1997 HONDA CR-V engine controls

Fuel and Emissions
Special Tools ...................... 11-2
Component Locations
lndex ...................... ....,.... 11-3
Svstem Description
Vacuum Connections ...........,....,.,................. 1 1-9
Electrical Connections ................................... 1 1-15
System Connectors .,.,,.,............................,.,. 1 1-36
Troubleshooting
Troubleshooting Procedures,.,..................... 11-60
Engine Control Module/Powertrain ConttolModule Terminal Arrangement .............., 11-67
Diagnostic Trouble Code Chart .................... 1 t-75
How to Read Flowcharts .......,.....,.,............... I 1-79
PGM-Fl System
System Description .................,.,.,,,............... 1 1-80
Troubleshooting Flowcharts
Engine Control Module/PowertrainControl Module ........11-52
Manifold Absolute Pressure Sensor ............. 11-90
Intake Air Temperature Sensor .................... 1 1-95
Engine Coolant Temperature Sensor .,..,.,.... 1 1-99
Throttle Position Sensor ...........,.....,.,.,..,...... I 1'103
Primary Heated Orygen Sensor (Sensor 1) ... 11-110
Secondary Heated Oxygen Sensor{Sensor 2l .................. 1 1-117
Heated Oxygen Sensor Heater ..................... 11-121
Fuef Supply System ......11-124
Random Misfire ,....,.,..... 11-126
Mistire Detected in One Cylinder .....-........... 11-128
Knock Sensor ................ 11-130
CKP/TDC/CYP Sensor .................................... 1 1-131
Vehicle Speed Sensor ...............................,.... 1 1-135
Barometric Pressure Sensor .....,...,...,.,,........ 1 1-137
Electrical Load Detector ...,.,.......................... 1 1-138
CKF Sensor ................,.,, '11-112
ECM/PCM lnternaf Circuit ............................. 11'117
HO2S Replacement .,.,.,. 11-148
ldle Control System
System Description ............ 11-149
Troubleshooting Flowcharts
ldle Control System ...... 11-150
fdle Air Control Valve ......................,............. 11-152
Air Conditioning Signal ................................. I 1-155
Alternator FR Signal ...................................... 1 1-159
Starter Switch Si9na1 .................................... t l-161
Power Steering Pressure Switch Signal ...... 11-162
Brake Switch Si9na1 ...................................... 11-166
Fast ldle Thermo Valve .,.,.............................,.,.,. 11-168
ldle speed setting .............. 11-169
Fuel Supply System
Fuel Lines ............................ 11-171
Fuef Tube/Ouick-Conneci Fittings ..................... 11 -175
System Description ............ 11-178
Fuel Pressurg ...................... 11-178
Fuel Iniectors ................,..... 11-179
Fuel Pressure Re9u1ator .............................,.,...., f 1-181
Fuef Fifter ....,.,.,.,,,,.,............11-142
Fuel Pump ........................... 11-183
Fuel Gauge .......................... 11-184
Fuel Gauge Sending Unit ................................... I 1-185
Low Fuel Indicator System ...........,.,..,............... 1 1-185
PGM-FI Main Relay ............. 11-187
Fue|Tank................ ............. 11-191
Intake Air System
System Description ............ 11-193
Air Cleanel ,.,.,..................... 11-194
Throttle Cable ..................... 11-194
Throttle Body........ .............. 11-196
Emission Control System
System D$cription ...,....,.,. 11-199
Tailpipe Emission ............... 11-199
Three Way Catalytic Converter ..................,.,...,, 11-199
Positive Crankcase Ventilation System .,.,,,,.,.., 11-2O1
Evaporative Emission Controls .........,.,.,............ 11-203
www.emanualpro.com

Component Locations
lndex
'97 - 98 models:
MANIFOLD ABSOLUTEPRESSURE IMAP} SENSORTroubleshooting, Page 1 1-90
THROTTLE POSITION (TP}
SENSORTroubleshooting, page 1 1-103
toLE AtR CONTROL llAcl VAI-VE
Troubleshooting, page 1 1-152
EVAPORATIVE EMISSION (EVAP)
CONTROL CANISTER VENT SHUTVALVE t'98 mod€llTroubleshooting, page 11'213
INTAKE AIR TEMPERATUREIIATI SENSORTroubleshooting. page 1 'l -95
ELECTRICAL LOADDETECTOR IELD) (USA modol)Troubleshooting, page 1 1-138
VEHICLE SPEEDSENSOR (VSS)
Troubleshooting,page 11'135
CRANKSHAFTPOSTTtON/
POWER STEERING PRESSURElPsPl swtrcHTroubloshooting, page 1 1-162
TOP OEAD CENTER/CYLINDERPOStTtON{CKP/TDC/CYP} SENSOR(Built into the distributor)Troubleshooting, page 1 l-131
CMNKSHAFT SPEEDFLUCTUATION ICKF} SENSORTroubleshooting. page 1'!-142
ENGINE COOLANTTEMPERATUREIECTI SENSORTroubleshooting, page 11 99
EVAPORATIVEI€VAP) PURGE CONTROLSOLENOID VALVETroubf eshooting, page 1 1'2o5, 213
(cont'd)
11-3
www.emanualpro.com

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
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

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
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

Powertrain Control Module Terminal Arrangement -'97 Model
FCM CONNECTOR A (32P)NOTE: Standard battery voltage is 12 V.
Wire side of lemale terminals
f€rminalnumlreJWirecolor
Telminalnama
DescriptionSignal
YELlNJ4 (No.4 FUELINJECTOR)Drives No. 4 {uel injector.With engine running: duty controlled
2BLUlNJ3 (No.3 FUELINJECTOR)Drives No. 3luel injector.
REDlNJ2 {No.2 FUELINJECTOR)Drives No.2 tuel injector.
BRNlNJl (No. l FUELINJECTOR)Drives No. 1 fuel injector.
5BLK WHTSO2SHIC (SECONDARY
HEATED OXYGEN SENSOR HEATER CONTROL)
D ves secondary heated oxygensensor heater.With ignition switch ON {ll): battery voltageWith fully warmed up engino running: dutycontrolled
6BLKAr'YHT
PO2SHTC (PRIMARY
HEATED OXYGENSENSOR HEATERCONTROL}
Drives primary heated oxygensensor heater,With ignition switch ON lll): battery voltagewith fully warmed up engine running: dutycontroll6d
I8RN/BLKLGl (LOGIC GROUND}Ground forthe PCM control circuit.Less than 1.0 V at all times
10BLKPG1 lPOWER GROUND}Ground for the PCM power circuit.
l1YEUELKIGPl lPOWER SOURCE}Power source for the PCM controlcircuit.
With ignition switch ON (ll): battery voltageWith ignition switch OFF: 0 V
12BLI(BLUIACV {IDLE AIRCONTROL VALVE}Drives IACV.With €ngine running: duty controlled
REDryEL
PCS (EVAP PURGECONTFOL SOLENOIDVALVE)
Drives EVAP purge controlsolenoid valve.
With engine running, engine coolantbelow 154'F (68"C): battery voltageWith engine running, engine coolantabove 154"F (68"C): duty controlled
16GRN/VELFLR (FUEL PUMP RELAY)Drives Iuel pump relay.0 V for two seconds after turning ignition
switch ON lll), then battery voltage
118LI(REDACC (A,/C CLUTCHRELAY}Drives Ay'C clutch relay.With comoressor ON: 0 VWith compressor OFF: baftery voltage
18GRN/ORNMIL (MALFUNCTION
INDICATOR LAMP}Drives MlL.With MIL turned ON: 0 VWith MIL turned OFF: baftery voltage
19*WHT/GRNALTC (ALTERNATOR
CONTROL}Sends alternator control signal.With tully warmed-up engine running:
battery voltageDuring driving with smallelectrical load:0 '
20YEUGRNICM (IGNITION CONTROLMODULE)Sends ignition pulse.With ignition switch ON (ll): baftery voltageWith engine running: pulses
22BRN/BLKLG2 (LOGIC GROUND}Ground tor the PCM control circuit.Less than 1.0 V at alltimes
23BLKPG2 {POWER GROUND}Ground lor the PCM power circuit.
24YEUBLKIGP2 {POWER SOURCE}Power source for the PCM controlcircuit.
With ignition switch ON (ll): battery voltage
With engine switch OFF: 0 V
27GRNFANC (RADIATOR FANCONTROL)Drives radiator {an relay.With radiator fan running: 0 VWith radiator fan stopped: baftery voltage
*: USA
{cont'd)
11-67
www.emanualpro.com

Troubleshooting
PCM CONNECTOR B I25PI
Powertrain Control Module Terminal Arrangement -'97 Model (cont'dl
Wire side of female terminalsPCM CONNECTOR B I25P}NOTE: Standard battery voltage is l2 V.
1 1-68L
TerminelnumbercolorTerminalnameOescriptionSignal
1LS 1A/T CLUTCHPRESSURE CONTROLSOLENOID VALVE -)
Drives A,/T clutch pressure controlsolenoid valveWith ignition switch ON (ll): duty con-trolled
2REDLS + (A"/T CLUTCHPRESSURE CONTROLSOLENOID VALVE +)
Drives A,/T clutch pressure controlsolenoid valveWith ignition switch ON (ll)r duty controlled
38LU//EL
SHA (SHIFT CONTROLSOLENOID VALVE A)Drives shift control solenoid valve A.In 2nd, R position. in 2nd and 3rd gear inD4, D3 position: Battery voltageIn lst gear in D4, D3 position, in 4th gear
in D4 position: 0 V
4GRN/BLKLC B (LOCK-UP CONTFOLSOLENOID VALVE B)Drives lock-up control solenoidvalve B,With full lock-up; Baftery voltageWith half lock-up: duty controlled
5YELLC A (LOCK.UP CONTROLSOLENOID VALVE A)Drives lock-up control solenoidWith lock'up ON: battery voltageWith lock-up OFF:0 V
IPNKATPD3 (Ay'T GEARPOSITION SWITCH}Detects A/T gear position switchsignal. _
In D3 position:0 Vln any other position: battery voltage
11GRN/VVHT
SHB (SHIFT CONTROLSOLENOID VALVE 8}Drives shift control solenoid valve B.In 1st, 2nd position, in 1st and 2nd gear inD4, D3 position: Battery voltageIn R position, ;n 3rd gear in 04, D3, in 4thgear in D4 position: 0 V
12WHT/BEDILU (INTERLOCK
CONTROL UNITiDetects interlock control unh signal.With ignition switch ON (ll)and brakepedal depressed: battery voltage
GRN/BLKD4IND (04 INDICATORLIGHT}Drives Dl indicator light.With D4 indicator light turned ON: batteryvoltageWith D4 indicator light turned OFF: 0 V
14NMSG (MAINSHAFT
SPEED SENSOR GROUND}Ground tor mainshaft speed sensor.
REDNM (MAINSHAFT SPEEDSENSOR)Detects mainshaft speed sensorsrgnal,With engine running: pulses
16ATPR (A"/T GEARPOSITION SWITCH)Detects A/T gear position switchsrgnal.InRposition:0VIn any other position: battery voltage
1'lBLUATP2 (A./T GEARPOSITION SWITCH)Detects A/T gear position switchsrg nal,In 2nd position: 0 VIn any other position: battery voltage
18BRNATP1 (4,,/T GEARPOSTTTON SWTTCH)Detects A/T gear position switchsrg nal,ln lst position: 0 VIn any other position: battery voltage
22GBNNCSG (COUNTERSHAFT
SPEED SENSOR GROUND)Ground tor countershaft speedsensor,
23BLUNC (COUNTERSHAFT
SPEED SENSOR)Detects countershaft speed sensorsrgnal.With agnition switch ON (ll), and lrontwheels rotating: pulses
24YELATPD4 (M GEARPOSITION SWITCH)Detects A,/T gear position switchsrgnal.In D4 positionr 0 VIn any other position: battery voltage
25LT GRNATPNP {A/T GEARPOSITION SWITCH)Detects A/T gear position switchsignal.In park or neutral:0 VIn any other position: about 5 V
www.emanualpro.com