Idle control system HONDA CR-V 1999 RD1-RD3 / 1.G Workshop Manual

System Description
Vacuum Connections (cont'dl
'97 model:
ENGINECOOLANT
ITr|ll
O PRIMARY HEATED oxYGEN sENsoR {PRIMARY Ho2s,SENSOR lt
O SECONDARY HEATED oxYGEN sENsoR {SECoNDARYHO2S. SENSOR 2l€) MANIFOLD ABSOLUTE PRESSURE (MAPI SENSOR@ ENGINE cooLANT TEMPERATURE {EcT} sENsoRO INTAKE AIR TEMPERATURE (IAI} sENsoR@ CRANKSHAFT SPEED FLUCTUATION ICKFI SENSORO |DLE ArR coNTRoL {tAc)vALvE@ FAST IDLE THERMo vALvEO THRoTTLE EoDY ITB)@ FUEL INJEcTonO FUEL PULSATIoN oAMPER@ FUEL FILTEn(} FUEL PRESSURE REGULATOR
FUEL PUMPFUEL TANKFUEL TANK EVAPORATIVE EMISSION (EVAPIVALVEAIR CLEANERRESONATORPOSITIVE CRANKCASE VENTILATION {PCVI VALVEEVAPORATIVE EMISSION {EVAP} PURGE CONTROLSOI.'ENOID VALVEEVAPORATIVE EMISSION {EVAP) CONTROL CANISTEREVAPORATIVE EMISSION {EVAPI TWO WAY VALVETHREE WAY CATALYTIC CONVERTER (TWC)
@(D(D
o@(}
@
@@@
1 1-10
www.emanualpro.com

System Description
I
I
I
Vacuum Connections (cont'dl
'98 model:
C PRIMARY HEATEO OXYGEN SENSOR (PRIMARY HO2S,
SENSOR 1)(, SECONDARY HEATEO OXYGEN SENSOR ISECONDARYHO2S, SENSOR 2)(!)\\\\ss\SNBSS\\\ETRESS\RE\\NQ\SE\SSR
G) ENGINE COOLANT TEMPERATUBE (ECT) SENSOR
O INTAKE AIR TEMPERATURE {IAT} SENSOR
@ CRANKSHAFT SPEED FLUCTUATION (CKFI SENSOR
O IDLE AIR CONTROL (IAC) VALVE
@ FAST IDLE THERMO VALVE (A/T)
O THROTTLE BODY (TBI(0) FUEL INJECTOR.1' FUEL PULSATION DAMPER.14 FUEL FILTER(i FUEL PRESSURE REGULATOR14 FUEL PUMP(D FUEL TANK@ FUEL TANK EVAPORATIVE EMISSION {EVAPI VALVE
C] AIR CLEANER(O RESONATOR1iC POSITIVE CRANKCASE VENTILATION (PCV) VALVE
6 \$REE$IN gN NL$\C CON\ER\ER (TNC\
ti q rpos,xr E qN
ssros \E aP cqN\RoLcaNtsr€R
@ EVAPORATIVE EMISSION IEVAP) PURGE CONTROL
SOLENOID VALVEq3 EVAPORATIVE EMISSTON IEVAP} CONTROL CANISTER
VENT SHUT VALVE
@ EVAPORATIVE EMISSION (EVAP) TWO WAY VALVE
€i EVAPORATIVE EMISSION {EVAP) BYPASS SOLENOID
VALVE
€9 FUEL TANK PRESSURE SENSOROi EVAPORATIVE EMISSION {EVAP) THREE WAY VALVE
Qd PURGE JOINT
G/T only)
f
-i*'";-t
COOLANT Jt
U
11-12
www.emanualpro.com

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
www.emanualpro.com

Troubleshooting
Troubleshooting Procedures (cont'dl
Symptom Chart
Listed below are symptoms and probable causes for problems that DO NOT cause the Malfunction Indicator Lamp (MlL) tocome on. lf the MIL was reported on, go to page 11-60.Troubleshoot each probable cause in the order listed (from left to right) until the symptom is eliminated,The probable cause and troubleshooting page reference can be found below.
Other Probable Causes for an engine that will not start:- Compression- Intake air leakage- Engine locked up- Timing belt- Starting system- Overheating- Battery
SYMPTOMPROBABLE CAUSE
Engine will not sta rt4, 2,3,5,20, 't5, 1
Hard starting2, 4, 12,17, 14, 't9
Cold fast idle too low7, a,9, 6, 17
Cold fast idle too high7,8,9,11,10
ldle speed fluctuates9,7,8, 't1, 10
Misfire or rough runningTroubleshoot for misfire on pages '11-126, 1|21LOl/\/ power2, 10,11, 13, '17, 18,20
Engine stalls2, 4, 12,1,20,9,5, 't6
Probable Cause List (For the DTC Ch8rt, see page ll-75.)
Probable CausePageSystem
Engine controt ruoaute (ecvtffi'I11-42
I 1-178Fuel oressure
PGM-Fl main relav
lgnition system
Crankshatt Position/Top Dead Center/Cylinder position sensor circuit
Intake Air Temperature (lAT) sensor ctrculr
ldle Air Control (lAC) Vatve
Fast idle thermo valve
ldle speed adjustment
Throttle body
Throftle cable
Manifold Absolute P."""rr"ffi
Throftle Position (TP) sensor
Barometric pressur" (gnno-
Ay'T gear position signal
Brake switch signal
Air Cleaner
Three Way Catalytic Converter (TWC)
Evaporative emission (EVAP) control
Contaminated fuel
1 1- 187
Section 4
5't1-'t31,146
6I 't-95
711-152
81'l-168
1 1- 169
1011-196'1111-'194
12'1 'l -90
1 1- 103
1411-137
15Section 14
161 1- 166
17r 1-194
181 1,199'1911-203
20
11-64
www.emanualpro.com

Troubleshooting
Troubleshooting Procedures (cont'd)
DataDescliptionOperating ValueFreezo Data
HO2S
Feedback
Loop Status
Loop status is indicated as "open" or "closed".
Closed: Based on the HO2S output, the ECM/pCM deter-mines the airlfuel ratio and controls the amount ofinjected fuel.
Open: ignoring HO2S output, the ECM/pCiM refers to sig,nals from the TP, MAP, and ECT sensors to control theamount of injected fuel.
At idle speed: closed
YES
Short Term
Fuel Trim
The airlfuel ratio correction coefficient for correcting theamount of injected fuel when HO2S feedback is in theclosed loop status. When the signal from the HO2S isweak, short term fuel trim gets higher, and the ECM/PCMincreases the amount of injected fuel. The airlfuel ratiogradually gets richer, causing a higher HO2S output.Consequently. the short term fuel trim is lowered. andthe ECM/PCM reduces the amount of injected fuel.This cycle keeps the airfuel ratio close to the stoichio-metric ratio when in closed looD status.
t:20y"
YES
Long Term
Fuel Trim
Long term fuel trim is computed from shon term fueltrim and indicates changes occuring in the fuel supplysystem over a long period.
lf long term fuel trim is higher than 1,00. the amount ofinjected fuel must be increased. lf it is lower than L00.the amount of injected fuel must be reduced.
! 20%
Intake Air
Temperature
(IAT)
The IAT sensor converts intake air temperature into volt-age and signals the ECrU/PCM. When intake air tempera-ture is low, the internal resistance of the sensorincreases, and the voltage signal is higher.
With cold engine:
Same as ambient temper-
ature and ECTYES
Throttle
Position
Based on the accelerator pedal position, the openingangle of the throttle valve is indicateo.At idle speed:
approx. 10%
lgnition
Timing
lgnition timing is the ignition advance angle set by theECM/PCM. The ECM/PCM matches ignition timing to thedriving conditions.
At idle speed: 16'1 4.
BTDC with the SCS ser-
vtce connector connected.
NO
Calculated
Load Value(cLV)
CLV is the engine load calculated from the MAp data.At idle speed:
2A - 410/o
At 2,500 rpm with no load:
13 - 260/o
YES
_
1 1_66
www.emanualpro.com

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
www.emanualpro.com

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
www.emanualpro.com

Fuel Cut-off Control
. During deceleration with the throttle valve closed, current to the fuel injectors iscutoffto improvefuel economyat
speeds over 970 rpm ('97 - 98 models), 920 rpm ('99 - 00 modelsl.
. Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm ('97 - 98 models), 6900 rpm ('99 - 00
models), regardless of the position of the throttle valve, to protect the engine from over-rewing.
With Ay'T model. the PCM cuts the fuel at engine speeds over 5,000 rpm when the vehicle is not moving.*'
4,./C Comoressor Clutch Relav
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 a smooth transition to the Ay'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,
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.
PCM Fail-saf e/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-pre
grammed value for that sensor that allows the engine to continue to run.
2. Back-up 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 IMalfunction Indicator Lamp (MlL)l
When an abnormality occurs in a signal from a sensor, the ECM/PCM supplies ground for the MIL and stores the DTC
in erasable memory. When the ignition is initially turned on {ll), the ECM/PCM supplies ground for the MIL for two
seconds to check the MIL bulb condition.
4. Two Trio Detection Method
To prevent false indications, the Two Trip Detection Method is used for the HO2S*1, fuel metering-related. idle control
system, ECT sensor 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 (ll) 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 {'97 model)
A "Driving Cycle" consists of starting the engine, beginning closed loop operation, and stopping the engine. lf misfir-
ing that increases emissions or EVAP control system malfunction is detected during two consecutive driving cycles.
or TWC deterioration is detected during 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.
*1: '97 - 98 models*2: '99 - 00 models
5.
www.emanualpro.com

ldle Control System
System Description
The idle speed of the engjne 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 by the
ECM/PCM. When the lAc valve is activated, the valve opens to maintain the proper idle speed.
YEL/ From PGM'FI
BLK TMAIN RELAY
VARIOUSSENSORS
4.
IAC VALVE
INTAKE MANIFOLD
After the engine starts, the IAC valve opens for a certain time. The amount of air is increased to raise the idle speed
about 150 - 300 rpm.
when the cootant temperature ts row, the lAc valve is opened to obtain the proper fast idle speed The amount o{
bvoassed air is thus controlled in relation to the engine coolant temperature
When the idle speed is out o{ specification and the scan tool does not indicate Diagnostic Trouble Code (DTC) P0505
or P1508, check the following items:
. Adjust the idle speed (see page 11-169, 170)
. Air conditioning signal (seepagell-1551
. ALT FR signal (see page 1l-159)
. Starter switch signal (see page 11-16'1)
. A,/T gear position signal (see section 14)
. PSP switch signal (seepagell-162)
. Brake switch signal (see page 11-165)
. Fast idlethermovalve (see page'11 168)
. Hoses and connecttons. IAC valve and its mounting O-rings
lf the above items are normat, suDslitute a known-good IAC valve and readjust the idle speed {see page 11-169, 170)
lf the idle speed still cannot be adjusted to specification (and the scan tool does not indicate DTC P0505 or Pl508)
after IAC valve reolacement, substitute a known-good ECM/PCM and recheck lf symptom goes away' replace the
original ECM/PCM.
11-149
www.emanualpro.com

ldle Control System
ldle Control System
I P0505 | The scan tool indicates Diagnostic T.ouble Code (DTCI PO5O5: ldlecontrol svstem mattunction.
NOTE: lf DTC P1508 is stored at the same time as DTC P0505, troubleshoot DTC P1508 first. then troubleshoot DTC p0505.
Possibls Cause
. IAC valve mechanical malfunction. Throttle body clogged port, improper adlustment. Intake manifold gasket leakaging. Intake air hose loose leakaging. Vacuum hose leakaging
a ECT sensor incorrect output. Throttle Position sensor incorrect output
Troubleshooting Flowchart
The MIL has been reDorted on.DTC P0505 is sto.ed.
Problem verificationi1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator Ian comes on, thenlet it idle.2. With the scan tool, check thelollowing items.- Throttle position should beapprox. 10% with the throt-tle {ully closed.- Engine coolant temperature shorJld be 194 - 205'F(90 - 96"C).lf they are not within thespec., repair the faulty sen-sor circuit.3 Check the engine speed atidle with no-load conditions:headlights, blower fan. reardefogger, radiator lan, and airconditioner are not operaling,
Inte.mittent failure. syltem is OKat this time.ls it 750 {730)* i 50 rpm?
ls il 700 (680)' rpm or less?
{To page 11-151)(To page 1'l-151)
l:'99 - 00 models
www.emanualpro.com