ACURA TL 1995 Service Repair Manual

II. Powertrain Control Module (PCM) Reset Procedure

Either of the following actions will reset the PCM

Use the OBD II scan tool or Honda PGM Tester to clear the PCM's memory.

NOTE: See the OBD II scan tool or Honda PGM Tester user's manuals for specific operating instructions.

Turn the ignition switch OFF. Remove the BACK UP RADIO (10 A) fuse from the under-hood fuse/relay box for

10 seconds.

BACK UP RADIO

(10 A) FUSE

UNDER-HOOD

FUSE/RELAY

BOX

III. Final Procedure (this procedure must be done after any troubleshooting)

1. Remove the SCS Service Connector if it is connected.

NOTE: If the SCS service connector is connected and there are no DTCs stored in the PCM, the MIL will stay

on when the ignition switch is turned ON (II).

2. Do the PCM Reset Procedure.

3. Turn the ignition switch OFF.

4. Disconnect the OBD II scan tool or Honda PGM Tester from the Data Link Connector (16P).ProCarManuals.com

Troubleshooting
Troubleshootin g Procedure s (cont'd )
If th e inspectio n fo r a particula r cod e require s voltag e o r resistanc e check s a t th e PC M connectors , remov e th e righ t
doo r sil l molding . Pul l th e carpe t bac k t o expos e th e PCM . Unbol t th e PC M cover , an d connec t th e backprob e set s an d
a digita l multimete r a s describe d below . Chec k th e syste m accordin g t o th e procedur e describe d fo r th e appropriat e code(s )
liste d o n th e followin g pages .
PCM COVE R
PCM
Ho w to Us e th e Backprob e Set s
Connec t th e backprob e adapter s t o th e stackin g patc h cords , an d connec t th e cord s t o a multimeter . Usin g th e wir e
insulatio n a s a guid e fo r th e contoure d ti p o f th e backprob e adapter , gentl y slid e th e ti p int o th e connecto r fro m th e wir e
side unti l i t come s i n contac t wit h termina l en d o f th e wire .
DIGITA L MULTIMETE R
(Commerciall y available ) o r
KS - AH M - 32 - 00 3
BACKPROB E SE T
07SA Z - 001000 A (Tw o required )
Backprob e Adapter
Stackin
g Patc h
Cor d
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CAUTION:

Puncturing the insulation on a wire can cause poor or intermittent electrical connections.

Bring the tester probe into contact with the terminal from the terminal side of wire harness connectors in the engine

compartment. For female connectors, just touch lightly with the tester probe and do not insert the probe.

RUBBER SEAL
TESTER PROBE

WIRE HARNESS

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Troubleshooting
Troubleshootin g Procedure s (cont'd )
Sympto m Char t
Liste d belo w ar e symptom s an d probabl e cause s fo r problem s tha t D O NO T caus e th e Malfunctio n Indicato r Lam p (MIL ) t o
com e on . I f th e MI L wa s reporte d on , g o to pag e 11-32 .
Troubleshoo t eac h probabl e caus e in th e orde r liste d (fro m lef t t o right ) unti l th e sympto m is eliminated .
Th e probabl e caus e an d troubleshootin g pag e referenc e ca n b e foun d below .
SYMPTO M
Engin e wil l no t star t
Har d startin g
Col d fas t idl e to o lo w
Col d fas t idl e to o hig h
Idl e spee d fluctuate s
Misfir e o r roug h runnin g
Lo w powe r
Engin e stall s
PROBABL E CAUS E
2, 3 , 21 , 13 , 1
2 , 10 , 12 , 20 , 2 1
5, 6 , 7 , 4
5 , 6 , 7 , 9 , 8
5 , 14 , 15 , 6 , 7 , 9 , 8
Troubleshoo t fo r misfir e o n page s 11-85 , 11-8 9
2, 8 , 9 , 11 , 18 , 17 , 19 , 1 0
2, 5 , 10 , 21 , 7 , 3 , 1 6
Othe r Probabl e Cause s fo r a n engin e tha t wil l no t start :
— Compressio n
— PGM-F I mai n rela y
— Engin e locke d u p
— Timin g bel t
Probabl e Caus e Lis t (for DTC chart see page 11-45).
—
Startin g syste m
— Ignitio n syste m
— Overheatin g
— Batter y
Probabl e Caus e
1
2
3
4
5
6
7
8
9
10
1 1
1 2
13
1 4
15
1 6
17
18
19
2 0
2 1
Pag e
11-5 3, 11-54
11-11 9
(See DTC chart)
(See DTC chart)
(See DTC chart)
11-113
11-11 4
11-136
11-13 5
(See DTC chart)
(See DTC chart)
(See DTC chart)
Sectio n 1 4
11-10 4
11-106
11-112
11-13 4
11-138
11-14 4
11-153
System
Powertrai n Contro l Modul e (PCM )
Fuel pressur e
Crankshaf t Position/Cylinde r Positio n senso r circui t
Intak e Ai r Temperatur e (IAT ) senso r circui t
Idl e Ai r Contro l (IAC ) Valv e
Fas t idl e therm o valv e
Idl e spee d adjustmen t
Throttl e bod y
Throttl e cabl e
Manifol d Absolut e Pressur e (MAP ) senso r
Throttl e Positio n (TP ) senso r
Barometri c pressur e (BARO ) senso r
A/ T gea r positio n signa l
Ai r Conditionin g Signa l
Alternato r F R Signa l
Brak e switc h signa l
Air Cleane r
Intake Ai r Bypas s (IAB ) contro l syste m an d intak e ai r duc t
Thre e Wa y Catalyti c Converte r (TWC )
Evaporativ e emissio n (EVAP ) contro l
Contaminate d fue l
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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