Page 873 of 1771
Troubleshooting
Diagnostic Troubl e Cod e (DTC ) Char t (cont'd )
Page
11-88
11-88
11-148
11-146
11-165
11-1 56
11-161 11-163 11-90
11-103
Section 14
*1 : '9 5 -9 6 model s
*2:'97-9 8 model s
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Page
11-6 0
11-61
11-9 1
11-9 2
11-9 2
11-71
11-7 2
11-93
11-9 4
11-95
11-9 5
11-9 7
11-88
11-88
*2: '9 7 - 9 8 model s
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Page 875 of 1771
Troubleshooting
Diagnostic Troubl e Cod e (DTC ) Char t (cont'd )
Page
11-88
11- 88
11-158
11-149 11-15211-105 11- 98
11-100 11-10011-100
11-100
Section 14
*1 : '9 5 -9 6 model s
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Page 876 of 1771

How to Read Flowcharts
A flowchart is designed to be used from start to final repair. It's like a map showing you the shortest distance. But beware:
If you go off the "map" anywhere but a "stop" symbol, you can easily get lost.
Describes the conditions or situation to start a troubleshooting flowchart.
Asks you to do something; perform a test, set up a condition etc.
Asks you about the result of an action, then sends you in the appropriate troubleshooting direction.
The end of a series of actions and decisions, describes a final repair action and sometimes directs you to
an earlier part of the flowchart to confirm your repair.
NOTE:
The term "Intermittent Failure" is used in these charts. It simply means a system may have had a failure, but it checks
out OK at this time. If the Malfunction Indicator Lamp (MIL) on the dash does not come on, check for poor connections
or loose wires at all connectors related to the circuit that you are troubleshooting (see illustration below).
Most of the troubleshooting flowcharts have you reset the Engine Control Module (ECM) and try to duplicate the
Diagnostic Trouble Code (DTC). If the problem is intermittent and you can't duplicate the code, do not continue though
the flowchart. To do so will only result in confusion and, possibly, a needlessly replaced ECM.
"Open" and "Short" are common electrical terms. An open is a break in a wire or at a connection. A short is an acci-
dental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't
work at all. In complex electronics (like ECM's), this can sometimes mean something works, but not the way it's sup-
posed to.
TIGHT
LOOSEProCarManuals.com
Page 877 of 1771

PGM-FI System
System Description
INPUTS
ENGINE CONTROL MODULE (ECM)
OUTPUTS
Fuel Injectors
PGM-FI Main Relay (Fuel Pump)
MIL
IAC Valve
A/C Compressor Clutch Relay
Radiator Fan Relay
Condenser Fan Relay
ALT
ICM
EVAP Purge Control Solenoid
Valve
Primary HO2S Heater
Secondary H02S Heater
EGR Control Solenoid Valve
IAB Control Solenoid Valve
EVAP Bypass Solenoid Valve*2
EVAP Control Canister Vent Shut
Valve*2
*1: '95-96 models
*2: '97 - 98 models
PGM-FI System
The PGM-FI system on this model is a sequential multiport fuel injection system.
Fuel injector Timing and Duration
The ECM contains memories for the basic discharge durations at various engine speeds and manifold air flow rates. 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.
Idle Air Control
Idle Air Control Valve (IAC Valve)
When the engine is cold, the A/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 controls current to the IAC Valve to maintain the correct idle speed.
Ignition Timing Control
• The ECM contains memories for basic ignition timing at various engine speeds and manifold air flow rates. Ignition
timing is also adjusted for engine coolant temperature.
• A knock control system is also used. When detonation is detected by a knock sensor (KS), the ignition timing is retarded.
Other Control Functions
1. Starting Control
When the engine is started, the ECM provides a rich mixture by increasing fuel injector duration.
2. Fuel Pump Control
• When the ignition switch is initially turned on, the ECM supplies 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 supplies ground to the PGM-FI main relay that supplies current to the fuel pump.
• When the engine is not running and the ignition is on, the ECM cuts ground to the PGM-FI main relay which cuts
current to the fuel pump.
3. Fuel Cut-off Control
• During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at
speeds over 1,250 rpm.
• Fuel cut-off action also takes place when engine speed exceeds 7,100 rpm, regardless of the position of the throttle
valve, to protect the engine from over-revving.
CKP/TDC/CYP Sensor
CKF Sensor
MAF Sensor
ECT Sensor
IAT Sensor
TP Sensor
EGR Valve Lift Sensor
Primary HO2S
Secondary H02S
VSS
BARO Sensor
ELD
Front KS
Rear KS
Starter Signal
ALT FR Signal
Air Conditioning Signal
A/T Gear Position Signal
Battery Voltage (IGN.1)
Brake Switch Signal
PSP Switch Signal
EVAP Purge Flow Switch*1
Fuel Tank Pressure Sensor*2ProCarManuals.com
Page 878 of 1771

4. A/ C Compresso r Clutc h Rela y
When th e EC M receive s a deman d fo r coolin g fro m th e ai r conditionin g system , i t delay s th e compresso r fro m bein g
energized , an d enriche s th e mixtur e to assur e smoot h transitio n to th e A/ C mode .
5 . Evaporativ e Emissio n (EVAP ) Purg e Contro l Solenoi d Valv e
Whe n th e engin e coolan t temperatur e i s belo w 167° F (75°C ) ('9 7 - 9 8 models : 158° F (70°C) , th e EC M control s th e
EVA P purg e contro l solenoi d valv e whic h cut s vacuu m to th e EVA P purg e contro l caniste r diaphragm .
6 . Intak e Ai r Bypas s (IAB ) Contro l Solenoi d Valv e
Whe n th e engin e spee d i s belo w 4,80 0 rpm , th e IA B contro l solenoi d valv e i s activate d b y a signa l fro m th e ECM ,
intak e ai r flow s throug h th e smalle r chamber , the n hig h torqu e i s delivered. At speed s highe r tha n 4,80 0 rpm , th e
solenoi d valv e i s deactivate d b y th e ECM , an d intak e ai r flow s throug h th e large r chambe r i n orde r t o reduc e th e
resistanc e in airflow .
7 . Exhaus t Ga s Recirculatio n (EGR ) Contro l Solenoi d Valv e
Whe n th e EG R is require d fo r contro l o f oxide s o f nitroge n (NOx ) emissions , th e EC M control s th e EG R contro l
solenoi d valv e whic h supplie s regulate d vacuu m to th e EG R valve .
8 . Alternato r Contro l
Th e syste m control s th e voltag e generate d a t th e alternato r i n accordanc e wit h th e electrica l loa d an d drivin g mode ,
whic h reduce s th e engin e loa d to improv e th e fue l economy .
ECM Fail-safe/Back-u p Function s
1. Fail-saf e Functio n
Whe n a n abnormalit y occur s in a signa l fro m a sensor , th e EC M ignore s tha t signa l an d assume s a pre-programme d
valu e fo r tha t senso r tha t allow s th e engin e to continu e to run .
2 . Back-u p Functio n
Whe n a n abnormalit y occur s in th e EC M itself , th e fue l injector s ar e controlle d b y a back-u p circui t independen t o f th e
syste m in orde r t o permi t minima l driving .
3 . Self-diagnosi s Functio n [Malfunctio n Indicato r Lam p (MIL) ]
Whe n a n abnormalit y occur s i n a signa l fro m a sensor , th e EC M supplie s groun d fo r th e MI L an d store s th e DT C in
erasable memory . Whe n th e ignitio n i s initiall y turne d on , th e EC M supplie s ground for th e MI L fo r tw o second s t o
chec k th e MI L bul b condition .
4 . Tw o Tri p Detectio n Metho d ('9 5 - 9 6 models )
T o preven t fals e indications , th e Tw o Tri p Detectio n Metho d is use d fo r th e MA F sensor , H02S , fue l metering-related ,
idl e contro l system , EC T sensor , an d EG R syste m self-diagnosti c functions . Whe n a n abnormalit y occurs , th e EC M
store s i t i n it s memory . Whe n th e sam e abnormalit y recur s afte r th e ignitio n switc h i s turne d OF F an d O N (II ) again ,
th e EC M inform s th e drive r b y lightin g th e MIL .
However ,
to eas e troubleshooting , thi s functio n is cancelle d when you shor t the servic e check connector . The MI L will
the n blin k immediatel y whe n a n abnormalit y occurs .
5 . Tw o (o r Three ) Drivin g Cycl e Detectio n Metho d ('9 5 - 9 6 models )
A "Drivin g Cycle " consist s o f startin g th e engine , beginnin g close d loo p operation , an d stoppin g th e engine . I f misfir -
in g tha t increase s emission s o r EVA P contro l syste m malfunctio n i s detecte d i n tw o consecutiv e drivin g cycles , o r
TW C deterioratio n is detecte d in thre e consecutiv e drivin g cycles , th e EC M turn s th e MI L on .
However , t o eas e troubleshooting , thi s functio n is cancelle d whe n yo u shor t th e servic e chec k connector . Th e MI L wil l
the n blin k immediatel y whe n a n abnormalit y occurs .
6 . Tw o Drivin g Cycl e Detectio n Metho d ('9 7 - 9 8 models )
T o preven t fals e indications , th e "tw o drivin g cycl e detectio n method " i s use d fo r th e H02S , fue l metering-related ,
idl e contro l system , EC T sensor , EG R system , TW C an d EVA P contro l syste m an d othe r self-diagnosti c functions .
Whe n a n abnormalit y occurs , th e EC M store s i t i n it s memory . Whe n th e sam e abnormalit y recur s afte r switc h i s
turne d OF F an d O N (II ) again , th e EC M inform s th e drive r b y turnin g o n th e MIL .
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PGM-FI System
Engine Control Module (ECM)
Is the low oil pressure light on?
Try to start the engine.
Does the engine start?
Check for an open in the wire or
bulb (MIL line):
1. Turn the ignition switch OFF.
2. Connect the ECM connector ter-
minal A7 to body ground with a
jumper wire.
3. Turn the ignition switch ON (II).
NOTE: If this symptom is intermittent, check for a loose fuse No. 1 (BACK UP
LIGHTS, METER LIGHTS, 10 A) in the under-dash fuse/relay box, a poor con-
nection at ECM terminal A7, or an intermittent open in the GRN/RED wire
between the ECM (A7) and the gauge assembly.
Is the MIL on?
Substitute a known-good ECM
and recheck. If symptom/indica-
tion goes away, replace the origi-
nal
ECM.
— Repair short in the wire
between NO. 1 (BACK-UP
LIGHTS, METER LIGHTS) (10
A) fuse and gauge assembly.
— Replace No. 1 (BACK-UP
LIGHTS, METER LIGHTS) (10 A)
fuse.
Check for an open in the wires
(PG1, PG2 lines):
1. Turn the ignition switch ON (II).
2. Measure voltage between
body ground and ECM con-
nector terminals A12 and A25
individually.
Is there less than 1.0 V?
Repair open in the wires
between ECM (A7) and gauge
assembly.
Replace the MIL bulb.
ECM CONNECTOR A (26P)
Wire side of female terminals
Repair open in the wire(s)
between ECM and G101 (located
at left side of engine) that had
more than 1.0 V.
ECM CONNECTOR A (26P)
Wire side of female terminals
The Malfunction Indicator Lamp
(MIL) never comes on (even for
two seconds) after ignition is
turned on.
Turn the ignition switch ON (II).
JUMPER WIREProCarManuals.com
Page 880 of 1771

The Malfunctio n Indicato r Lam p
(MIL ) stay s o n o r come s o n afte r
tw o seconds .
Chec k th e Diagnosti c Troubl e
Code (DTC) :1. Connec t a sca n too l o r Hond a
PG M Tester .
2 . Tur n th e ignitio n switc h O N (II) .
3 . Rea d th e DT C wit h th e sca n
too l o r Hond a PG M Tester .
NOTE:• Whe n ther e i s n o Diagnosti c Troubl e Cod e (DTC ) stored , th e MI L wil l sta y o n i f th e SC S
servic e connecto r i s connecte d an d th e ignitio n switc h is on .
• I f thi s sympto m is intermittent , chec k for :
— A loos e EC U (ECM ) (1 5 A ) fus e in th e under-hoo d fuse/rela y bo x
— A loos e No . 2 FUE L PUM P (1 5 A ) fus e in th e under-das h fuse/rela y bo x
— A n intermitten t shor t i n th e wir e betwee n th e EC M (D13 ) an d th e servic e chec k con -
necto r
— A n intermitten t ope n i n th e wir e betwee n th e EC M (D22 ) an d th e servic e chec k con -
necto r
— A n intermitten t shor t i n th e wire betwee n th e EC M (A7 ) an d th e gaug e assembl y
— A n intermitten t shor t i n th e wir e betwee n th e EC M (D10) , th e T P senso r an d th e fue l tan k
pressur e senso r ('9 7 - 9 8 models )
— A n intermitten t shor t i n th e wir e betwee n th e EC M (D21 ) an d th e EG R valv e lif t senso r
• Se e th e OB D II sca n too l o r Hond a PG M Teste r user' s manual s fo r specifi c operatin g
instructions .
Ar e an y DTC(s ) indicated ? G
o t o Diagnosti c Troubl e Cod e
(DTC ) char t (se e pag e 11-44 ).
Tr y t o star t th e engine .
Doe s th e engin e start ?
Chec k fo r a shor t i n th e wir e (SC S
line) :
1. Sto p th e engin e an d tur n th eignitio n switc h O N (II) .2. Measur e voltag e betwee n EC M
connecto r terminal s D1 3 an d
D22 .
(To pag e 11-54 ) EC
M CONNECTO R D (22P )
Wir e sid e o f femal e terminal s
I s ther e batter y voltage ? Repai
r shor t t o bod y groun d in
th e wir e betwee n EC M (D13 ) an d
servic e chec k connector .
(To pag e 11-54 )
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