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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(From p!9.1r-221
ca32
**r2",-*JYEVGRN -1
YEvErK --
IBLU?'I'HT ___-I
GRN,/YEL -- IYEVGnN --
"* --1
PGII.FIUAIN RELAY
C56-2 //--\- trru^n -- -] ( , )_BLK - i ,/I - \_-,/
dL FUEL PUMP
11-23
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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
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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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NOTE:. When there is no Diagnostic Trouble Code (DTC) stored, the MIL will stay on if the SCSservice connector is connected and the ignition switch is on.. lf this svmotom is intermittent, check for:- A loose Fl E/M (15 Aifuse in the underdash tuse/relay box- A loose No. 13 FUEL PUMP {15 A) fuse in the under-dash fuse/relay box- An intermittent short in the wire between the PCM (C7) and the service check con-
- An intermittent short in the wire between the PCM (A18) and the gauge assembly- An intermittent shon in the wire betlveen the PCM (D4) and the MAP sensor- An intermiftent short in the wire between the PCM {D10) and the TP sensor.PGM-Fl main relay.'See the OBD ll scan tool or Honda PGM Tester user's manuals lor specilic operatinginstructions,
NOTE: An open or short in the wire between the PCM (C8) and the DLC will keep thescan tool or Honda PGM Tester lrom communicating with the PCM. You should ioterpretthis as no DTCS are indicated.
PCM CONNECTORc l3lPl scs .BRNI
lTo page 11 84)Wire sid6 of f€male terminalg
(cont'dl
11-83
The Malfunciion lndicator Lamo{MlL) stavs on o. comes on afteltwo seconds,
Check the Oiegnosiic TroubleCode (DTC):
1. Connect an OBD ll scan toolor Honda PGM Tester.2. Turn the ignition switch ON 1lli.3. Read the DTC with the scantool or Honda PGII Tester.
Go to troubleshooting procedures(s€€ page 11501.Are any DTCIs) indicated?
Ch6ck lh6 DTC by MIL indication:1. Turn the ignition switch OFF.2. Connect the SCS service con-nector to the service checkconnector.3. Turn the ignition switch ON (ll).
- Repair opon or short in wi.6between the PCM (C8) andData Link Connector.- Go to troubloshooting proce-
dur€s {3ee page 11-601.
Does the MIL indicate any DTc?
Try to start the engine.
Does the engine start?
Check tor a short in the wire{SCS line):1. Turn the ignition switch OFFand turn the ignition switchoN flt).2. Measure voltage between thePCM connector terminal C7and body ground.
Repair short to body ground inthe wire between PCM lCTl andservice check connector.ls there approx. 5 V?
(To page 1'l-84)
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Powertrain Control Module (PCM) -'97 Model (cont'dl
(From page 11 83)
Check for a short in the wire (MlL
line):1. Turn the ignition switch OFF.2. Disconnect the PCM connectorA {32P).3. Turn the ignition switch ON (ll).
Repair short to body ground inthe wire between the PCM {418}and MlL.ls the MIL ON?
Substitute a known-good PCMand recheck. lf symptom/indica-tion goes away. replace the origi-nal PCM.
Inspect Fl E/M (15 A) fuse in theundeFhood fuse/relay box.
- Reoair shod in the wirebetween Fl E/M {15 A} fuseand PGM-FI main relav.- Replace FIE/M 115 A)fuse.
Inspect No. 13 FUEL PUMP (15 Aifuse in the underdash fuse/relay
- Repair short in lh€ wirebolween No. 13 FUEL PUMP
115 A) Iuse and PGM-FI main
- Replace No. 13 FUEL PUMP
115 A) fuse.
Check loJ a short in a sensor:1. Turn the ignit;on switch ON (ll).
2. Disconnect the 3P connectorof each sensor one at time:. MAP sensor
(To page 11-85)
11-84
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PGM-FI System
Tho Maltunction Indicator Lamo(MlL) n6Yor como3 on leven lortwo laconds) rft6r tho ignhion isturnod ON {lll.
Turn th6 ignition switch ON (ll).
- Repair lhort or opcn in thowire between the No. 25METER 17.5 Al fu3e snd thegauge assembly.- Repl.co the No. 25 METER17.5 Al fus€.
ls the low oil pressure light on?
Try to start the engine.
Chock for an opsn in th€ wiro orbulb {MlL line,:1. Turn the ignition switch OFF.2. Connect the ECM/PCM con-nector terminal A18 to bodyground with a iumper wire.3. Turn the ignition switch ON (ll).
Rep.ir open in the wi.osbotween the ECM/FCM lA18land the gaugo rasombly.Roplece the MIL bulb.
ls th6 MIL on?
Substitute a known-good ECM/PCM and rochock. lf rymptom/indication goes eway, replacetho o gind ECM/PCM.
Turn the ignition switch OFF.Inspect the Fl E/M 115 A) tusein the undeFhood fuse/relaybox.
- Repair short in the wirebetween lhe Fl E/M (15 AlfusG and the PGM-Fl m.in.slay.- Roplsce th€ Fl E/M (15 Alfu3€.
Inspect the No. 13 FUEL PUMP(15 A) fuse in the under-dashfuse/relay box.
- Repair short in th6 wirebetween tho No. 13 FUELPUMP 115 A) luse and thePGM-FI main .elay.- ReDlace tho No. 13 FUELPUMP 115 Al tuse.
Engine Gontrol Module/Powertrain Control Module (ECM/PCM) -'98 - 00 Models
NOTE:. lf this symptom is intermittent, check tor:- A loose Fl E/M {15 A) fuse in the under-hood fuse/relay box- A loose No. 25 METER {7.5 A) fuse in the under-dash fuse/relay box- A loose No. 13 FUEL PUMP (15 Alfuse in the underdash fuse/rolay box- An intermiftent short in the wire between the ECM/PCM (A18) and the gauge assem-
- An int€rmiftent short in the wire between the ECM/PCM (C19) and the MAP sensor- An intermiftent short in the wire between rhe ECM/PCM (C28), the TP sensor, theEGR valve lift sensor and/or {uel tank Dressure sensor- A laulty PGM-FI main relay
ECM/PCM CONNECTOR A (32P}
Wire side of female terminals
(To page 11-871
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