1995 ACURA TL ECO mode

According t o stat e an d federa l regulations , failur e t o perfor m maintenanc e o n th e item s marke d wit h a n asteris k (* ) wil l no t voi d customer' s emissio n war -
ranties . However , Acur a recommend s tha t al l maintenanc e service s b e performe d a t th e recommende d tim e o r mileag e perio d t o ensur e long-ter m reliability .
Sever e Drivin g Conditions :
• Drivin g les s tha n 5 mile s ( 8 km ) pe r tri p or , i n freezin g temperatures , drivin g les s tha n 1 0 mile s (1 6 km ) pe r trip .
• Drivin g i n extremel y ho t [ove r 90° F (32°C) ] conditions .
• Extensiv e idlin g o r lon g period s o f stop-and-g o driving .
• Traile r towing , drivin g wit h a car-to p carrier , o r drivin g i n mountainou s conditions .
• Drivin g o n muddy , dusty , o r de-ice d roads .
NOTE: I f th e vehicl e is drive n OCCASIONALL Y unde r a "severe " condition , you shoul d follo w th e Norma l Condition s Maintenanc e Schedul e fo r 199 8 Mode l o n
page s 4-1 2 an d 4-13 .
17-2 2
16-3
19-3 0
10-5, 14-105 ,15-4, 19- 7
10- 3
9-5
11-11 8
23-16 8
ProCarManuals.com

System Descriptio n
Vacuum Connection s
'95 - 9 6 models :
EVAPORATIV EEMISSION(EVAP)PURGE CONTRO L
SOLENOI D VALV E
CONTRO L BO X
pag e 11- 9
INTAK E AI R BYPAS S (IAB )
VACUU M TAN KTo EVAPORATIV E
EMISSIO N (EVAP )
TW O WA Y VALV E
FRON T O F
VEHICL E
INTAK E AI R BYPAS S (IAB )
CONTRO L SOLENOI D VALV E INTAK
E AI R BYPAS S
(IAB ) CHEC K VALV E
WATERVALVECONTRO L
DIAPHRAG MEVAPORATIV
E EMISSIO N
(EVAP ) PURG E FLO WSWITC H
EXHAUS T GA S RECIRCULATIO N
(EGR ) VALV E an d LIF T SENSO R
INTAK E AI R
BYPAS S (IAB )
CONTRO L DIAPHRAG M
VALV E
FUELPRESSUR EREGULATO R
To ENGIN E
MOUN T CONTRO L
SOLENOI D VALV E EVAPORATIV
E
EMISSION(EVAP)CONTRO LCANISTER
ProCarManuals.com

System Descriptio n
Vacuum Connection s (cont'd )
'97 - 9 8 models :
EVAPORATIV EEMISSION(EVAP) CONTRO L
CANISTE R VEN T
SHU T VALV E
EVAPORATIV E EMISSIO N
(EVAP ) CONTRO L
CANISTE R
FRON T O F
VEHICL E
INTAKE AI RBYPAS S (IAB )
CONTRO L SOLENOI D VALV E
EXHAUS T GA S RECIRCULATIO N
(EGR ) VALV E an d LIF T SENSO R
FUE L
PRESSUR EREGULATO R INTAK
E AI R
BYPAS S (IAB )
CONTRO L DIAPHRAG M VALV E
CONTRO L BO X
pag e 11- 9
EVAPORATIV E EMISSIO N
(EVAP)PURGE CONTRO L
SOLENOI D VALV E
INTAK E AI R
BYPAS S (IAB )
CHEC K VALV E
WATE RVALVECONTRO L
DIAPHRAG M
T o EVAPORATIV E
EMISSIO N (EVAP )
TW O WA Y VALV E INTAK
E
AIRBYPAS S (IAB )VACUU MTANK
ProCarManuals.com

System Description

Vacuum Connections (cont'd)

'95 - 96 models:

PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S)

SECONDARY HEATED OXYGEN SENSOR (SECONDARY

HO2S)

MASS AIR FLOW (MAP) SENSOR

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

INTAKE AIR TEMPERATURE (IAT) SENSOR

FRONT KNOCK SENSOR (FKS)

REAR KNOCK SENSOR (RKS)

IDLE AIR CONTROL (IAC) VALVE

FAST IDLE THERMO VALVE

IDLE ADJUSTING SCREW

THROTTLE BODY (TB)

FUEL INJECTOR

FUEL FILTER

FUEL PRESSURE REGULATOR

FUEL PULSATION DAMPER

FUEL PUMP (FP)

FUEL TANK

FUEL TANK EVAPORATIVE EMISSION (EVAP) VALVE

AIR CLEANER

RESONATOR

CRANKSHAFT SPEED FLUCTUATION (CKF) SENSOR

INTAKE AIR BYPASS (IAB) CHECK VALVE
INTAKE AIR BYPASS (IAB) VACUUM TANK

INTAKE AIR BYPASS (IAB) CONTROL SOLENOID VALVE

INTAKE AIR BYPASS (IAB) CONTROL DIAPHRAGM

EXHAUST GAS RECIRCULATION (EGR) VACUUM CONTROL

VALVE

EXHAUST GAS RECIRCULATION (EGR) CONTROL

SOLENOID VALVE

EXHAUST GAS RECIRCULATION (EGR) VALVE

EXHAUST GAS RECIRCULATION (EGR) VALVE LIFT

SENSOR

POSITIVE CRANKCASE VENTILATION (PCV) VALVE

EVAPORATIVE EMISSION (EVAP) PURGE CONTROL

SOLENOID VALVE

EVAPORATIVE EMISSION (EVAP) PURGE FLOW SWITCH

EVAPORATIVE EMISSION (EVAP) CONTROL CANISTER

EVAPORATIVE EMISSION (EVAP) PURGE CONTROL

DIAPHRAGM VALVE

EVAPORATIVE EMISSION (EVAP) TWO WAY VALVE

WARM UP THREE WAY CATALYTIC CONVERTER (WU TWC)

THREE WAY CATALYTIC CONVERTER (TWC)

WATER VALVE CONTROL SOLENOID VALVE

WATER VALVE CONTROL DIAPHRAGM

WATER VALVE CHECK VALVEProCarManuals.com

'97 - 98 models:

Vacuum hose No.

PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S)

SECONDARY HEATED OXYGEN SENSOR (SECONDARY

HO2S)

MASS AIR FLOW (MAP) SENSOR

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

INTAKE AIR TEMPERATURE (IAT) SENSOR

FRONT KNOCK SENSOR (FKS)

REAR KNOCK SENSOR (RKS)

IDLE AIR CONTROL (IAC) VALVE

FAST IDLE THERMO VALVE

IDLE ADJUSTING SCREW

THROTTLE BODY (TB)

FUEL INJECTOR

FUEL FILTER

FUEL PRESSURE REGULATOR

FUEL PULSATION DAMPER

FUEL PUMP (FP)

FUEL TANK

FUEL TANK EVAPORATIVE EMISSION (EVAP) VALVE

AIR CLEANER

RESONATOR

CRANKSHAFT SPEED FLUCTUATION (CKF) SENSOR

INTAKE AIR BYPASS (IAB) CHECK VALVE

INTAKE AIR BYPASS (IAB) VACUUM TANK

INTAKE AIR BYPASS (IAB) CONTROL SOLENOID VALVE
INTAKE AIR BYPASS (IAB) CONTROL DIAPHRAGM

EXHAUST GAS RECIRCULATION (EGR) VACUUM CONTROL

VALVE

EXHAUST GAS RECIRCULATION (EGR) CONTROL

SOLENOID VALVE

EXHAUST GAS RECIRCULATION (EGR) VALVE

EXHAUST GAS RECIRCULATION (EGR) VALVE LIFT

SENSOR

POSITIVE CRANKCASE VENTILATION (PCV) VALVE

EVAPORATIVE EMISSION (EVAP) PURGE CONTROL

SOLENOID VALVE

EVAPORATIVE EMISSION (EVAP) CONTROL CANISTER

EVAPORATIVE EMISSION (EVAP) CONTROL CANISTER

VENT SHUT VALVE

EVAPORATIVE EMISSION (EVAP) THREE WAY VALVE

EVAPORATIVE EMISSION (EVAP) TWO WAY VALVE

EVAPORATIVE EMISSION (EVAP) BYPASS SOLENOID

VALVE

FUEL TANK PRESSURE SENSOR

WARM UP THREE WAY CATALYTIC CONVERTER (WU TWC)

THREE WAY CATALYTIC CONVERTER (TWC)

WATER VALVE CONTROL SOLENOID VALVE

WATER VALVE CONTROL DIAPHRAGM

WATER VALVE CHECK VALVEProCarManuals.com

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

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 .
ProCarManuals.com

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 )
ProCarManuals.com