engine ACURA NSX 1997 Service Owner's Manual

Emission Control System

Evaporative Emission (EVAP) Controls

Description

The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The

system consists of the following components:

A. Evaporative Emission (EVAP) Control Canister

An EVAP control canister is used for the temporary storage of fuel vapor until the fuel vapor can be purged from the

EVAP control canister into the engine and burned.

B. Vapor Purge Control System

EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a port

on the throttle body. The purging vacuum is controlled by the EVAP purge control solenoid valve.

C. Fuel Tank Vapor Control System

When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and

regulates the flow of fuel vapor to the EVAP control canister.

D. Onboard Refueling Vapor Recovery (ORVR) System

During refueling, the ORVR (Onboard Refueling Vapor Recovery) vent shut valve opens with the pressure in the fuel

tank, and feeds the fuel vapor to the EVAP control canister.ProCarManuals.com

Pulsed Secondary Air Injection System Description

The air pump system is designed to advance the activation of the catalyst and to reduce the hydrocarbons (HC), carbon

monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas.

The system operates after the engine starts under the following conditions:

• The engine coolant temperature is between 0°C and 70°C (32°F and 158°F).

• The difference in engine coolant temperature is more than 20°C (36°F) between the time when the engine is started and

when the engine is stopped in the previous driving cycle.

AIR CONTROL

SOLENOID VALVE

AIR CONTROL

VALVE

WHT

AIR PUMP

RELAY
From

No. 5 BACK-UP LIGHTS

ALTERNATOR

TURN SIGNALS

(15 A) FUSE

From

AIR PUMP

(60 A) FUSE

AIR CONTROL VALVE

VACUUM TANK

AIR CONTROL VALVE

CHECK VALVE

When the engine is started, the air pump runs and sends fresh air to the air control valve. The air control valve allows the

fresh air to flow to the exhaust ports when its diaphragm is pulled by engine vacuum. It gets engine vacuum from the air

control solenoid, which is activated by the ECM. Once the fresh air flows into the exhaust ports near the exhaust valves, it

reacts with the exhaust gases, raising exhaust gas temperatures. This promotes faster warm-up of the catalytic converter.

The system operates for a maximum of 60 seconds, but the running time shortens in relation to the engine coolant tem-

perature and the intake air temperature. When the system is not operating, the air control solenoid and the air control

valve are closed to prevent exhaust gases from entering the system.
AIR PUMP

ELECTRICAL

CURRENT

SENSORProCarManuals.com

Troubleshooting Precaution s
ABS Indicato r
1. I f th e syste m is OK , th e AB S indicato r come s o n fo r tw o second s (initia l tur n on ) afte r turnin g th e ignitio n switc h O N (II) ,
the n th e AB S indicato r goe s off . Afte r tha t time , th e AB S indicato r come s o n agai n afte r startin g th e engine , the n th e
AB S indicato r goe s of f tw o second s afte r th e ignitio n switc h retur n t o O N (II) . Thi s occur s becaus e th e AB S contro l uni t
activate s b y th e powe r sourc e circui t tha t i s connecte d onl y whe n th e ignitio n switc h is O N (II) .
2 . I f a proble m occurs , th e Centra l Processin g Uni t (CPU ) diagnose s th e proble m are a an d th e proble m condition , the n th e
CP U memorize s th e Diagnosti c Troubl e Cod e (DTC ) an d turn s o n th e AB S indicator . I f th e syste m is OK , th e AB S indicato r
doe s no t com e o n excep t whe n th e ignitio n switc h is initiall y turne d on .
3 . I f th e proble m is detecte d intermittentl y o r continuously , th e AB S indicato r indicatio n patter n i s differen t a s describe d
below .
• DT C 61 o r 62 :
The AB S indicato r come s o n whe n a proble m is detecte d in ever y tim e th e syste m is activated , an d th e AB S indicato r
goe s of f whe n th e syste m return s t o normal .
• DT C 11 , 13 , 15 , 17 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 54 , 7 1 o r 81 :
The AB S indicato r come s o n whe n a proble m is detecte d in ever y tim e th e syste m is activated , an d th e AB S indicato r
continue s o n unti l th e ignitio n switc h is turne d OF F regardles s o f th e syste m return s t o norma l o r not .
• DT C 12 , 14 , 16 , 18 , 21 , 22 , 23 , 24 , 41 , 42 , 43 , 44 , 51 , 5 2 o r 53 :
The AB S indicato r come s o n whe n a proble m is detected , an d th e AB S indicato r continue s o n unti l th e ignitio n switc h
i s turne d OFF . Th e AB S indicato r goe s of f whe n th e syste m is activate d th e nex t time .
4 . Th e AB S indicato r come s o n whe n th e AB S contro l uni t detect s a proble m in th e system . However , eve n thoug h th e
syste m is operatin g properly , th e AB S indicato r wil l com e on , unde r th e followin g conditions . T o determin e th e actua l
caus e o f problem , questio n th e custome r abou t th e problem , takin g thes e condition s int o consideration .
• Onl y driv e whee l (o r wheels ) rotat e
• On e driv e whee l i s stuc k
• Vehicl e spi n
• AB S continuou s operat e fo r a lon g tim e
• Signa l disturbanc e
Diagnosti c Troubl e Cod e (DTC )
1 . I f a proble m occur s i n th e system , th e Centra l Processin g Uni t (CPU ) diagnose s th e proble m are a an d th e proble m
condition , the n th e CP U memorize s th e Diagnosti c Troubl e Cod e (DTC ) int o th e EEPRO M (non-volatil e memory) .
2 . Th e DT C clearin g i s possibl e onl y whe n performin g th e specifie d procedures , an d th e DT C is no t cleare d unde r th e
followin g conditions .
• Turnin g th e ignitio n switc h of f o r disconnectin g th e batter y termina l
• Th e syste m return s t o norma l
3 . Th e memor y ca n hol d an y numbe r o f DTCs . However , whe n th e sam e DT C is detecte d mor e tha n once , th e late r on e is
writte n ove r th e previou s one . Therefore , whe n th e sam e proble m is detecte d repeatedly , i t i s memorize d a s on e DTC .
4 . Th e DTC s ar e indicate d in th e orde r o f ascendin g number , no t i n th e orde r the y occur .
5 . Perfor m th e specifie d procedure s t o indicat e th e DTCs .
Self-diagnosi s
1. Self-diagnosi s can b e classified into tw o categories .
• Initia l diagnosis : Performe d righ t afte r th e engin e start s an d unti l th e AB S indicato r goe s off .
• Regula r diagnosis : Performe d righ t afte r th e initia l diagnosi s an d unti l th e ignitio n switc h i s turne d off .
2 . Whe n a proble m is detecte d b y self-diagnosis , th e syste m
• Turn s th e AB S indicato r O N
• Memorize s th e DT C
• Stop s AB S contro l
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ABS Modulator-Contro l Uni t
Removal/Installatio n
NOTE:
• D o no t spil l brak e flui d o n th e vehicle ; i t ma y damag e th e paint ;
i f brak e flui d doe s contac t th e paint , was h i t of f immediatel y
wit h water .
• Tak e car e no t t o damag e o r defor m th e brak e line s durin g
remova l an d installation .
• T o preven t th e brak e flui d fro m flowing , plu g an d cove r th e
hos e end s an d joint s wit h a sho p towe l o r equivalen t material .
Removal
1. Pul l th e loc k o f th e AB S contro l uni t 25 P connecto r up , the n dis -
connec t th e connector .
2 . Disconnec t th e si x brak e pipes .
3 . Remov e th e tw o 6 m m nuts .
4 . Remov e th e AB S modulator-contro l unit .
Installatio n
1. Instal l th e AB S modulator-contro l uni t s o alignin g th e fla t sec -
tio n o f th e mountin g bol t an d sli t o f th e bracket , the n tighte n th e
tw o 6 m m nuts .
2 . Alig n th e connectin g surfac e o f th e AB S contro l uni t 25 P con -
nector .
3. Pus h th e loc k o f th e AB S contro l uni t 25 P connecto r i n unti l yo u
hea r th e sound , the n connec t th e connector .
4 . Blee d th e brak e system , startin g wit h th e fron t wheels .
5 . Star t th e engine , an d chec k tha t th e AB S indicato r goe s off .
6 . Test-driv e th e vehicle , an d chec k tha t th e AB S indicato r doe s
no t com e on .
LOC K
ABS CONTRO L UNI T 25 P CONNECTO R
To left-fron t
To right-rear
To left-rea r
To right-fron t
ABS MODULATOR-CONTRO L UNIT
RUBBE R MOUN T
MOUNTIN G BOL T
FLA T SECTIO N
6 m m NU T9.8 N- m (1. 0 kgf-m , 7. 2 Ibf-ft )
8 m m BOL T
22 N-m (2.2 kgf-m, 16 Ibf-ft) ABS CONTRO L UNI T 25 P CONNECTO R
SLI
T
BRACKE T
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Engine Compartment

AIR PUMP RELAY

Wire colors: YEL/BLK,

BLK,
WHT and BLKProCarManuals.com

Gauge Assembl y
Gauge/Termina l Locatio n Inde x
SRS component s ar e locate d in thi s area . Revie w th e SR S componen t locations , precautions , an d procedure s in th e SR S
sectio n 24 befor e performin g repair s o r service .
SPEEDOMETER :Indicates 6 0 mp h [60km/h ] a t 1.02 6 [637 ]rpm o f th e vehicl e spee d senso r (VSS) .
TACHOMETER :
Indicates 10 0 rp m a t 30 0 pulse s pe r minut eof th e ignite r unit .
COOLAN T TEMPERATUR E GAUG E
• Test , pag e 23-3 4
VOLTAG E METE R
ENGINE OI L PRESSUR E
GAUGE
A/T GEA R POSITIO N
INDICATO R SYSTE M
SAFET
Y INDICATO R SYSTE M
FUE
L GAUG E
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Emission Group Identification

Example:
Engine and Evaporative Families

50ST (50 States):

THIS VEHICLE CONFORMS TO U. S. ERA NLEV REGULA-

TIONS APPLICABLE TO 2001 MODEL YEAR NEW LEV

PASSENGER CARS AND CALIFORNIA REGULATIONS

APPLICABLE TO 2001 MODEL YEAR NEW LEV PASSEN-

GER CARS.

CANADIAN TIER 1

THIS VEHICLE CONFORMS TO CANADIAN TIER 1 STAN-

DARDS FOR 2001 MODEL YEAR NEW PASSENGER

CARS.ProCarManuals.com

CAUTION: (if roof maintenance is required)

Be careful not ot bend the edge of the roof opening.

The roof is made of aluminum alloy. Take care not to dent or scratch the roof. If there is a minor dent or scratch on the roof, repair
the roof with putty (refer to the body repair manual).

When replacing the component parts of the roof, place the roof on an appropriate pad to prevent damage.
NOTE:

Have an assistant help remove the roof.

When the roof is stored on the engine cover, lock the roof cover securely.

When installing the roof, secure it by turning both roof side lock handles. Make sure they are locked securely.
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Chassis and Paint Codes

Vehicle Identification Number

Transmission Number

Paint Code

Vehicle Identification Number

and Federal Motor Vehicle

Safety Standard Certification

Vehicle Identification Number and Canadian

Motor Vehicle Safety Standard Certification

Engine Number

Paint CodeProCarManuals.com

Engine Block — Section 7
Engine Lubricatio n — Sectio n 8
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