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
Troubleshooting Procedure s
Checking th e Diagnosti c Troubl e Cod e (DTC )
wit h a n OB D II Sca n Too l o r Hond a PG M Teste r
When th e PC M sense s a n abnormalit y i n th e inpu t o r outpu t systems , th e indicato r ligh t i n th e gaug e assembl y wil l
blink . Whe n th e 16 P Dat a Lin k Connecto r (DLC ) (locate d behin d th e ashtray ) i s connecte d to th e OB D II Sca n Too l o r Hond a
PG M Teste r a s shown , th e sca n too l o r teste r wil l indicat e th e Diagnosti c Troubl e Cod e (DTC ) whe n th e ignitio n switc h i s
turne d O N (II) .
If th e indicato r ligh t o r th e MI L ha s bee n reporte d on , o r i f a driveabilit y proble m is suspected , follo w thi s procedure :
1 . Connec t th e OB D II Sca n Too l (conformin g to SA E J1978 ) o r Hond a PG M Teste r t o th e 16 P DLC .
(Se e th e OB D II Sca n Too l o r Hond a PG M Teste r user' s manua l fo r specifi c instructions . I f yo u ar e usin g th e Hond a
PG M Tester , mak e sur e it i s se t t o th e SA E DT C type. )
2 . Tur n th e ignitio n switc h O N (II) , an d observ e th e DT C o n th e screen .
3 . Recor d al l fue l an d emission s DTCs , A/ T DTCs , an d freez e data .
4 . I f ther e is a fue l an d emission s DTC , firs t chec k th e fue l an d emission s syste m a s indicate d b y th e DT C (excep t fo r DT C
P0700) . DT C P070 0 mean s ther e is on e o r mor e A/ T DTC , an d n o problem s wer e detecte d in th e fue l an d emission s circui t
of th e PCM .
5. Ge t th e anti-thef t cod e fo r th e radio , the n writ e dow n th e radi o statio n presets .
6 . Rese t th e memor y wit h th e PG M Teste r o r b y removin g th e BAC K U P fus e i n th e under-hoo d fuse/rela y bo x fo r mor e
tha n 1 0 seconds .
7 . Driv e th e vehicl e fo r severa l minute s a t speed s ove r 3 0 mp h (5 0 km/h) , an d the n rechec k fo r DTCs . I f th e A/ T DT C
returns , g o t o th e Symptom-to-Componen t Char t (pag e 14-5 6 an d 14-57 ). I f th e DT C doe s no t return , ther e wa s a n inter -
mitten t proble m withi n th e circuit . Mak e sur e al l pin s an d terminal s i n th e circui t ar e tight , an d the n g o t o ste p 8 .
8 . Ente r th e anti-thef t cod e fo r th e radio , rese t th e radi o prese t stations , an d se t th e clock .
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Checking th e Diagnosti c Troubl e Cod e (DTC )
wit h th e Servic e Chec k Connecto r an d Specia l Too l
Whe n th e PC M sense s a n abnormalit y in th e inpu t o r outpu t systems , th e indicato r ligh t i n th e gaug e assembl y wil l blink .
Whe n th e Servic e Chec k Connecto r (locate d unde r th e das h o n th e passenge r side ) i s connecte d wit h th e specia l too l a s
shown , th e indicato r ligh t wil l blin k th e Diagnosti c Troubl e Cod e (DTC ) whe n th e ignitio n switc h i s turne d O N (II) .
Whe n th e indicato r ligh t ha s bee n reporte d on , connec t th e Servic e Chec k Connecto r wit h th e specia l tool .
Then tur n th e ignitio n switc h O N (II ) an d observ e th e indicato r light .
INDICATO RLIGHT
Code s 1 throug h 9 ar e indicate d b y individua l shor t blinks . Code s 1 0 an d abov e ar e indicate d b y a serie s o f lon g an d shor t
blinks . On e lon g blin k equal s 1 0 shor t blinks . Ad d th e lon g an d shor t blink s togethe r t o determin e th e code . Afte r deter -
minin g th e code , refe r t o th e electrica l syste m Symptom-to-Componen t Char t o n page s 14-5 6 an d 14-57 .
NOTE :
• Disconnectin g th e BAC K UP , RADI O fus e als o cancel s th e radi o anti-thef t code , prese t station s an d th e cloc k setting . Ge t
th e customer' s cod e number , an d mak e not e o f th e radi o preset s befor e removin g th e fus e s o yo u ca n rese t them .
• Th e PC M memor y mus t b e rese t afte r reconnectin g th e batter y o r th e BAC K UP , RADI O fus e (se e pag e 11-111 ).
SC S SERVIC E CONNECTO R07PAZ-001010 0
GAUGE ASSEMBL Y
SERVICE CHEC KCONNECTO R (2P )
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PCM Rese t Procedur e
1 . Mak e sur e yo u hav e th e anti-thef t cod e fo r th e radio , the n writ e dow n th e frequencie s fo r th e radio' s prese t buttons .
2 . Tur n th e ignitio n switc h OFF .
3 . Remov e th e No . 5 6 BAC K UP , RADI O fus e (7. 5 A ) fro m th e under-hoo d fuse/rela y bo x fo r 1 0 second s t o rese t th e PCM .
NOTE :
• Th e A/ T contro l syste m memor y canno t b e cleare d b y usin g th e OB D II Sca n Too l o r Hond a PG M Tester ; b e sur e t o
remov e th e BAC K UP , RADI O fus e t o rese t th e A/ T contro l syste m memory .
• Th e PC M memor y mus t b e rese t afte r reconnectin g th e batter y o r th e BAC K UP , RADI O fus e (se e pag e 11-111 ).
BAC K UP , RADI O(7.5 A ) FUS E
UNDER-HOO DFUSE/RELAY BO XFina l Procedur e
NOTE : Thi s procedur e mus t b e don e afte r an y troubleshooting .
1 . Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e OB D II Sca n Too l o r Hond a PG M Teste r fro m th e Dat a Lin k Connecto r (16P) , o r remov e th e specia l too l
fro m th e Servic e Chec k Connector .
3. Rese t th e PCM .
4. Tur n th e ignitio n switc h O N (II) .
5 . Ente r th e anti-thef t cod e fo r th e radio , the n ente r th e customer' s radi o statio n presets .
6 . Memoriz e th e engin e idl e spee d signa l i n th e PC M (se e pag e 11-111 ).
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Transmission
Installation (cont'd )
TRANSMISSIO N HOUSIN GMOUNTIN G BOLT S12 x 1.2 5 m m64 N- m (6. 5 kgf-m , 4 7 Ibf-ft )
36. Instal l th e AT F dipstic k tub e bracke t bolts .
37 . Connec t th e transmissio n sub-harnes s connector .
38 . Instal l th e contro l box .
39 . Instal l th e stru t brace .
40 . Refil l th e transmissio n wit h th e recommende d AT F
(se e pag e 1 4-108 ).
41 . Connec t th e batter y positiv e (+ ) an d negativ e (- )
cable s t o th e batter y terminals .
42 . Se t th e parkin g brake . Star t th e engine , an d shif t th e
transmissio n throug h al l gear s thre e times . Chec k
th e shif t leve r operatio n an d th e A/ T gea r positio n
indicato r operation .
43 . Le t th e engin e reac h norma l operatin g temperatur e
(th e radiato r fa n come s on ) wit h th e transmissio n in
th e o r position , the n tur n it of f an d chec k AT F
level .
44 . Roa d tes t a s describe d o n page s 14-10 4 thr u 14-106 .
45 . Ente r th e anti-thef t radi o cod e fo r th e radio , the n
ente r th e customer' s radi o statio n presets .
46 . Memoriz e th e engin e idl e spee d signa l i n th e PC M
(se e pag e 11-111 ).
35
. Instal l th e transmissio n housin g mountin g bolts .
TRANSMISSIO NSUB-HARNES SCONNECTOR
6 x 1. 0 m m12 N- m (1. 2 kgf-m ,8.7 Ibf-ft )6 x 1. 0 m m12 N- m (1. 2 kgf-m ,8.7 Ibf-ft )
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Troubleshooting Precautions
ABS Indicator
1. If the system is OK, the ABS indicator goes off 2 seconds after turning the ignition switch ON (II) without starting the
engine, and then comes on again and goes off after 2 seconds. This occurs because the ABS control unit is turned on
by the IG2 power source.
2. The ABS indicator comes on when the ABS control unit detects a problem in the system. However, even though the
system is operating properly, the ABS indicator will come on, under the following conditions.
Only drive wheels rotate
One drive wheel is stuck
Vehicle spin
ABS continues to operate for a long time
Signal disturbance
To determine the actual cause of problem, question the customer about the problem, taking these conditions into con-
sideration.
3. When a problem is detected and the ABS indicator comes on, there are cases when the indicator stays on until the igni-
tion switch is turned OFF, and cases when the indicator goes off automatically when the system returns to normal. For
DTCs 61 and 62, the indicator goes off automatically when the system returns to normal. For all other codes, the indica-
tor stays on until the ignition switch is turned OFF.
4. For DTCs 12, 14, 16, 18, 21, 22, 23, 24, 51, 52 and 53, the indicator goes off when the vehicle is driven again and the sys-
tem is OK after the ignition switch is turned from OFF to ON (II). However, if the DTC is erased, the CPU is reset and the
indicator goes off right after the engine is started if the system is OK.
Diagnostic Trouble Code (DTC)
1. If the CPU cannot be activated and the indicator comes on, the DTC is not memorized.
2. The memory can hold any number of DTCs. However, when the same DTC is detected more than once, the later one is
written over the old one. Therefore, when the same problem is detected repeatedly, it is memorized as 1 DTC.
3. The DTCs are indicated in the order of ascending number, not in the order they occur.
4. The DTCs are memorized in the EEPROM (non-volatile memory). Therefore, the memorized DTCs cannot be canceled
by disconnecting the battery. Perform the specified procedures to erase the DTCs.
Self-diagnosis
1. Self-diagnosis can be classified into 2 categories.
• Initial diagnosis: Performed right after the engine starts and until the ABS indicator goes off.
• Regular diagnosis: Performed right after the initial diagnosis until the ignition switch is turned OFF.
2. When a problem is detected by self-diagnosis, the system.
Turns the fail-safe relay OFF
Turns the solenoid valve OFF
Turns the pump motor OFF
Turns the ABS indicator ONProCarManuals.com
Troubleshooting Precaution s
System Indicator s
If th e syste m is OK , th e AB S indicato r goe s of f onc e afte r turnin g th e ignitio n switc h O N (II ) withou t startin g th e engine ,
an d the n com e o n agai n an d g o of f severa l second s late r afte r startin g th e engine . Thi s occur s becaus e th e VS A contro l
uni t i s turne d o n b y th e IG 2 powe r source .
Th e AB S indicato r o r VS A syste m indicato r come s o n whe n th e VS A contro l uni t detect s a proble m in th e system .
Th e AB S indicato r o r VS A syste m indicato r wil l als o com e o n unde r thes e conditions , eve n thoug h th e syste m is oper -
atin g properly :
— Th e vehicl e goe s int o a spi n
— Th e AB S continue s t o operat e fo r a lon g tim e
— Th e vehicl e is subjecte d to a n electrica l signa l disturbanc e
I f ther e is a faul t i n th e PGM-F I system , onl y th e VS A syste m indicato r come s on .
Th e VS A Activatio n Indicato r wil l flas h whe n onl y th e driv e wheel s rotat e o r on e o f th e driv e wheel s is stuck . Whe n thi s
occurs , th e AB S indicato r an d VS A syste m indicato r d o no t com e on .
T o determin e th e actua l caus e o f th e problem , questio n th e custome r abou t th e problem , takin g thes e condition s int o con -
sideration .
Whe n a proble m is detecte d an d th e AB S o r VS A indicato r come s on , ther e ar e case s whe n th e indicato r stay s o n unti l
th e ignitio n switc h i s turne d OFF , an d case s whe n th e indicato r goe s of f automaticall y whe n th e syste m return s t o nor -
mal . Fo r DT C 6 1 an d 62 , th e indicato r goe s of f automaticall y whe n th e syste m return s t o normal . Fo r al l othe r codes ,
th e indicato r stay s o n unti l th e ignitio n switc h is turne d OFF .
Fo r DTC s 12 , 14 , 16 , 18 , 51 , 52 , 53 , 66 , 6 8 an d 84 , th e AB S indicato r goe s of f whe n th e vehicl e is drive n agai n an d th e
syste m is O K afte r th e ignitio n switc h is turne d fro m OF F to O N (II) . However , i f th e DT C is cleared , th e CP U reset s an d
th e indicato r goe s of f righ t afte r th e engin e is starte d if th e syste m is OK .
Th e AB S is no t operationa l whe n th e AB S indicato r i s ON ; th e VS A is no t operationa l whe n th e VS A indicato r i s ON .
Whe n th e VS A indicato r an d MI L ar e bot h ON , troubleshoo t th e PGM-F I syste m first .
Diagnosti c Troubl e Cod e (DTC )
Th e memor y ca n hol d an y numbe r o f DTCs . However , whe n th e sam e DT C is detecte d mor e tha n once , th e mor e recen t
DT C is writte n ove r th e earlie r one . Therefore , whe n th e sam e proble m is detecte d repeatedly , i t i s memorize d a s a sin -
gle DTC .
The DTC s ar e indicate d in ascendin g numbe r order , no t i n th e orde r the y occur .
Th e DTC s ar e memorize d in th e EEPRO M (non-volatil e memory) . Therefore , th e memorize d DTC s canno t b e cancele d
b y disconnectin g th e battery . Perfor m th e specifie d procedure s to clea r th e DTCs .
Self-diagnosi s
Self-diagnosis can be classifie d int o tw o categories :
— Initia l diagnosis : Performe d righ t afte r th e engin e start s an d unti l th e AB S o r VS A indicato r goe s off .
— Regula r diagnosis : Performe d righ t afte r th e initia l diagnosi s unti l th e ignitio n switc h is turne d OFF .
When a proble m is detecte d b y self-diagnosis , th e VS A contro l uni t shift s to fail-saf e mode .
Kickbac k
The pum p moto r operate s whe n th e AB S is functioning , an d th e flui d in th e reservoi r i s force d ou t t o th e maste r cylinder ,
causing kickbac k a t th e brak e pedal .
Pum p Moto r
Th e pum p moto r operate s whe n th e AB S is functioning .
The VS A contro l uni t check s th e pum p moto r operatio n durin g initia l diagnosi s whe n th e vehicl e is started .
You ma y hea r th e moto r operat e a t thi s time , bu t i t i s normal .
Brak e Flui d Replacement/Ai r Bleedin g
Brak e flui d replacemen t an d ai r bleedin g procedure s ar e identica l t o th e procedure s us e o n vehicle s no t equippe d wit h
VSA . T o eas e bleeding , star t wit h th e fron t wheels .
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Climate contro l uni t an d audi o uni t ('9 6 - 9 8 models) :
SR S component s ar e locate d in thi s area . Revie w th e SR S
componen t locations , precautions , an d procedure s i n th e
Restraint s ( sectio n 24 ) befor e performin g repair s o r ser -
vice .
1. Remov e th e consol e pane l (se e pag e 20-48 ).
2 . Remov e th e cente r ai r vent .
NOTE : Inser t a fla t meta l plat e unde r th e B clips ,
the n detac h th e B clip s b y pryin g up . Pul l th e cente r
ai r ven t backwar d whil e pryin g th e clips .
CENTE R AI RVEN T
3.
META L PROTECTIV EPLATE SEA T
Make sur e yo u hav e th e anti-thef t cod e fo r th e
radio , the n writ e dow n th e frequencie s fo r th e
radio' s prese t buttons. Remov
e th e bolts , the n pul l ou t th e climat e contro l
uni t an d audi o uni t a s a n assembly . Disconnec t th e
connector s an d antenn a leads , the n remov e it .
Bol t locations , 4
6 x 1. 0 m m9.8 N- m(1.0 kgf-m ,
7. 2 Ibf-ft ) CLIMAT
E
CONTRO L UNI TCONNECTOR S
CLIMAT E
CONTRO L UNI THAZAR DWARNIN GSWITCH
CONNECTO RCLOCKCONNECTO R
AUDIO UNI T
FRON T FO G
LIGH T SWITC H
CONNECTO R
ANTENNALEADS
AUDIO UNI TCONNECTOR S
REA R WINDO W
DEFOGGE R SWITC H
CONNECTO R
5. Installatio n i s th e revers e o f th e remova l procedure .
NOTE:
Make sur e th e connector s an d antenn a lea d ar e
connecte d properly .
Ente r th e anti-thef t cod e fo r th e radio , the n ente r
th e customer' s radi o statio n presets .
Clip location s
CLIPCLIP
CLIMAT E CONTRO LUNITDASHBOAR DUPPER BRACKE T
CLIP
PIN
PIN
CLI P
CLIMAT ECONTRO LUNIT
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