Brake switch HONDA CR-V 2000 RD1-RD3 / 1.G Workshop Manual

Engine Electrical
Speciaf Tools ............. 4-2
Starting System
Component Location Index ............ 4-3
Circuit Diagram ................................ 4-4
Starter Test ........... 4-5
Starter Solenoid Test ...................... 4'5
Starter Replacement ....................... 4-7
Field Winding Test ........................... 4-7
Starter Overhaul ............................,. 4-8
Brush Inspection ...........................,., 4-9
Overrunning Glutch Inspection ...... 4-9
Armature lnspection and Test ........4-10
Brush Holder Test ............................ 4-12
Starter Reassemb|y ......................... 4-1 2
Perf ormance Test ............................. 4- 1 3
lgnition System
Component Location Index ............ 4-14
Circuit Diagram ................................ 4-15
lgnition Timing Inspection and
Setting .......................................... 4-16
Distributor Replacement ........,........ 4-17
Distributor Overhaul .............,,......... 4-18
lgnition Control Module (lCM) Input
Test ..............................,................ 4-19
fgnition Coil Test .............................. 4-2O
lgnition Wire Inspection and
Test ............................................... 4-20
Spark Plug Inspection ..................... 4-21
-+
ENGINE
Charging System
Component Location Index ............ 4-22
Circuit Diagram ....................,........... 4-23
Troubleshooting .............................. 4-24
Alternator Replacement ..........,....... 4-30
Alternator Overhaul .......,,................ 4-31
Rectifier Test .........4-32
Alternator Brush Inspection ........... 4-32
Rotor Slip Ring Test ........................ 4-33
Stator Test ............. 4-33
Alternator Belt Inspection and
Adiustment ........4-34
Gruise Control
Component Location Index .,,,........ 4-36
Circuit Diagram ................................ 4-37
Control Unit Input Test ................... 4-38
Main Switch Test/Replacement ..... 4-40
Set/Resume Switch Test/
Replacement .......................,........ 4'40
Actuator Test ....,,., 4-41
Actuator Replacement ...............,.... 4-42
Actuator Cable Adiustment ............ 4-43
Clutch Switch Test .......................... 4-43
Brake Switch Test .................. .......... 4-44
Actuator Solenoid Test .............. ...,. 4-44
Actuator Disassembly ..................... 4-45
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Disconnest the lilP connector from the control unit.
Csvity WireTest condition
R€conn€ct tho 14P connGctor to the control unit.
Test: Desired resultPossible cause it result is not obtained
BRNAr'VHTUnder all conditionsCheck for resistance to groundl
There should be 80 - 120 o.
Faulty actuator solenoid
Poor ground (G202)
An open in the wire1BRNUnder all conditionsCheck for resistance to groundl
There should be 40 - 60 0.
11BRN/BLKUnder all conditionsCheck for resistance to ground:
There should be 70 - 110 O.
2GRY
lgnition switch ON (ll),
main switch ON and
brake pedal depressed,
then released
Check for voltage to ground:
There should be 0 V with the pedal
depressed and battery voltage with
the pedal released.
. Faulty brake switch. An open in the wire
BLKUnder all conditionsCheck for continuity to ground:
There should be continuity.
. Poor ground (G401). An open in the wire
5GRNMHT
Brake pedal depressed,
then released
Check for voltage to ground:
There should be battery voltage with
the pedal depressed, and 0 V with
the pedal released.
Blown No.52 1'15 Alfuse in the
under-hood fuse/relay box
Faulty brake switch
An open in the wire
LT GRN/
RED
Set button pushedCheck for voltage to ground:
There should be battery voltage.Blown No. 52 {'15 A} fuse in the
under-hood fuse/relay box
Faulty horn relay
Faulty sevresume switch
Faulty cable reel
An open in the wire7LT GRN/
BLK
Resume button pushed
10RED/BLU
lgnition switch ON lll)Attach to ground:
Cruise indicator light in the gauge
assembly should come on.
Elown bulbBlown No. 25 (7.5 A) tuse in theunder-dash fuse/relay box
Faulty dimming circuit in the gauge
assembly
An open in the wire
ELU^r'r'HT
lgnitjon switch ON {ll}and main switch ON;
raise the front of the
vehicle, block one wheel
and rotate the other
wheel slowly.
Check for voltage between the
ELUA/VHT @ and BLK O terminalsl
There should be 0 - 5 V or more-0 - 5 V or more repeatedly.
Faulty vehicle speed sensor (VSS)
An open in the wire
r3LT GRN
lgnition switch ON {ll}and main switch ONCheck for voltage to ground:
There should be battery voltage.
Blown No. 14 (7.5 A) fuse in theunder-dash fuse/relay box
Faulty main switch
An open in the wire
l4PNK
A'/T: Shift lever in E, EotE
lvl/T: Clutch pedal
releaseo
Check for continuity to ground:
There should be continuity.NOTE: There should be no continu-
ity when the shift lever is in otherpositions or when the clutch pedal is
oepresseo.
Faulty A/f gear position switch 1A,/TlFaulty or misadjusted clutch switch
fi{/r)Poor ground (G101)
An open in the wire
BLU
Start tho engine. turnthe main switch ON, anddrive the vehicle over 25
mph (40 km/h)with the
crurse control set
Check for voltage to ground:
There should be approx.5 V
. Faulty cruise control unit. Shod to ground
*: '98 - 00 models with Automatic Transmission.
4-39
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Cruise Control
Brake Switch Test
1. Disconnect the 4P connector from the switch,
2. Remove the brake switch.
Terminal side of maletermtnals
Check for continuity between the terminals accord-
ing to the table.
lf necessary, replace the switch or adjust pedal height
(see section 19).
{P CONNECTOR
Terminal
;;;;-t
15
RELEASEDO----o
PUSHEDo--o
4-44
ACTUATOR
Actuator Solenoid Test
1. Disconnect the 4P connector from the actuator.
Terminalside ofmale terminals
Check for resistance between the terminals accord-
ing to the table.
NOTE: Resistance will vary slightly with tempera-
ture; specified resistance is at 68"F (20"C).
VALVE
I
I
I
To VACUUMTANK
Terminal
il',",""*(t)
_\13
VENT SOLENOID
40-600o--o
VACUUM SOLENOIDo---o
30-500
SAFEW SOLENOID
40-600o----o
VACUUM
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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
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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
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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
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Troubleshooting
Powertrain Gontrol Module Terminal Arrangement -'97 Model (cont'd)
PCM CONNECTOR O {16PI
PCM CONNECTOR D (I6P)Wire side of f6male terminals
NOTE: Standard battery voltage is 12 V.
f.rminal
numbcrWir! colorT€rminal nam6DescriptionSignal
1RED/BLKTPS ffHROTTLE
POSITION SENSOR}
Detects TP sensor signal.With throttle fullv oDen: about 4.8 V
With throttle fullv closed: about 0.5 V
RE D,4/VHT
ECT (ENGINE COOLANT
TEMPERATURE
SENSOR
Detects ECT sensor signal.With ignition switch ON {ll): about
0.1 - 4.8 V (depending on engine
coolant temperature)
RED/GRN
MAP (MANIFOLD
ABSOLUTE PRESSURE
SENSOR)
Detects MAP sensor signal.With ignition switch ON (ll): about 3 V
At idle; about 1.0 V(depending on engine speed)
YEUREDVCCl (SENSOR
VOLTAGE)
Pow€r source for MAP sensor.With ignition switch ON (ll): about 5 V
With ignition switch OFF: 0 V
EG R N/WHT
BKSW (BRAKE
SWITCH)
Detects brake switch signal.With brake pedal released:0 V
With brake pedal depressed: battery
voltage
7WHT
PHO2S (PRIMARY
HEATED OXYGEN
SENSOR SENSOR 1)
Detects heated primary oxygen
sensor (sensor 1) signal.
With throttle fully opened from idle with
fully warmed up engine: above 0.6 V
With throttle quickly closed: below
0.4 v
8RED//E L
IAT (INTAKE AIR TEM.
PERATURE SENSOR)
Detects IAT sensor signal.With ignition switch ON lll): about
0.1 - 4.8 V (depending on intake air
temperaturel
10YEUBLUVCC2 (SENSOR VOLT-
AGEI
Provides sensor voltage.With ignition switch ON (ll): about 5 V
With ignition switch OFF: 0 V
11GRN/BLKSG2 (SENSOR
GROUND)
Sensor ground.Less than 1.0 V at all times
12GRN/WHTSGl (SENSOR
GROUND)
Ground for MAP sensor.Less than 1.0 V at all times
13RED/YE L
SHO2S SG(SECONDARY HEATED
OXYGEN SENSOR,
SENSOR 2 GROUND)
Ground for secondary heated
orygen sensor (sensor 2).
14WHT/RED
SHO2S (SECONDARY
HEATED OXYGEN
SENSOR, SENSOR 2)
Detects secondary heated
orygen sensor (sensor 2)
signal,
With throttle fully opened from idle with
fully warmed up engine; above 0.6 V
With throttle quickly closed: below
0.4 v
16*GRN/RED
EL (ELD)Detects ELD signal.With parking lights turned on at idle
about 2.5 - 3.5 V
With low beam headlights turned on
at idle: about 1.5 - 2.5V
1-70
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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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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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Vehicle Speed Sensor (VSSI
lPosoo-]-'. |posol l-'
'97 modol:
The scan tool indicates Diagnostic Trouble Code {DTC} P0500*'or P0501*r: A range/perfor-
mance in the Vehicle Speed Sensor (VSS) circuit. * I ; A/T*2i Mfi
FCM CONNECTORS
A t32Pl
LG1(BRN/BLK)
NOTE: Do not use the engine to turn thofront wheels with th6 rear wheels on theground. The 4WD system will engage andthe vehicle will suddenlv Iurch forward.
Wire side ot female terminals
LGl
{BRN/BLKI
(cont'd)
11-135
The MIL hes boen roported on.DTC m501 is 3tor€d.
Problom verificetion:1. Test'drive the vohicle.2. Check the vehicle speed withthe scan tool,
lntormittent tailure, rystom b OKat thia timo. Chock tor poor con-nection3 or 10o3o wires rt C129lvss) .nd rr rhe Pcfr4,
ls the correct speed indicated?
Chock for an open in tho PiCM:1. Turn the ignition switch OFF.2. Block the rear wheels and setthe parking brake.3. Jack up the lront of the vehicleand support it with saletystands.4. Turn the ignition switch ON (ll).
5. Elock the right front wheel andslowly rotate the left trontwheel by hand.6. Measure voltage betweenPCM connector terminals C18and A9.
Substitulc a known-good PCMand .och6ck. It symptom/indicd.tion go.a away, .cplaco tho origi-nel FCM.
Doesthe voltage pulse 0 Vand 5 V or battery voltage?
Check for a .hort in the PCM:L Turn the ignition switch OFF.2. Disconnect the PCM con'nector C (31P).
3. Turn the ignition switch ON (ll).
4. Elock the right front wheeland slowly rotate the left front
5. Measure vohage between PCMconnector terminals C18 andA9.
Substituto e known-good PCMand rochock. f rymptom/indica-tion goos rwry, roplsc. tho origi-nalFCM.
Doesthe voltage pulse 0 Vand 5 V or battery voltage?
- Repair short in the wirebetween the PCM lC18l,cruise control unit, speodo-meter, and VSS,- Repair opon in the wirebetween the PCM {C181 .ndrhe vss.- f wire is OK. tost lho VSS l3oosoction 231.
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