1996 ACURA RL KA9 change time

PCM Data

You can retrieve data from the PCM by connecting the OBD II scan tool or the Honda PGM Tester to the Data Link

Connector (DLC). The items listed in the table below conform to SAE recommended practice. The Honda PGM Tester also

reads data beyond that recommended by SAE so that this data may help you find the causes of intermittent problems.

NOTE:

• The "operating values" listed are approximate and may vary depending on the environment and the individual vehicle.

• Unless noted otherwise, "at idle speed" means idling with the engine completely warmed up, transmission in Park or

neutral, and the A/C and all accessories turned off.

Data
Description
Operating Value

Freeze Data

Diagnostic

Trouble Code

(DTC)
If the PCM detects a problem, it will store it as a code

consisting of one letter and four numbers.

Depending on the problem, an SAE-defined code

(P0xxx)
or a
Honda-defined code
(P1xxx)
will
be
output

to the tester.
If no problem is detected,

there is no output.

YES

Engine Speed
The PCM computes engine speed from the signals sent

from the Crankshaft Position (CKP) sensor.

This data is used for determining the time and amount

of fuel injection.
Nearly the same as

tachometer indication at

idle speed:

650 ± 50 rpm
YES

Vehicle Speed
The PCM converts pulse signals from the Vehicle

Speed Sensor (VSS) into speed data.
Nearly the same as

speedometer indication
YES

Manifold

Absolute

Pressure (MAP)
The absolute pressure created in the intake manifold by

engine load and speed.
With engine stopped:

Nearly the same as atmo-

spheric pressure.

At idle speed:

24 - 37
kPa
(180
-
280

mmHg, 7.1 - 11.0 inHg)
YES

Engine Coolant

Temperature

(ECT)
The ECT sensor converts coolant temperature into

voltage and signals the PCM. The sensor is a thermistor

whose internal resistance changes with coolant

temperature. The PCM uses the voltage signals from

the ECT sensor to determine the amount of injected

fuel.
With cold engine:

Same as ambient temper-

ature and IAT

With engine warmed up:

approx. 158 - 212°F

(70 - 100°C)
YES

Heated Oxygen

Sensor (HO2S)

(Bank 1, Sensor 1)

(Bank 2, Sensor 1)

(Sensor 2)
The HO2S detects the oxygen content in the exhaust

gas and sends voltage signals to the PCM. Based on

these signals, the PCM controls the air/fuel ratio. When

the oxygen content is high (that is, when the ratio is

leaner than the stoichiometric ratio), the voltage signal

is lower. When the oxygen content is low (that is, when

the ratio is richer than the stoichiometric ratio), the

voltage signal is higher.
0.0 -
1.25
V

At idle speed:

about 0.1 - 0.9 V

NOProCarManuals.com

PGM-FI Syste m
Throttl e Positio n (TP ) Senso r
The sca n too l indicate s Diagnosti c Troubl e Cod e (DTC ) P0122 : A lo w voltag e proble m in th e Throttl e Positio n
(TP) senso r circuit .
The T P Senso r i s a potentiometer . I t i s connecte d t o th e throttl e valv e shaft . A s th e throttl e positio n changes , th e throttl e
position senso r varie s th e voltag e signa l t o th e PCM .
— Th e MI L ha s bee n reporte d on .
— DT C P012 2 is stored .
Proble m verification :
1 . Star t th e engine . Hol d th e
engin e a t 3,00 0 rp m wit h n o
loa d (i n Par k o r neutral ) unti l
th e radiato r fa n come s on ,
the n tur n th e ignitio n switc h
OFF.2. Turn the ignition switch ON (II).3. Chec k th e throttl e positio n
wit h th e sca n tool .
I s ther e approx . 10 % whe n
the throttl e is full y close dand approx . 90 % whe n th e
throttl e is full y opened ?
NO
Chec k fo r a n ope n i n the wire
(VCC 2 line) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e T P senso r con -
nector .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n
No. 1 termina l an d No . 3 termi -nal o n th e T P senso r connector . BRUS
H
HOLDE R
BRUS H
RESISTO R
YES
Is ther e abou t 5 V ?NO
YE S
Chec k fo r a n ope n o r shor t i n T Psensor :1. Tur n th e ignitio n switc h OFF .
2 . Measur e resistanc e betwee n
No . 1 termina l an d No . 2 ter -
mina l o n th e senso r sid e o f
T P senso r connecto r wit h th e
throttl e full y closed .
(T o pag e 11-81 )
*: wit h TC S*1: wit h VS A TERMINA
L
INNERBUSHIN GIDLEFUL LTHROTTL E
THROTTLEOPENING
Intermitten t failure , syste m is O K
a t thi s time . Chec k fo r poo r con -
nection s o r loos e wire s a t C11 3
(T P sensor ) C251 , C253 , C25 4
(locate d a t lef t shoc k tower) ,
C62 3 (TC S contro l unit) * C45 0
(VS A converte r unit)*
1 an d PCM . T
P SENSO R CONNECTO R (C113 )
Wir e sid e o f femal e terminal s
Chec k fo r a n ope n in wir e (VCC2 ,
line):Measur e voltag e betwee n D2 1
termina l an d D2 2 termina l o n th e
PC M connector . Wir
e sid e o f femal e terminal s
I s ther e abou t 5 V ? Repai
r ope n in th e wir e betwee n
PCM (D21 ) an d T P sensor .
NO
Substitut e a known-goo d PC M
an d rechec k (se e pag e 11-42 fo r
immobilize r information) . I f pre -
scribe d voltag e is no w available ,
replac e th e origina l PCM .Termina l sid e o fmal e terminal s
YES
PCM CONNECTO R D (22P )
OUTPU
T VOLTAG E (V )
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Troubleshooting Flowchar t
— Th e MI L ha s bee n reporte d on .
— DT C P120 1 throug h P120 6 o r
P130 1 throug h P130 6 i s indi -
cated .
Proble m verification :
1 . Afte r checkin g th e freez e data ,
d o th e PC M Rese t Procedure .
2 . Connec t th e SC S servic e con -
nector .
3 . Test-driv e th e ca r severa l time s
i n th e rang e o f th e freez e data .
I s an y misfir e DT C indicated ?
Doe s th e misfir e occu r i n th e othe r
cylinde r whos e spar k plu g wa s
exchanged ?
NO
Chec k fo r ignitio n coi l malfunction :
1 . Exchang e th e ignitio n coi l fro m
th e proble m cylinde r wit h on e
fro m anothe r cylinder .
2 . Test-driv e th e ca r severa l time s
i n th e rang e o f th e freez e data .
I s an y misfir e DT C indicated ?
YES
Doe s th e misfir e occu r i n th e othe rcylinde r whos e ignitio n coi l wa sexchanged ?
NO
(T o pag e 11-98 )
NOTE :• I f ther e i s n o freez e dat a o f misfiring ,
jus t clea r th e DTC .
• I f ther e i s n o freez e dat a o f misfiring ,
tes t drive s unde r variou s condition s ar e
necessary .
Intermittent misfir e du e t o spar kplug fouling , etc . (firin g i s O K a t
thi s time) .
Replac e th e fault y spar k plug .
Intermitten t misfir e du e t o ba d
contac t i n th e ignitio n coi l con -
necto r (firin g is O K a t thi s time) .
Replac e th e fault y ignitio n coil .
YES
NO
YE S
1. Exchang e th e spar k plu g fro mthe proble m cylinde r wit h on eof anothe r cylinder .
2 . Test-driv e th e ca r severa l time s
i n th e rang e o f th e freez e data .
YES
NO
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PGM-FI Syste m
Misfire Detecte d in On e Cylinde r (cont'd )
(From pag e 11-97 )
Chec k th e injecto r function :
Liste n fo r a clickin g soun d a t th e
injecto r i n th e proble m cylinder .
Doe s i t click ?
NO
YE SChec k fo r a n ope n o r shor t i n th e
harnes s betwee n th e PC M an d
the injector .
Are th e wire s OK ?
Chec k fo r injecto r malfunction :
1 . Exchang e th e injecto r fro m th e
proble m cylinde r wit h on efrom anothe r cylinder .
2 . Le t th e engin e idl e fo r 2 min -
utes .
3 . Test-driv e th e ca r severa l time s
i n th e rang e o f th e freez e data . Repai
r ope n o r shor t i n th e wire .
YES
— Replac e th e injector .
— Substitut e a known-goo d PC M
an d rechec k (se e pag e 11-42
fo r immobilize r information) . I f
symptom/indicatio n goe s
away , replac e th e origina l
PCM.
NOTE : I f ther e is n o freez e dat a o f mis -
firing , tes t drive s unde r variou s condi -
tion s ar e necessary .
I s an y misfir e DT C indicated ?
YES
Intermitten t misfir e du e t o ba d
contac t i n th e injecto r connecto r
(firin g is O K a t thi s time) .
Doe s th e misfir e occu r i n th e othe r
cylinde r whos e injecto r wa sexchanged ?Replace th e fault y injector .
NO
(T o pag e 11-99 )
YES
NO
N O
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Idle Contro l Syste m
System Descriptio n
The idl e spee d o f th e engin e is controlle d b y th e Idl e Ai r Contro l (IAC ) Valve .
Th e valv e change s th e amoun t o f ai r bypassin g int o th e intak e manifol d i n respons e t o electri c curren t controlle d b y th e
PCM . Whe n th e IA C Valv e is activated , th e valv e open s to maintai n th e prope r idl e speed .
VARIOU S
SENSOR S
INTAK E
MANIFOL D
IDLEADJUSTIN GSCREW
1. Afte r th e engin e starts , th e IA C valv e open s fo r a certai n time . Th e amoun t o f ai r i s increase d t o rais e th e idl e spee d
abou t 15 0 - 30 0 rpm .
2 . Whe n th e coolan t temperatur e i s low , th e IA C valv e i s opene d t o obtai n th e prope r fas t idl e speed . Th e amoun t o f
bypasse d ai r i s thu s controlle d in relatio n to th e engin e coolan t temperature .
3 . Whe n th e idl e spee d is ou t o f specificatio n an d th e sca n too l doe s no t indicat e Diagnosti c Troubl e Cod e (DTC ) P050 5 o r
P1508 , chec k th e followin g items :
• Adjus t th e idl e spee d (se e pag e 11-124 )
• Ai r conditionin g signa l (se e pag e 11-116 )
• AL T F R signa l (se e pag e 11-118 )
• Starte r switc h signa l (se e pag e 11-119 )
• Transmissio n rang e signa l (se e sectio n 14 )
• PS P switc h signa l (se e pag e 11-120 )
• Brak e peda l positio n switc h signa l (se e pag e 11-122 )
• Idl e ai r contro l therma l valv e (se e pag e 11-123 )
• Hose s an d connection s
• IA C valv e an d it s mountin g O-ring s
4 . I f th e abov e item s ar e normal , substitut e a known-goo d IA C valv e an d readjus t th e idl e spee d (se e pag e 11-124 ).
I f th e idl e spee d stil l canno t b e adjuste d t o specificatio n (an d th e sca n too l doe s no t indicat e DT C P050 5 o r P1508 ) afte r
IA C valv e replacement , substitut e a known-goo d PC M an d rechec k (se e pag e 11-42 fo r immobilize r information) . I f
sympto m goe s away , replac e th e origina l PCM .
IDLEAIRCONTRO LTHERMA LVALVE
IAC VALV E
FromPGM-F IMAINRELA Y
ENGIN E COOLAN T
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— Th e MI L ha s bee n reporte d on .
— DT C P150 8 is stored .
Proble m verification :
1. D o th e PC M Rese t Procedure .2. Star t th e engine .
Is DT C P150 8 indicated ?
YES
Chec k fo r a n ope n i n the wire
(IGP 1 line) :
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e IA C valv e con -
nector .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n bod y
groun d an d th e IA C valv e con -
necto r termina l No . 2 .
I s ther e batter y voltage ?
I s ther e batter y voltage ?
YES
Chec k th e IA C valv e function :
Momentaril y connec t PC M con -
necto r terminal s A 5 an d A1 2 wit h
a jumpe r wire severa l times .
Doe s th e IA C valv e click ?
YES
Substitut e a known-goo d PC M
an d rechec k (se e pag e 11-42 fo r
immobilize r information) . I f symp -
tom/indicatio n goe s away , replac e
th e origina l PCM .
SHAF T
Intermitten t failure , syste m is O K
a t thi s time . Chec k fo r poo r con -
nection s o r loos e wire s a t C25 3
(locate d a t lef t shoc k tower) ,
C12 9 (IA C valve ) an d PCM .
SPRIN G
IAC VALV E CONNECTO R (C129 )
Repair ope n in th e wir e betwee n
IA C valv e an d PGM-F I mai n relay . Wir
e sid e o f femal e terminal s
PCM CONNECTO R A (26P )
Repai r ope n o r shor t i n th e wir e
betwee n PC M (A5 ) an d IA C valve . Wir
e sid e o f femal e terminal sJUMPER WIR E
Replac e th e IA C valve .NO
NO
Chec k fo r a n ope n o r shor t i n th ewir e (IAC V line) :
1 . Tur n th e ignitio n switc h OF F
an d reconnec t th e IA C valv e
connector .2. Disconnec t th e PC M connec -tor A (26P) .3. Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n
bod y groun d an d PC M con -
necto r termina l A5 .
NO
YE S
VALV E
To INTAK EMANIFOL DFrom AI RCLEANE RCOIL
NO
Idl e Ai r Contro l (IAC ) Valv e
The sca n too l indicate s Diagnosti c Troubl e Cod e (DTC ) P1508 : A proble m in th e Idl e Ai r Contro l (IAC ) valv e
circuit .
The IA C Valv e change s th e amoun t o f ai r bypassin g th e throttl e bod y i n respons e t o a curren t signa l fro m th e PC M in
orde r t o maintai n th e prope r idl e speed .
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The scan tool indicates Diagnostic Trouble Code (DTC) P0420: Insufficient flow in the Exhaust Gas Recirculation

(EGR)
system.

Description

Deterioration (clogging, leakage, etc.) in the EGR line or EGR valve is detected by means of the changes in manifold abso-

lute pressure before and after the operation of the EGR valve.

If deterioration has been detected during two consecutive driving cycles, the MIL will come on and DTC P0401 will be

stored.

Possible Causes

• Clogging, leakage in the EGR line

• Faulty EGR valve

Troubleshooting Flowchart

Is DTC P0401 indicated?
Intermittent failure, system is OK

at this time.

YES

Clean the intake manifold EGR

port and EGR passage with car-

buretor cleaner.

Clean the passage inside the

EGR valve with carburetor

cleaner or replace the valve.
NO
Problem verification:

1. Do the PCM Reset Procedure.

2. Connect the ACS service con-

nector.

3. Test-drive under the following

conditions.

— Without any electrical load

— Transmission in posi-

tion

— Decelerate from 55 mph

(88 km/h) for at least 5 sec-

onds.
The MIL has been reported on.

DTC P0401 is stored.ProCarManuals.com

Master Cylinder/Brak e Booste r
Brake Booste r Inspectio n
Functiona l Tes t
1 . Wit h th e engin e stopped , pres s th e brak e peda l sev -
eral time s t o deplet e th e vacuu m reservoir , the n
pres s th e peda l har d an d hol d i t fo r 1 5 seconds . I f
th e peda l sinks , eithe r th e maste r cylinde r i s
bypassin g internally , o r th e brak e syste m (maste r
cylinder , lines , modulator , o r caliper ) i s leaking .
2 . Star t th e engin e wit h th e peda l pressed . I f th e peda l
sinks slightly , th e vacuu m booste r i s operatin g nor -
mally . I f th e peda l heigh t doe s no t vary , th e booste r
o r chec k valv e is faulty .
3. Wit h th e engin e running , pres s th e brak e peda l light -
ly. Appl y jus t enoug h pressur e t o hol d bac k auto -
mati c transmissio n creep . I f th e brak e peda l sink s
mor e tha n 2 5 m m (1. 0 in. ) i n 3 minutes , th e maste r
cylinde r i s faulty . A sligh t chang e i n peda l heigh t
whe n th e A/ C compresso r cycle s o n an d of f i s nor -
mal . (Th e A/ C compresso r loa d change s th e vacuu m
availabl e to th e booster. )
Leak Tes t
1 . Pres s th e brak e peda l wit h th e engin e running , the n
sto p th e engine . I f th e peda l heigh t doe s no t var y
whil e presse d fo r 3 0 seconds , th e vacuu m booste r i s
OK . I f th e peda l rises , th e booste r i s faulty .
2 . Wit h th e engin e stopped , pres s th e brak e peda l sev -
era l time s usin g norma l pressure . Whe n th e peda l i s
firs t pressed , i t shoul d b e low . O n consecutiv e appli -
cations , th e peda l heigh t shoul d graduall y rise . I f th e
peda l positio n doe s no t vary , chec k th e booste r
chec k valve .
Booste r Chec k Valv e Tes t
1 . Disconnec t th e brak e booste r vacuu m hos e a t th e
booster .
2 . Star t th e engine , an d le t i t idle . Ther e shoul d b e vac -
uum . I f n o vacuu m is available , th e chec k valv e i s
no t workin g properly . Replac e th e brak e booste r
vacuu m hos e an d chec k valve , an d retest .
NOTE : '9 6 - 9 7 model s shown .
BRAKE BOOSTE RVACUUM HOS E
(Chec k valv e is
built-in )
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