11-202)
. Air conditioning signal (see page l1-204)
. ALT FR signal (see Page 11-2081
' Brake switch signal (see page 11-210)
. PSP switch signal (excapt Canada model) (see page 11-212)
. A,/T gear position signal {see section 14, Dl6Y5 engine (CVT):
page 11-216). Clutch switch signal (D16Y5 engine with M/T) (see page 11-218)
. Hoses and connections
' IAC valve and its mounting O-rings
lf the above items are normal, substitute a known-good IAC valve and readjust the idle speed (see page 11-220)
|ftheid|espeedsti||cannotbeadjustedtospecification(andthescantoo|doesnotindicateDTcP0505orP]50S)
after IAC valve replacement. substitute a known-good ECM/PCM and recheck. lf symptom goes away, replace the
original ECM/PCM.