Fuel pressure HONDA CR-V 2000 RD1-RD3 / 1.G User Guide

'99 - 00 models:
To EVAP THREEWAY VALVETo EVAPTWO WAY VALVE
EVAPPURGECONTROLSOLENOIDVALVE
FUELPRESSUREREGULATOR
FRONT OFVEHICLE
(cont'd)
1 1-13
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System Description
Vacuum Connections (cont'dl
'99 - q) models:
ENGINECOOLANT
t
o
o
o@
o@@@@@@@@@(t
PRIMARY HEATED OXYGEN SENSOR IPRIMARY HO2S,SENSOR 1lSECONDARY HEATED OXYGEN SENSOR {SECONDARYHO2S. SENSOR 2lMANIFOLD ABSOLUTE PRESSURE (MAPI SENSORENGINE COOLANT TEMPERATURE IECN SENSORINTAKE AIR TEMPERATURE IIATI SENSORCRANKSHAFT SPEED FLUCTUATION {CKF) SENSORKNOCK SENSOR (KS}
IDLE AIR CONTROL IIACI VALVEFAST IDLE THERMO VALVE {A/T}THROTTLE BODY (TB}
FUEL INJECTORFUEL PULSATION DAMPERFUEL FILTERFUEL PRESSURE REGULATORFUEL PUMPFUEL TANKFUEL TANK EVAPORATIVE EMISSION (EVAPI VALVE
AIR CLEANERRESONATORPOSITIVE CRANKCASE VENTILATION (PCV} VALVETHREE WAY CATALYTIC CONVERTER ITWCIEVAPORATIVE EMISSION {EVAPI CONTROL CANISTEREVAPORATIVE EMISSION IEVAPI PURGE CONTROLSOLENOID VALVEEVAPORATIVE EMISSION {EVAPI CONTROL CANISTEFVENT SHUT VALVEEVAPORATIVE EMISSION IEVAPI TWO WAY VALVEEVAPONANVE EMISSION {EVAPI AYPASS SOLENOIDVALVEFUEL TANK PRESSURE SENSOBEVAPORATIVE EMISSION IEVAPI THREE WAY VALVEPURGE JOINT
@@@@@@
@
@@
@@@
11-14
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ECM/PCM Data
By connecting the OBD ll scan tool or the Honda PGM Tester to the 16P data link connector (OLC), various data can be
retrieved from the ECM/PCM. The items listed in the table below conform to the SAE recommended practice
The Honda PGM Tester also reads data beyond that recommended by SAE.
understanding this data will help to find the causes of intermittent failures or engine problems.
NOTE:
The ',operating values" given below are approximate values and may be different depending on the environment and
the individual vehicle.
Unless noted otherwise. "at idle speed" means idling with the engine completely warmed up, transmission in position
Park or neutral and the A,./C and all accessories turned otf.
DataDesc.iptionOp€rating ValuoFreeze Data
Diagnostic
Trouble Code
(DTC)
lf the ECM/PCM detects a problem, it will store it as a
code consisting of one letter and tour numbers
Depending on the problem, an SAE-defined code (Poxxx)
or a Honda-defined code (P'lxxx) will be output to the
tester.
lf no problem is detected,
there is no output.
YES
Engine SpeedThe ECN4/PCN4 computes engine speed from the signals
sent from the Crankshaft Position sensor.
This data is used for determining the time and amount of
fuel iniection.
Nearly the same as
tachometer indication
At idle speed:'97 - 98 models:
750 t 50 rpm'99 - 00 models:
730 f 50 rpm
YES
Vehicle SpeedThe ECM/PCM converts pulse signals from the Vehicle
Speed Sensor (VSSI into speed data.
Nearly the same as
speedometer indicationYES
Manifold
Absolute
Pressure (MAP)
The absolute pressure caused in the intake manifold by
engine load and speed.
With engin6 stopped:
Nearly the same as atmo-
spheric pressure
At idle speed:
2a - 41 kPa {210 - 310
mmHg, 8.3 - 12.2 inHg)
YES
Engine Coolant
Temperature
{ECT)
The ECT sensor converts coolant temperature into volt-
age and signals the ECM/PCM. The sensor is a thermistor
whose internal resistance changes with coolant tempera-
ture. The ECM/PCM uses the voltage signals from the
ECT sensor to determine the amount of injected fuel
With cold engine:
Same as ambient temPer-
ature and IAT
With engine warmed uP:
approx. 163 - 2'12'F
(73 - 100"c)
YES
Heated Oxygen
Sensor (HO25)
(Primary,
Sensor 1)
(Secondary
Sensor 2)
The Heated Oxygen Sensor detects the oxygen content in
the exhaust gas and sends voltage signals to the
ECMiPCM. Based on these signals, the ECM/PCM controls
the airlfuel ratio. When the oxygen content is high (that is.
when the ratio is leaner than the stoichiometric ratio), the
voltage signal is lower.
When the orygen content is low (that is, when the ratio
is richer than the stoichiometric ratio), the voltage signal
is higher.
0.0 - 1.25 V
At idle speed:
about 0.1 - 0.9
NO
(cont'd)
1 1-65
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Engine/Powertrain Control Module Terminal Arrangement - 38 - 00 Models
ECM/PCM CONNECTOR A (32P}
,/./5aIsca
,/ l,/t5ItsTs
n2ls!uCI
Wire side ot female terminalsECM/FCM CONNECTOR A {32P)NOTE: Standard baftery voltage is '12 V.
D93criptionSignal
3BLU2WBS {EVAP BYPASSSOLENOID VALVE)Drives EVAP bvoass solonoid valve.With ignirion switch ON {ll)r battery voltage
LT GRNMHTVSV {EVAP CONTROL CANISTEB VENT SHUT VALVE)D.ives EVAP controlcanisler vent shutWith ig^ition switch ON (ll): battery voltage
5',BLUCRS (CRUISE CONTROL SIG'NAL)Shift Oown signalinputfrcm cruise conWhen cruise control is used: pulses
6RED/YEL
PCS (EVAP PURGE CONTROLSOLENOID VALVE)Drives EVAP purge controlsolonoid valve.With engins running, engine coolant, below 154'F(68'C)r battery voltageWith engine running, engine coolant, above 154"F{6a'C}r duty conl.olled
8ELIOWHTSO2SHTC (SECONDARVHEATED OXYGEN SENSORHEATER CONTROL)
Drives sacondary heated oxygen sensorWith ignition switch ON (ll): banery voltageWith fully warmed up engine running: duty
10BRNSCS (SERVICE CHECX SIGNAL)Detects seNics check conneclor signal(he signalcausing a DTC indicatjon)with rhe lerminal connected:0 vWith the rerminaldisconnectedrabout 5 v or
l4'rGRN/8LKD4IND (D4INDICATOR)+3DIND (D INDICATORTIDrives D4*3. Dr'indicaior light.W,rh 04' , O" indrcator light turned O batter,
With D4*3, D*. indicator light turned OFFr0 V
16GRNI/ELFLR (FUEL PUMP RELAY)Drivss fusl pump relay.0 V for iwo seconds after ru'nin9 ign'lion swilchON lll), then banery voltage
17AL|(/REDACC (I/C CLUTCH RELAY}Drives l,/C clurch rclay.With compressor ONr0 VWith compressor OFF: battery voltage
18GRN/ORNMIL (MALFUNCTION INDICA.TOR LIGHT)Driv€s MlL.With MlLturned ON:0 VWith MIL turned OFF: battery voltage
19BLUNEP (ENGINE SPEED PULSE)Outputs engine spsed pulse.With sngine runnin9: pulses
20GRNFANC {RADIATOR FAN CONTROL)Drives r6diator fan rslay.With radaator fan running:0 VWith radaatorfan stopped: battery vollage
218LU/t/ELK-LINESends and receiv€s scan toolsignal.With ignition switch ON (ll): p'rlses
23WHT/REDSHO2S (SECONDARY HEATEDOXYGEN SENSOR. SENSOR 2iDetects secondary h€at€d oxygen sensorWith throttle fully opened from idle wilh fullywalmed up engine: above 0.6 Vwith rhrottle quickly closed: below 0-4 V
21BLU/WHTSTS (STARTER SWITCH SIG,NAL}Dotocts srarter switch signal.Whh staner switch ON (lll): batlery voltageWith srarter switch OFF: 0 V
26GBNPSPSW {P/S PsESSUFESWITCH SIGNAL)Detecrs PSP switch signal.At idle with steeing wh€el in stBighl ahead position: 0 VAt idls with nee ng wheel al full lockr banory voltage
2fBLU/BEOACS (Ir'C SWTCH SIGNAL}D€tects ly'C switch signal.With Ay'C switch ON:0 VWith l/C swil€h OFF: about 5 V
2A'\WHT/NEDSLU {INTERLOCK CONTROLUNIT)Orives interlock control unil.With ignilion switch ON (ll)and brake pedaldepressed: battery vohage
29LT GRNPTANK (FUEL TANK PRES'SURE SENSOR)Detocts fueltank pressure sensor signal.With agnition switch ON (ll) and fuel fill capopensd; about 2.5 v
GBN/FEDEL (ELD}Detects ELD signal.Wirh paaing rightstumed on at idle:about 2.5 - 3.5 VWith low beam headlights tumed on at idle:about 1.5-2.5V
GRN/WHTBKSW (BRAKE SWTTCH)Dst€cts brake switch signal.Wirh brake pedal released:0 VWith brake pedal depressed: battery vollage
13: '98 modsl
15: USA(cont'd)
11-71
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Troubleshooting
Engine/Powertrain Control Module Terminal Arrangement - '98 - 00 Models
(cont'd)
ECM/PCM CONNECTOR B {25PI
Wire side of female terminalsECM/PCM CONNECTOR B I25PI
*2t MlT*3: '98 model"4: '99 - 00 models
NOTE: Standard baftery voltage is l2
Ierminalnumb€tWire colorTerminsl nameDescriptionSignal
1YEUBLKIGPl (POWER SOURCE)Power source for the ECM/PClvlcontrol circuit.withagewith
ignition switch ON (ll): battery volt-
ignition switch OFF:0 V
BLKPG1 (POWER GROUND}Ground for the ECM/PClvl controlcircuit.Less than 1.0 V at all times
REDlNJ2 (No. 2 FUEL INJEC-roR)Drives No. 2 Iuel injector.With engine running: duty controlled
BLUlNJ3 1No. 3 FUEL INJEC-TOR)Drives No. 3Iuel jnjector.
YELlNJ4 {No.4 FUEL INJEC-TOR)Drives No. 4 fuel injector.
8*1WHTLS- (A"/T CLUTCH PRES.SURE CONTROL SOLE,NOID VALVE _ SIDE)
A,/T clutch pressure controlsolenoid valve power supplynegative terminal.
With ignition switch ON (ll): dutycontrolled
9YEUBLKIGP2 IPOWER SOURCE)Power source for the ECN,I/PCMcontrol circuit.With ignition switch ON (lll: bafteryvoltageWith ignition switch OFF:0 V
10BLKPG2 (POWER GROUND}Ground for the ECM/PCM controlcrrcurt.Less than '1.0 V at all times
' BRNlNJl (No. 1 FUEL INJECTOR)Drives No. l tuel injector.With engine running: duty controlled
YEUGRNrcM {rGNrTroN coN-TROL MODULE)Sends ignition pulse.With ignition switch ON (ll): batteryvoltageWith engine running: pulses
17*1REDLS+ (A,,IT CLUTCH PRESSURE CONTROL SOLE-NOID VALVE + SIDE)
A,/T clutch pressure controlsolenoid valve power supplypositive terminal
With ignition switch ON (ll): dutycontrolled
19*.PNK
ODIND (OVER-DRIVE
OFF INDICATOR}Drives OVER-DRIVE OFFindicator light.With OVER-DRIVE OFF indicator lightturned ON: 0 VWith OVER-DRIVE OFF indicator lightturned OFF: battery voltage
20BRN/BLKLG1 (LOGIC GROUND)Ground for the ECM/PCM controlcircuit.Less than 1.0 V at all times
WHT/BLUVBU (VOLTAGE BACKUP)Power source for the ECM/PCMcontrol circuit.Power source forthe DTC memory.
Battery voltage at all times
22BRN/BLKLG2 (LOGIC GROUND)Ground for the ECN4/PCM controlctrcutt,Less than 1.0 V at all times
23BLVBLUIACV {IDLE AIR CON.TROL VALVE)Drives IAC valve.With engine running: duty controlled
11-72
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Diagnostic Trouble Code (DTCI Chart
*: These DTCS will be indicated by the blinking of the Malfunction Indicator Lamp (MlL) with the SCS service connector
connected.**: The E (E)*u indicator tight and the Malfunction Indicator Lamp (MlL) may come on simultaneously.*1' AIT *3 '97 model +5; '99 - 00 models*2: MlT *4:'98 model
{cont'd)
11-75
DTC(MlL indication*lDetection ltemProbable CausePago
P0107 (3)Manifold Absolute
Pressu.e CircuitLow Input
Open or short in MAP sensor circuit
MAP sensor
ECMiPCM
't 'l-90
P0108 {3)
Manifold AbsolutePressure Circuit
High Input
Open in MAP sensor circuitMAP sensor
ECM/PCM
11-92
P01 1 1*3 (10)Intake Air
Temperature Circuit
Range/Performance Problem
. IAT sensor
11-95
P0112 (10)lntake Air
Temperature CircuitLow Input
Short in IAT sensor circuit
IAT sensorECM/PCM1 1-96
P0113 (10)lntake Air
Temperature Circuit
High lnput
Open in IAT sensor circuit
IAT sensor
ECM/PCM
'I 1-97
P0116 (86)Engine CoolantTemperature CircuitRange/Performance Problem
ECT sensor
Cooling system1 1-99
P0117 (6)Engine Coolant
Temperature Circuit
Low Input
Short in ECT sensor circuit
ECT sensor
ECM/PCM
1 1-100
P0118 (6)Engine Coolant
Temperature CircuitHigh Input
Open in ECT sensor circujt
ECT sensor
ECM/PCM
11-101
P0122 \11
Throttle Position
Circuit
Low Input
Open or short in TP sensor circuitTP sensor
ECM/PCM
11-103
P0123 l7l
Throftle Position
Circuit
High Input
Open in TP sensor circuit
TP sensor
ECM/PCM11-107
P0131 (1)
Primary Heated Oxygen Sensor
Circuit Low Voltage(Sensor 1)
Short in Primary HO2S {Sensor 1)
circuit
Primary HO2S (Sensor 1)
Fuel supply system
ECM/PCM
1 1-1 10
P0132 (1)Primary Heated Orygen SensorCircuit High Voltage(Sensor 1)
Open in Primary HO2S (Sensor 1) circuitPrimary HO25 (Sensor 1)ECM/PCM
'11113
P0133 (61)Primary Heated Oxygen Sensor
Slow Response(Sensor 1)
. Primary HO2S (Sensor 1). Exhaust system11'I 16
P0135 (41)
Primary Heated Oxygen SensorHeater
Circuit Malfunction
{Sensor 1)
. Open or short in Primary HO2S (Sensor'l) heater circuit. ECM/PCM11-12'l
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Troubleshooting
Diagnostic Trouble Code (DTCI Chart (cont'd)
*: These DTCS will be indicated by the blinking o{ the Malfunction Indicator Lamp (MlL) with the SCS service connector
connected.**: The E (El*s indicator light and the Malfunction Indicator Lamp {MlL) may come on simultaneously,*1; A/T *3: '97 model *5: '99 - 00 models*2: MlT *4: '98 model
11-76
DTClMlL indicationlDetection hemProbable Caus.Page
P0137(63)Secondary Heated Oxygen SensorCircuit Low Voltage{Sensor 2)
Shon in Secondary HO2S (Sensor 2) circuatSecondary HO2S (Sensor 2)ECM/PCM
'n-1t7
P0138 (63)Secondary Heated Oxygen SensorCircuit High VoltageOpen in Secondary HO2S (Sensor 2) circuitSecondary HO2S (Sensor 2)EC|\il/PCM11118
P0139{63)Secondary Heated Oxygen Sensor
lSensor 2i
Secondary HO2S (Sensor 2)11-120
P0141 (65)Second6ry Heated Oxygen Sensor HeaterCircuit Malfunction(Sensor 2)
Open orshon in Secondary HO2S (Sensor 2)heater circuitEC|V/PCtu11't2l
P0r71 (45)
System Too LeanFuel supply systemPrimary HOzS (Sensor 1)
Contaminated fuel
Exhaust leakage
11124
P0112 (45)
System Too RichFuel supplv systemPrimary HO2S (Sensor 1)
Contaminated fuel11 124
and
Po3ol ltr \P0302 112 |P0303 173 iP0304 \74 t
Random Mistirelgnition systemFuel supply system
IAC valveContaminated fuelLack of fuel
11-126
P0301 /71 \P0302 112 |P0303 173 |P0304 \7 4l
- Cylinder 1- Cylinder 2Cylinder 3- Cylinder 4Misfire Detected
Fuel injectorFuel injector circuitlgnition system't't 127
P0325*5{23)Knock Sensor {KS) Circuit MalfunctionOpen or shon in Knock Sensor (KS) circuitKnock Sensor (KS)ECM/PCt\411-130
P033s{4}Crankshaft PositionSensor CircuitCrankshaft Position SensorCrankshaft Positaon Sensor circuitE Cl\,l/PC l\,'!11-131
P0336(4)Crankshaft Position SensorRange/PerformanceCrankshaft Position SensorTiming belt skipped teeth11,131
P0420{67)Catalyst System Efficiency BelowThresholdThree Way Catalytic convenerSecondary HO2S {Sensor 2)'t1-200
P0441*3 (92)
Evaporative EmissionControlSystemInsulficient Purge Flow
EVAP Purge Control Solenoid valveEVAP Purge Control Solenoid valve circuitThrottle gody (purge port)TubingPCM
'It 205
P0451*5FuelTank Pressure Sensor CircuitBange/PerformanceFuel Tank Pressure SensorECM/PCMt't-208
(91iFuel Tank Pressure SensorCirclit Low InputOpsn orShort in FuelTank Pressure Sensor circuitFuel Tank Pressure SensorECM/PCt\411-209
P0453*r.5 {91)FuelTank Pressure Sensor CircuitHigh InputOpen in Fuel Tank Pressure Sensor circuitFuel Tank Pressure SensorECt /PCt\.111-211
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DTC(MlL indicationlDotection ltomProbable CausePage
P0500 t17)*,
Vehicle SpeedSensor CircuitMalfunction
Vehicle Speed SensorVehicle Speed Sensor circu itECtVI1 1-135
P0501 l17J*1
Vehicle SpeedSensor CircuitMalfunction
Vehicle Speed SensorVehicle Speed Sensor circuitPCM11-135
P0505 (14)ldle ControlSystemMalfunction
IAC valveThrottle BodyFast idle thermo valve*11 ']- 150
P0700P0715PO720P0730P0740P0753P0758
AutomaticTransaxle
Section l4
P1106 (13)BarometricPressure CircuitRange/Performance Problem
ECM/PCM (Baro sensor)
11-137
P1107 (13)BarometricPressure CircuitLow InPut
. ECM/PCM {Baro sensor)11-137
P1108 (13)BarometricPressure CircuitHigh Inpur
ECM/PCM {Baro sensor)11,137
P1121 (7)Throttle PositionLower ThanExpected
. TP sensor11-109
P1122 (7)Throttle PositionHigher ThanExpected
' TP sensor1 1-'109
P112a (5)Manifold AbsolutePressure Lower ThanExpected
. MAP sensor11-94
P1129 (5)Manifold AbsolutePressure HiqherThanExpected
' MAP sensor1l-94
P1297 (20)Electrical LoadDetector CircuitLow Input
Electrical Load DetectorElectrical Load Detector circuitECM/PCM1 1- 138
P1298 (20)Electrical LoadDetector CircuitHigh Input
Electrical Load DetectorElectrical Load Detector circuitECM/PCM11-140
P1300'3
P0301P0302P0303P0304
7l721314
Random lvlisfirelgnition systemFuel supply systemMAP sensorIAC valveContaminated fuelLack offuel
11-126
*: These DTCS will be indicated by the blinking of the Malfunction Indicator Lamp {MlL} with the SCS service connector
connected.**:The E (E])+s indicator light and the Malfunction Indicator Lamp (MlL) may come on simultaneously.*1:A,./T "3: '97 model +5: '99 - 00 models*2: M/T *4:'98 model
{cont'd)
11-77
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Troubleshooting
Diagnostic Trouble Code (DTCI Ghart (cont'd)
r: These DTCS will be indicated by the blinking oJ the Malfunction Indicator Lamp (MlL) with the SCS service connectorconnected.**: The Di (E)*5 indicator light and the Malfunction tndicator Lamp (MlL) may come on simultaneously.*1: A[f *3;'97 model *5: '99 - 00 models*21M/f *4: '98 model
11-78
DTC
{MlL indication}Detection ltemProbable CausePagc
P1336 154)Crankshaft SpeedFluctuation SensorIntermittent Interruption
. CKF sensor
11-142
P1337 i54)Crankshaft SpeedFluctuation SensorNo Signal
CKF sensorCKF sensor circuitECM,FCM11-142
P1359 (8)Crankshaft Position/Too DeadCenter Sensorrcylinder PositionConnector Disconnection
' CKP/TDC/CYP sensor circuit11-146
P1361 (8)Top Dead CenterSensor IntermittentInterruption11-131
P1362 (8)Top Dead CenterSensor No SignalTDC sensorTDC sensor circuitECM/PCM11-131
P1381 (9)Cylinder Position SensorIntermittent Interruption
. CYP sensor11-131
P1382 (9)Cylinder Position SensorNo SignalCYP sensorCYP sensor circuitECM/PCM11-131
P1456n.* {90}
Evaporative EmissionControl System Leak Detected(FuelTank System)
Fuelfill capVacuum connectionFueltankFuel tank prossure sensorEVAP bypass solenoid valveEVAP two way valveEVAP control canister vent shut valveEVAP control canisterEVAP purge controlsolenoid valve
11-213
Pr457n.s {90)
Evaporative EmissionControl System Leak Detected(EVAP Control Canister Svstem)
Vacuum connectionEVAP control canisterFuel tank pressure sensorEVAP bypass solenoid valveEVAP two way valveEVAP control canister vent shut valveFueltankEVAP purge controlsolenoid valve
11-219
P1508 (14)ldle Air ControlValve CircuitFailure
IAC valveIAC valve circuitECM/PCM11-152
Pr607(-)Engine Control Module,PowertrainControl Module Internal CircuitFailure A
. ECM,FCM11-147
P1705P1706P1753P1758P1768
AutomaticTransaxle
Section '14
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PGM-FI System
System Description
INPUTS
CKP/TDC/CYP Sensor
CKF Sensor
MAP Sensor
ECT Sensor
IAT Sensor
TP Sensor
Primary HO2S
Secondary H02S
vss
KS*5
BARO Sensor
ELD*6
Starter Signal
ALT FR Signal
Air Conditioning Signal
Ay'T Gear Position Signal*1
Baftery Voltage (lGN.1)
Brake Switch Signal
PSP Switch Signal
Fuel Tank Pressuae Sensor*4. *5
Countershaft Speed Sensor*1
Mainshaft Speed Sensor*r
OVER-DRIVE Switch Signal*s
ENGINE CONTROL MODULE (ECM)/
POWERTRAIN CONTROL MODULE (PCM) OUTPUTS
|iuel 1"j""- Th,rhg ""d Drrafr";-l
Et*-.nt"tdt"cont.orl
to,r*,c;;trffi;]
l.----.---:. .Lrgnrnon |lmrng Lonrror I
Ecir/PcM B*k',p Fr""il]
m;"t-ll-r*'io*l
Fuel Injectors
PGM-Fl Main Relay (Fuel Pump)
MIL
IAC Valve
Ay'C Compressor Clutch Relay
Radiator Fan Relay
Condenser Fan Relay
ALT
tcM
EVAP Purge Control Solenoid
Valve
Primary HO2S Heater
Secondary H02S HeaterEVAP Bypass Solenoid Valve*a *5
EVAP Control Canister Vent Shut
DLC
Lock-up Control Solenoid Valve*l
Shift Control Solenoid Valve*1
Ay'T Clutch Pressure Control
Solenoid Valve*1
D4 Indicator Light'1 *3, *a
D Indicator Light,l *5
OVER-DRIVE OFF Indicator
Lighl*t *:
*1: A/T {3:'97 model'2: M/f +4:'98 model*5: '99 - 00 models"6: USA
PGM-Fl System
The PGM-Fl system on this model is a sequential multiport fuel injection system.
Fuel iniecior Timing and Duration
The ECM/PCM contains memories for the basic discharge durations at various engine speeds and manifold pressure. The
basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors
to obtain the final discharge duration.
ldle Air Control
ldle Air Control Valve (lAC Valve)
When the engine is cold, the Ay'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
o The ECM/PCM contains memories for basic ionition timing at various engine speeds and manifold air flow rates.
lgnition timing is also adjusted for engine coolant temperature.
. A knock control system was adopted which sets the ideal ig nition timing for the octane rating of the gasoline used.*s
Other Control Funstions
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 (ll). the ECMiPCM suppli€s ground to the PGM-FI main relay that
supplies current to the fuel pump for two seconds to pressurize the fuel system.
. When the engine is running, the ECM/PCM supplies ground to the PGM-FI main 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.
1 1-80
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