1995 ACURA TL Service Repair Manual

Powertrain Contro l Modul e Dat a
B y connectin g th e OB D II sca n too l o r th e Hond a PG M Teste r t o th e 16 P dat a lin k connecto r (DLC) , variou s dat a ca n b e
retrieve d fro m th e PCM . Th e item s liste d in th e tabl e belo w confor m to th e SA E recommende d practice .
Th e Hond a PG M Teste r als o read s dat a beyon d tha t recommende d b y SAE .
Understandin g thi s dat a wil l hel p t o fin d th e cause s o f intermitten t failure s o r engin e problems .
NOTE:
The "operatin g values " give n belo w ar e approximat e value s an d ma y b e differen t dependin g o n th e environmen t an d
the individua l car .
Unles s note d otherwise , "a t idl e speed " mean s idlin g wit h th e engine completel y warme d up , transmissio n i n o r
position , an d th e A/ C an d al l accessorie s turne d off .
Dat aDescriptio nOperating Valu e
Freeze Dat a
Diagnosti c
Troubl e Cod e
(DTC )
If th e PC M detect s a problem , i t wil l stor e it a s a cod e
consistin g o f on e lette r an d fou r numbers .
Dependin g o n th e problem , a n SAE-define d cod e
(P0xxx ) o r a Honda-define d cod e (P1xxx ) wil l b e outpu t
t o th e tester . I
f n o proble m is detected ,
ther e i s n o output .
Engin e Spee d Th
e PC M compute s engin e spee d fro m th e signal s sen t
fro m th e Crankshaf t Positio n sensor .
Thi s dat a is use d fo r determinin g th e tim e an d amoun t
o f fue l injection . Nearl
y th e sam e a s
tachomete r indicatio n a t
idl e speed :
640 5 0 rp m
Vehicl e Spee d Th
e PC M convert s puls e signal s fro m th e Vehicl e
Spee d Senso r (VSS ) int o spee d data . Nearl
y th e sam e a s
speedomete r indicatio n
Manifol d
Absolut e
Pressur e (MAP )
The absolut e pressur e create d in th e intak e manifol d b y
engin e loa d an d speed . Wit
h engin e stopped :
Nearl y th e sam e a s atmo -
spheri c pressur e a t idl e
speed :
24-37 kP a (180-28 0
mmHg, 7.1-11. 0 inHg )
Engin e Coolan t
Temperatur e
(ECT)
The EC T senso r convert s coolan t temperatur e int o
voltag e an d signal s th e PCM . Th e senso r i s a thermisto r
whos e interna l resistanc e change s wit h coolan t
temperature . Th e PC M use s th e voltag e signal s fro m
th e EC T senso r t o determin e th e amoun t o f injecte d
fuel . Wit
h col d engine :
Sam e a s ambien t temper -
atur e an d IA T
Wit h engin e warme d up :
approx . 158-212° F
(70-100°C )
Heate d Oxyge n
Senso r (H02S )
(Bank 1, Sensor 1)
(Ban k 2 , Senso r 1 )
(Senso r 2 )
Th e Heate d Oxyge n Senso r detect s th e oxyge n conten t
i n th e exhaus t ga s an d send s voltag e signal s to th e
PCM . Base d o n thes e signals , th e PC M control s th e
air/fue l ratio . Whe n th e oxyge n conten t i s hig h (tha t is ,
whe n th e rati o is leane r tha n th e stoichiometri c ratio) ,
th e voltag e signa l i s lower . Whe n th e oxyge n conten t i s
lo w (tha t is , whe n th e rati o is riche r tha n th e stoichio -
metric ratio) , th e voltag e signa l i s higher .
0.0-1.2 5 V
A t idl e speed :
about 0.1-0. 9 V
O
(Senso r 1 )
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Troubleshooting
Troubleshooting Procedure s (cont'd )
DataDescriptio nOperating Valu e
Freeze Dat a
HO2 S
Feedbac k
Loop Statu s
(Bank 1 : Right )
(Bank 2 : Left )
Loop statu s i s indicate d a s "open " o r "closed" .
Closed: Based o n th e HO2 S output , th e PC M deter -
mine s th e air/fue l rati o an d control s th e amoun t o f
injecte d fuel .
Open : Ignorin g H02 S output , th e PC M refer s t o signal s
fro m th e TP , MAP , an d EC T sensor s to contro l th e
amoun t o f injecte d fuel . A
t idl e speed : close d
Shor t Ter m
Fue l Tri m
(Ban k 1 : Right )
(Bank 2 : Left )
The air/fue l rati o correctio n coefficien t fo r correctin g
th e amoun t o f injecte d fue l whe n HO2 S feedbac k is in
th e close d loo p status . Whe n th e signa l fro m th e HO2 S
i s weak , shor t ter m fue l tri m get s higher , an d th e PC M
increase s th e amoun t o f injecte d fuel . Th e air/fue l rati o
graduall y get s richer , causin g a highe r HO2 S output .
Consequently , th e shor t ter m fue l tri m is lowered , an d
th e PC M reduce s th e amoun t o f injecte d fuel . Thi s
cycl e keep s th e air/fue l rati o close to th e stoichiometri c
rati o whe n in close d loo p status .-30%-+43 %
Long Ter m
Fue l Tri m
(Ban k 1 : Right )
(Ban k 2 : Left ) Lon
g ter m fue l tri m in compute d fro m shor t ter m fue l
tri m an d indicate s change s occurrin g in th e fue l suppl y
syste m ove r a lon g period .
If lon g ter m fue l tri m is highe r tha n 1.00 , th e amoun t o f
injecte d fue l mus t b e increased . I f i t i s lowe r tha n 1.00 ,
th e amoun t o f injecte d fue l mus t b e reduced .
-19%-+25 %
Intake Ai r
Temperatur e
(IAT)
The IA T senso r convert s intak e ai r temperatur e int o
voltag e an d signal s th e PCM . Whe n intak e ai r tempera -
tur e is low , th e interna l resistanc e o f th e senso r
increases , an d th e voltag e signa l i s higher . Wit
h col d engine :
Sam e a s ambien t temper -
atur e an d EC T
Throttl e
Positio n Base
d o n th e accelerato r peda l position , th e openin g
angl e o f th e throttl e valv e is indicated . A
t idle : Approx . 10 %
At ful l throttle : Approx .
90%
Ignitio n
Timing
The ignitio n advanc e angl e is se t b y th e PCM . Th e PC M
matche s ignitio n timin g t o th e drivin g conditions .A
t idl e speed : 1 5 + 2°
BTD C wit h th e SC S servic e
connecto r connected .
Calculated
Load Valu e
(CLV )
CLV is th e engin e loa d calculate d fro m th e MA P data . At idl e speed :
15-35 %
A t 2,50 0 rp m wit h n o load :
12-30 %
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Powertrain Contro l Modul e Termina l Arrangemen t
PCM CONNECTO R A (26P )
Wire sid e o f femal e terminal s
PCM CONNECTO R A (26P )NOTE : Standar d batter y voltag e is 1 2 V .
*1 : '9 6 mode l
*2 : '9 7 - 9 8 model s
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Troubleshooting

Powertrain Control Module Terminal Arrangement (cont'd)

PCM CONNECTOR B (16P)

Wire side of female terminals

PCM CONNECTOR B (16P)

NOTE: Standard battery voltage is 12 V.ProCarManuals.com

PCM CONNECTO R C (12P )
Wir e sid e o f femal e terminal s
PCM CONNECTO R C (12P )
NOTE: Standar d batter y voltag e is 1 2 V .
*3: wit h TC S only .
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Troubleshooting

Powertrain Control Module Terminal Arrangement (cont'd)

PCM CONNECTOR D (22P)

Wire side of female terminals

PCM CONNECTOR D (22P)

NOTE: Standard battery voltage is 12 V.

*1:'96 model

*2: '97 - 98 models

*3: with TCSProCarManuals.com

PCM CONNECTO R E (26P )
Wire sid e o f femal e terminal s
PCM CONNECTO R E (26P )NOTE : Standar d batter y voltag e is 1 2 V .
*1 : '9 6 mode l
*2 : '9 7 - 9 8 model s
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Troubleshooting
Powertrain Contro l Modul e Termina l Arrangemen t (cont'd )
PCM CONNECTO R F (8P )
Wir e sid e o f mal e terminal s
PCM CONNECTO R F (8P )
NOTE: Standar d batter y voltag e is 1 2 V .
*2: '9 7 - 9 8 model s
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