1995 ACURA TL air condition

SERVICE INFORMATIO N(1995-1996,1998 )VEHICLE EMISSIO N CONTRO LINFORMATION/VACUU MHOSE ROUTIN G DIAGRA M(1997: KA )VEHICL E EMISSIO N CONTRO LINFORMATIO N (1997 : KC )
COOLAN TINFORMATIO N(1995-1996)VACUUM HOS EROUTIN G DIAGRA M(1997 -1998 : KC)
COOLAN TINFORMATIO N (199 7 -1998 )
AIR CONDITIONIN G
INFORMATIO N
(1995-1997 )
BATTERYCAUTION(1995 -1998 )
AIR CLEANER ,RECOMMENDE DENGINE OI Land FILTER , SPAR KPLUG SERVIC E(1995-1998 )
TIRE INFORMATIO N(1995 - 1996 )TIRE INFORMATIO N(1997 -1998 )
RADIATO R CA PCAUTIO N
(199 5 -1998 )
NOTE: Refe r t o page 1-9a of th e '9 6-9 8 Acura 3.2TL Servic e Manual supplement forfor the differences on this page for the 3.2TL.
ProCarManuals.com

Data
Description

Operating Value
Freeze Data

HO2S

Feedback

Loop Status
Loop status is indicated as "open" or "closed".

Closed: Based on the HO2S output, the ECM deter-

mines the air/fuel ratio and controls the amount of

injected fuel.

Open: Ignoring HO2S output, the ECM refers to signals

from the TP, MAF, and ECT sensors to control the

amount of injected fuel.
At idle speed: closed

Short Term

Fuel Trim
The air/fuel ratio correction coefficient for correcting

the amount of injected fuel when H02S feedback is in

the closed loop status. When the signal from the H02S

is weak, short term fuel trim gets higher, and the ECM

increases the amount of injected fuel. The air/fuel ratio

gradually gets richer, causing a higher HO2S output.

Consequently, the short term fuel trim is lowered, and

the ECM reduces the amount of injected fuel. This

cycle keeps the air/fuel ratio close to the stoichiometric

ratio when in closed loop status.
±20%

Long Term

Fuel Trim
Long term fuel trim is computed from short term fuel

trim and indicates changes occurring in the fuel supply

system over a long period.

If long term fuel trim is higher than 1.00, the amount of

injected fuel must be increased. If it is lower than 1.00,

the amount of injected fuel must be reduced.
±20%

Intake Air

Temperature

(IAT)
The IAT sensor converts intake air temperature into

voltage and signals the ECM. When intake air tempera-

ture is low, the internal resistance of the sensor

increases, and the voltage signal is higher.
With cold engine:

Same as ambient temper-

ature and ECT

Throttle

Position
Based on the accelerator pedal position, the opening

angle of the throttle valve is indicated.
At idle speed:

approx. 10%

Ignition

Timing
Ignition timing is the ignition advance angle set by the

ECM. The ECM matches ignition timing to the driving

conditions.
At idle speed: 15° ±2°

BTDC with the SCS service

connector connected.

Calculated

Load Value

(CLV)
CLV is the engine load calculated from the MAF data.
At idle speed:

14-27%

At 2,500 rpm with no load:

13-26%ProCarManuals.com

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

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

Idle Contro l Syste m
Air Conditionin g Signa l
This signal s th e EC M whe n ther e is a deman d fo r coolin g fro m th e ai r conditionin g system .
Inspectio n o f Ai r Conditionin gSignal.ECM CONNECTOR S
A (26P)
Chec k fo r a shor t i n th e wir e
(AC S line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e A/ C pressur e
switc h connector .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n
EC M connecto r terminal s B 3
an d A26 .
Wire sid e o f femal e terminal s
I s ther e batter y voltage ?
Chec k fo r a n ope n i n th e wir e
(ACC line) :1. Tur n th e ignitio n switc h OFF .
2 . Reconnec t th e A/ C pressur e
switc h connector.
3 . Tur n th e ignitio n switc h O N (II) .
4 . Momentaril y connec t EC M
connecto r terminal s A 8 an d
A2 6 wit h a jumpe r wire sever -
a l times .
(T o pag e 11-109 ) Chec
k fo r a shor t i n th e wir e (AC S
line):1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e EC M connec -
tor B (16P) .3. Chec k fo r continuit y betwee n
bod y groun d an d EC M con -
necto r termina l B3 . EC
M CONNECTO R B (16P )
Wir e sid e o f femal e terminal s
I s ther e continuity ? Repai
r shor t i n th e wir e betwee n
the EC M (B3 ) an d th e A/ C pres -sure switch .
Substitut e a known-goo d EC M
an d recheck . I f prescribe d volt -
ag e is no w available , replac e
th e origina l ECM .
Se e th e ai r conditione r inspec -
tio n (se e sectio n 22 ).
ECM CONNECTO R A (26P )
Wir e sid e o f femal e
terminal s JUMPE
R
WIRE
B (16P )
ProCarManuals.com

Intake Air System

Air Cleaner (ACL)

ACL Element Replacement

NOTE: When removing the ACL housing cover, do not disconnect the hose and MAF sensor connector.

ACL HOUSING

COVER

MAF SENSOR

ACL

HOUSING
ACL ELEMENT

Normal conditions:

Replace air cleaner element every

30,000 miles (48,000 km) or 24

months whichever comes first.

Severe conditions:

Clean air cleaner element every

15,000 miles (24,000 km) or 12

months and replace every 30,000

miles (48,000 km) or 24 months

whichever comes first.ProCarManuals.com

12. Mov e th e shif t for k towar d th e torqu e converte r sid e
a s shown .
SHIFT FOR K
13. Mak e sur e tha t th e deten t leve r i s i n th e position .
NOTE: I f th e deten t leve r i s no t i n th e position ,
th e lowe r valv e bod y assembl y canno t b e removed .
14 . Remov e th e si x bolt s securin g th e lowe r valv e bod y
assembl y a s shown , the n remov e th e lowe r valv e
bod y assembly .
6 x 5 0 m m
6 x 2 5 m m
6 x 50 m m6 x 40 m m
15. Clea n th e inle t openin g o f th e AT F straine r thoroughl y
wit h compresse d air , the n chec k tha t i t i s i n goo d
condition , an d th e inle t openin g i s no t clogged .
INLET OPENIN G
ATF STRAINE R
16. Replac e th e AT F straine r i f i t i s clogge d o r damaged .
NOTE : Th e AT F straine r ca n b e reuse d i f i t i s no t
clogged .
ProCarManuals.com