1996 ACURA RL KA9 ECU

Fuel Supply System

Description

By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.

If a
malfunction
has
been detected during
two
consecutive
trips,
the MIL
will
come
on and DTC
P0171, P0172,
P0174

and/or P0175 will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as DTC P0171, P0172, P0174 and/or P0175, trou-

bleshoot those DTCs first, then troubleshoot DTC P0171, P0172, P0174 and/or P0175.

P0106*1, P0107, P0108, P1128*2, P1129*2: MAP Sensor

P0135: Right Primary HO2S Heater (Bank 1, Sensor 1)

P0137, P0138: Secondary HO2S (Sensor 2)

P0141: Secondary HO2S Heater (Sensor 2)

P0155: Left Primary HO2S Heater (Bank 2, Sensor 1)

P0401: EGR Flow Insufficient

P1491: EGR Valve Lift Insufficient

P1498: EGR Valve Position Sensor High Voltage

*1: '96 model only

*2: '97 - 01 models

DTC P0172, P0175

System too rich
• Fuel Pump insufficient flow/pressure

• Fuel Feed Line clogged, leaking

• Fuel Pressure Regulator stuck open

• Fuel Filter clogged

• Injector clogged, air inclusion

• Gasoline doesn't meet Owner's Manual spec.

• Primary HO2S (Sensor 1) deteriorated

• MAP Sensor range/performance*1

• EGR System insufficient flow

• Exhaust leak

• Fuel Pressure Regulator clogged, stuck closed

• Fuel Return Pipe clogged

• Injector leaking

• Gasoline doesn't meet Owner's Manual spec.

• Primary HO2S (Sensor 1) deteriorated

• MAP Sensor range/performance*1

• EGR System malfunction (too much flow)

• EVAP Canister Purge Valve leaking, stuck opened
DTCP0171, P0174

System too lean
The scan tool indicates Diagnostic Trouble Code (DTC) P0171: The fuel system is too lean [Right Bank (Bank 1)].

The scan tool indicates Diagnostic Trouble Code (DTC) P0172: The fuel system is too rich [Right Bank (Bank 1)].

The scan tool indicates Diagnostic Trouble Code (DTC) P0174: The fuel system is too lean [Left Bank (Bank 2)].

The scan tool indicates Diagnostic Trouble Code (DTC) P0175: The fuel system is too rich [Left Bank (Bank 2)].

Possible CauseProCarManuals.com

PGM-FI System

Misfire Detected in One Cylinder

The scan tool indicates Diagnostic Trouble Code (DTC) P1203 or P1303: Cylinder 3 misfire detected.

The scan tool indicates Diagnostic Trouble Code (DTC) P1204 or P1304: Cylinder 4 misfire detected.

The scan tool indicates Diagnostic Trouble Code (DTC) P1205 or P1305: Cylinder 5 misfire detected.

Description

Misfire detection is accomplished by monitoring the voltage of the spark plug with the spark plug voltage sensor which is

built into the ignition coil.

If misfiring strong enough to damage the catalyst is detected, the MIL will blink during the time of its occurrence, and a

misfire DTC will be stored. Then, after the misfire has ceased, the MIL will come on and stay on whenever the ignition

switch is ON (II).

If misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and a misfire

DTC will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as a misfire DTC, troubleshoot those DTCs first, then

troubleshoot the misfire DTC.

P0106*1, P1128*2, P1129*2: MAP sensor

P0171, P0172, P0174, P0175: Fuel supply system

P0401, P1491, P1498: EGR system

P1316, P1317, P1318, P1319: Spark Plug Voltage Detection System

P0335, P0336, P1336, P1337: CKP sensor

P1381, P1382, P1386, P1387: CYP sensor

*1: '96 model only

*2: '97 - 01 models

Possible Cause

Injector clogging, fuel leakage, air leakage

Injector circuit open or shorted

Injector resistor malfunction

Spark plug carbon deposits, fouling, malfunction

Ignition coil malfunction

ICM malfunction

Compression low
or

The scan tool indicates Diagnostic Trouble Code (DTC) P1206 or P1306: Cylinder 6 misfire detected.
or
or
or
The scan tool indicates Diagnostic Trouble Code (DTC) P1201 or P1301: Cylinder 1 misfire detected.

The scan tool indicates Diagnostic Trouble Code (DTC) P1202 or P1302: Cylinder 2 misfire detected.
or
orProCarManuals.com

PGM-FI Syste m
Rando m Misfir e
The sca n too l indicate s Diagnosti c Troubl e Cod e (DTC ) P0300*3,
P1300*4 an d som e o f P120 1 - P120 6 o r som e o f P130 1 - P1306 :
Rando m misfire .
Descriptio n
Misfir e detectio n i s accomplishe d b y monitorin g th e voltag e o f th e spar k plu g wit h th e spar k plu g voltag e senso r whic h i s
buil t i n to th e ignitio n coil .
If misfirin g stron g enoug h t o damag e th e catalys t i s detected , th e MI L wil l blin k durin g th e tim e o f it s occurrence , an d DT C
P1300*3 o r P0300*4, som e o f DTC s P120 1 throug h P120 6 o r som e o f DTC s P130 1 throug h P130 6 wil l b e stored . Then , afte r
misfir e ha s ceased , th e MI L wil l com e o n an d sta y o n wheneve r th e ignitio n switc h i s O N (II) .
I f misfirin g tha t increase s emission s i s detecte d durin g tw o consecutiv e drivin g cycles , th e MI L wil l com e on , an d DT C
P1300*
3 o r P0300*4, som e o f DTC s P120 1 throug h P120 6 o r som e o f DTC s P130 1 throug h P130 6 wil l b e stored .
NOTE : I f som e o f th e DTC s liste d belo w ar e store d a t th e sam e tim e a s a misfir e DTC , troubleshoo t thos e DTC s first , the n
troubleshoo t th e misfir e DTC .
P0106*1, P1128*2, P1129*2: MA P senso r
P0171 , P0172 , P0174 , P0175 : Fue l meterin g
P0401 , P1491 , PU98 : EG R syste m
P0335 , P0336 , P1336 , P1337 , P1381 , P1382 , P1386 , P1387 : CKP/CY P senso r
P0505 : Idl e Contro l Syste m
PI508 : IA C valv e
*1 : '9 6 mode l onl y
*2 : '9 7 - 0 1 model s
*3: '9 6 - 9 7 model s
*4: '9 8 - 0 1 model s
Possibl e Caus e
Fuel pum p insufficien t fue l pressure , amoun t o f flo w
Fue l lin e clogging , blockage , leakag e
Fue l filte r cloggin g
Fue l pressur e regulato r stuc k ope n
EG R syste m malfunctio n
Ignitio n coi l wir e open , leakag e
Ignition contro l modul e malfunction
MA P senso r range/performance , poo r response*1
IA C valv e malfunctio n
Fas t idl e therm o valv e malfunctio n
Carbo n deposit s o n valve s
Compressio n lo w
Gasolin e doe s no t mee t Owner' s Manua l spec. , lac k o f fue l
Troubleshootin g
By test-driving , determin e th e condition s durin g whic h misfir e occurs . Dependin g o n thes e conditions , tes t i n th e orde r
describe d i n th e tabl e below .
NOTE : I f misfir e doesn' t recur , som e possibl e cause s ar e fue l tha t doesn' t mee t owner' s manua l spec , lac k o f fuel , carbo n
deposit s o n spar k plug , etc .
11-166 11-69 section 4 section 4 section 6 11-102
and
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Before connectin g a ne w fue l tube/quick-connec t fittin g
assembly , remov e th e ol d retaine r fro m th e matin g pipe .
With th etab s pulle d
apart , pul l
th e retaine r
off
Ne w FUE L TUBE /
QUICK-CONNEC T
FITTIN G ASSEMBL Y
3. Alig n th e quick-connec t fitting s wit h th e pipe , an d
align th e retaine r lockin g pawl s wit h th e connecto r
grooves. The n pres s th e quick-connec t fitting s ont o
th e pip e unti l bot h retaine r pawl s loc k wit h a click -
in g sound .
NOTE : I f i t i s har d t o connect , pu t a smal l amoun t
o f ne w engin e oi l o n th e pip e end .
Connectio n wit h ne w retainer :
CONNECTO R
RETAINER
RETAINE R
PIPE
4. Mak e sur e th e connectio n i s secur e an d th e pawl s
ar e firml y locke d int o place ; chec k visuall y an d b y
pullin g th e connector .
Pull apart .
CONNECTO R
RETAINERPIPE
5. Reconnec t th e batter y negativ e cable , an d tur n th e
ignitio n switc h O N (II) . Th e fue l pum p wil l ru n fo r
abou t tw o seconds , an d fue l pressur e wil l rise .
Repea t 2 o r 3 times , an d chec k tha t ther e is n o leak -
ag e in th e fue l suppl y system .
CONNECTO R
Reconnectio n to existin g retainer :
PIPE
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Intake Air System

System Description

The system supplies air for all engine needs. It consists of the intake air pipe. Air Cleaner, intake air duct. Throttle Body,

Idle Air Control (IAC) Valve, idle air control thermal valve, and intake manifold.

A resonator in the intake air pipe provides additional silencing as air is drawn into the system.

IMRC SOLENOID VALVE 2

IMRC

SOLENOID

VALVE 1
IMRC

VACUUM

TANK

From No. 20 ECU

(PCM)
(20 A)

FUSE

(in the under-dash

fuse/relay box)

IMRC

DIAPHRAGM

VALVE 1
VARIOUS

SENSORS

THROTTLE BODY
INTAKE

AIR

DUCT
INTAKE

MANIFOLD
IDLE

ADJUSTING

SCREW
With

TCS

IDLE AIR

CONTROL

THERMAL

VALVE
IAC

VALVE
From PGM-FI

MAIN RELAY

IMRC

DIAPHRAGM

VALVE 2
IMRC

CHECK

VALVE

ENGINE

COOLANTProCarManuals.com

The sca n too l indicate s Diagnosti c Troubl e Cod e (DTC ) P0420 : Catalys t syste m efficienc y belo w threshold .
Descriptio n
This syste m evaluate s th e catalyst' s capacit y b y mean s o f th e HO2 S (Primar y an d Secondary ) outpu t durin g stabl e drivin g
conditions . I f deterioratio n ha s bee n detecte d durin g tw o consecutiv e drivin g cycles , th e MI L come s o n an d DT C P042 0 wil l
be stored .
NOTE : I f som e o f th e DTC s liste d belo w ar e store d a t th e sam e tim e a s DT C P0420 , troubleshoo t thos e DTC s first , the n
troubleshoo t DT C P0420 .
P0136 , P0139 : Secondar y HO2 S
P0141 : Secondar y HO2 S Heate r
Possibl e Caus e
• TW C Deterioratio n
• Exhaus t syste m leakag e
Troubleshootin g Flowchar t
— Th e MI L ha s bee n reporte d on .
— DT C P042 0 is stored .
Proble m verification :
1 . D o th e PC M Rese t Procedure .
2 . 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 .
3 . Connec t th e AC S servic e con -
nector .
4 . Test-driv e 4 0 - 5 5 mp h (6 4 -
8 8 km/h ) fo r approx . 2 min -
utes . The n decelerat e fo r a t
leas t 3 second s wit h th e throt -
tl e completel y closed . The n
reduc e th e vehicl e spee d t o
3 5 mp h (5 6 km/h) , an d tr y t o
hol d it unti l th e readines s cod e
come s on .
I s DT C P042 0 indicated ?
YES
Chec k th e TW C (se e sectio n 9 ).
I f necessary , replac e th e TWC . Intermitten
t failure , syste m is O K
at thi s time .
NO
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Emission Control System

Exhaust Gas Recirculation (EGR) System

Description

The EGR system is designed to reduce oxides of nitrogen emissions (NOx) by recirculating exhaust gas through the EGR

valve and the intake manifold into the combustion chambers. It is composed of the EGR valve, EGR valve vacuum control

valve, EGR valve vacuum control solenoid valve, PCM and various sensors.

The PCM contains memories for ideal EGR valve lifts for varying operating conditions. The EGR valve position sensor

detects the amount of EGR valve lift and sends the information to the PCM. The PCM then compares it with the ideal EGR

valve lift which is determined by signals sent from the other sensors. If there is any difference between the two, the PCM

cuts current to the EGR valve vacuum control solenoid valve to reduce vacuum applied to the EGR valve.

EGR VALVE

POSITION SENSOR
INTAKE MANIFOLD

From No. 20 ECU (PCM)

(20 A) FUSE

(in the under-dash

fuse/relay box)

VARIOUS

SENSORS

EGR VALVE

EGR VALVE

VACUUM

CONTROL

SOLENOID

VALVE
EGR VALVE

VACUUM

CONTROL

VALVEProCarManuals.com

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