
Fuel and Emissions
Spocial Tools ................ 1 1-2
Compon€nt Location
lndex ................. ...... 11-3
System Description
Vacuum Connectiona .......,.................... 1 1 -8
Efectrical Connections ....,.,.,......,...,,.....,'11-12
Syst€m Connectors ...,...,.................-.--. 11-2O
T.oubloshooting
Troubleshooting Guido .......................... 1 1-32
Self -diagnostic Procedures .,..,............... 1 1 -34
How to Road Flowcharts ...................,... 11-39
PGM-Fl System
Systom Description .............................. 1 l-4O
Troubleshooting Flowcharts
Engine Control Moduls ............... ........... 1 1 -42
Heated Oxygon Sensor ......,.................. 1 1-46
Heated Oxyg€n Sonsol Heatel .....,......... 1 1 -47
Fuel Supply System ..............-............... 1 1-50
Manitold Absolute Pressure
Ssnsor ............................................ 1 1-52
Top D6ad Cente./Crankshatr
Position/Cylindor Position sonsor ........ 1 1 -56
Engine Coolant Tempsrature Sonsor ....... 11-58
Throttlo Position Sonsor ........,..,,........... 1 1-60
Intake Air Temperaturs Sensor ............... 11-62
Baromet c Prsssuro Sensor ......,...,...,..,. 11-64
lgnition Output Signal ........................... 1 1 -66
Vehicle Spe€d Sensor ........................... 1 1 -68
Electdcal Load Dotector ....,...,..........,.... 1 1 -7O
Knock Sensor [818C1 engine] ............... 11-74
A/T Fl Signal A/B ................................. 1 1-76
ldle Contlol System
System Troubleshooting Guide .................. 1 1 -78
Systom Description ........ 11-79
Troubloshooting Flowchans
ldl€ Ail Control Valve ........................... 1 1 -82
Ail Conditioning Signal ......................... 1 1 -84
Altemator FR Signal ............................. 1 1 -86
Automatic Transaxle (A/T) Gear
Position Signal ......... 11-88
Brake Switch Signal ............................. 1 1 -9O
Startel Switch Signal ............................ 11-92
Power Steering Pressure Switch Signal ... 11-93
Fast ldle Thermo Valve ...................,......... 1 1 -94
ldls Speed S€tting .................................... 1 1 -95
Fuel Supply System
Systam Tloubloshooting Guid. .................. 1 1 -97
Fuol Linos ...................... 1'l -98
System Description ........ 11-100
Fuol Prassure ................. 11-100
Fu6l Ini6ctors ................. 11-102
Fuel Pressure Ragulato. .,. 11-106
Fuel Filter ...................... 11-108
Fual Pump ..................... 11-109
PGM-Fl Main F6lay ................................... 1 1"1 1 1
Fuel Tank ...................... t 1-114
Intake Air System
System Troubloshooting Guido .................. 1 1 -1 1 5
Systom Dascription ........ 11-116
Air Clean€r .................... 11-117
Throttls Cable ................'11-118
Throttl8 Body ................ 11-120
lntake Air Bypass Cont.ol Systsm
[B18Cl enginal .,......... 11-123
Intake Manilold [B1881 onginol ................. 11-128
Emission Control System
Systsm Troubleshooting Guido .................. 1 1 -1 29
Systam Doscription ........ 11-130
Tailpips Emission ........... 11-130
Thrae Way Catalytic Convortor ...,...,........., 11-131
Positiva CrankcaEo V6ntilation Systcm .,....., 11-134
Evaporativo Emission Contro|,..,..,.,.,,.,,..,.., 1 1-135

AIR CLEAI{ER IACL)Replacoment,11-117
THROTTLE BODY (T8I
Inspsction, page 1 1-120Disassembfy, page 11'122THROTTLE CABLEInsDection/Adjustment, pages 1 l-'l 18, 1 19
Inslallation, pages 1 1-1 18, 119
POSITIVE CRA KCASEvEt{TtLATtOt{ (PcVl VALVEInspection, psgo 1 l-134
INTAKEAIREYPASS IIABIco TnoLSOLENOIDVALVE (B18Cl .ngino onlylTroubl6shooting,page 1 1-124
INTAKEAIRBYPASS (IABI
co TROLOIAPHRAGM{Bl8C1 ongino onlylTroubleshooting,page 11-124
I
RESONATOR
ENGI]TE CONTROL MODULE {ECM)Selt-diagnostic Procedures, page 1 1-34Troubfeshooting, page 1 1 -42
MAIN RELAYRelay Testing, page 1 1- 111Troubleshooting, pag€ 1 1-112SERVICE CHECX CONNECTOR (2PI
56ll.diagnostic Procedures, page'l 1-34
11-5

PGM-FI System
Engine Control Module (ECM)
lB18B1 ongino onlyl
The Malfunction Indicator Lamp(MlL) n6v6. com6s on lovon follwo socondal aftor ignition istumed on.
lurn the ignition switch ON.
Inspect No. 15 {BACK-UP LIGHT}l1O A) luse in the underdashtuse/relay box.ls the low oil pressure light on?
- R€placo No. 'l5
IBACK-UP LIGHT)llo Al fuso.- Ropair short inYEL wiro botwoonNo. 15 (BACK-UP
LIGHT) {10 A) fusoano gauge 6$om-blv.
Turn lhe ignition switch OFF.
ls the fuse OK?
Connecl the test harness betweenthe ECM and connectors (seepag€ 11-37).Repair opon in YEL wiio botw6onNo.'15 IBACK-UP LIGHTI 110 A)luso and gaug6 assombly.
Turn the ignition switch ON.
- RsDlaco tho MIL bulb.- Ropair opon in GRN/ORN wi.ebetwoen ECM {A13} andgaug€ a$6mbly.
ls the MIL on?
Measure voltage between body
Oround and the tollowing termi-nafs individuallv: 423, 424.
Ropah op6n in BLK wirolsl bo-tw6en ECM and GlOl llocatod atthormostat housing) that hadmoro than 1.0 V.
ls there less than 1.O V?
Substituto a known-good ECMand rochgck, lf symptom/indica-tion go€s away, roplaco tho origi-nal ECM.
NOTE: lf this svmptom is intermittent. check for a loose fuse No. 15 (BACK
UP LIGHT, 1OA) in the under-dash Juse/relay box, a poor connection at ECM
terminal A13, or an intermittent open in the GRN/ORN wire between the ECM(A13) and the gauge assembly.
I A13
I| | o oooo oooooooo I oooo oooo I ooooool ooooooooooo I
G 10' l
11-42

Th. ll.lfunction Indicltor Lamp
lMlll at!y3 on o. cornaa on alt6ltwo aacond!.
Connect the SCS short connectorto th6 sorvice check connector(see page 11-34).
Turn the ignition switch ON.
Go to iolfdiagnostic Proceduros(se€ pago 11-34).Does the MIL indicate anv Oi-agnostic Trouble Code (DTC)?
Romove th€ SCS shon connectorlrom the service ch€ck connector.
Turn the ignition switch OFF.
Try to start the engine.
Connect the test harness betweenthe ECM and connectors (see
page 11-37).
Turn the ignition switch ON.
Measure voltage botween D4 (+ )terminal and D22 { - ) terminal.
connect the SCS shonconnector to servlcecheck connector.ls there approx. 5 V?
Ropair shon to body g.ound inBRN/WHT wire betwoon th6 ECMlD4) end sorvlco chock connocto?.Measure voltage be_tween D4 {+} terminaland body ground.
- R6pair open in BRN/WHT witobotwoon EcM lD4) and s6rv-ice chock connactor.- Repoir opon in BLK wiro bo-twoon 36rvi@ chock connectoaand G4Ol.
ls there approx. 5 V?
InsDoct ECU {ECM) 115 A) tuse inth6 undeFhood luse/relav box.
- Rsolaco ECU {ECM} (15 Allus€.- R6pair shon in YEL/WHT wilobotw6on ECU lEcMl 115 A)fuso and PGM-FI main rolay.
Remove the scs shortConnector from theservice check con-nector.
ls the luss OK?
NOTE:
a When there is no code stored, the MIL willstay on if the service check con-
nector is shorted.
a tf this svmotom is intermittent, check for:
- A loose ECM fuse (15A) in the under-hood tuse/relay box
- A loose No. 24 fuse (ACG) (ALT) ( 1 5A: B1 8B 1 engine, 2OA: B18C 1 en-
gine) in the under-dash fuse/relay box- An intermittent short in the BRN/WHT wire between the ECM (D4) and
the service check connector- An intermittent oDen in the BLK wire between the service check con-
nector and G4O1- An intermittent shon in the GRN/ORN wire between the ECM (A 13) and
the gauge assembly.- An intermittent short in the YELMHT wire between the ECM (D19) and
the MAP sensor- An intermittent short in the YEL/BLU wire between the ECM (D20) and
the TP sensor
o ooooo ooo ooo o loooooooo liii:$A$.Ps,l o oo ooo ooooo
o oooo ooo o o ooo I oooooooooooooooooo
D4 (+)
l"oo,o'.
D22 t-l
uu,l
'NOTE: After repair, disconnect the SCS ShortConnsctor, test drive the car, and recheckthe MIL
lor a code.
(cont'd)
(To page 1 'l -44)lTo page 1 1-44)
11-43

(From page 1 1-43)
Inspect the No. 24ACG {ALT) (lG)(15 A: 81881 engine, 2OA:818C1 enginel fuse in the under-dash fuse/relav box.
- R.pllr .hon in BLK|rEL wlr6batr.v€qr undariair luro/Fbybox lnd FGM-FI m.in .obv.- noebco lto. 24 ACG {lG) nLT)(15 A: 81881 ongin., 2OA:Bl8Cl onein.l tu!6.
ls the fuse OK?
Turn the ignition switch ON.
Disconnect the 3P connector oteach sensor one al a time:. MAP sensor. TP sensor
Rcplaoo thg lgnlor that caur6dth. llght to Oo out.Does the MIL remain ON?
Turn the ignition switch OFF.
connect the test harness.Disconnect the "D" connectorfrom th€ ECM only, not the mainwire harness (see page 11-37).
Check tor continuity betweenbody ground and D19, O2O ter-minals,
- Bapai? rhod ro body g.ound inYEL/WHT wi.e boiwoon ECM(Dl9) .nd MAP ..n3or.- R.p!k shon to body ground inYEL/BLU wire b.lwo6n ECM(O2Ol .nd TP 3on!or.
Reconnect all tho sensor con-necrors,Reconnect the "D" connector torhe ECM.
Turn the ignition switch ON.
{To page 11-45}
System
Control Module (ECMI (cont'dl
PGM-FI
Engine
Dt9I
I oooooooooo ooo I oooooooo I omoool o oooooooooo | |I ooooooooooooo I oooooooo 1o('oe(lo I ooooooooooo | |-lD2O I
\-.J
Continuity?
(From page 11-43)
Disconnect "A" con-nector from the ECM.
Subrtltute r knowngood ECM.nd rochock. ll lymptom/indics-tlon g@a rw!y, rephco tho origi-n.l ECM.
ls the MIL ON?
Ropair short to bodygiound in GRN/ORNwir6 botwoon tho ECMlA131 6nd MlL.
11-44

(From page 1l-44)
Measure voltage between 426
{- ) and the following: B'1 (+ } andA25 {+ t.
- Ropsir opon in YEL/BLK wirobotwoon ECM (425, 81l andPGM-FI m6in relay.- Chock PGM-FI main rclay andwiring connectors at PIGM-FImain.olay (soe psg6 11-1121.
ls there battery voltage?
Measure voltage between bodyground and the tollowing termi-nals individually: A23. A24, A26,42.
- noprir opon in BLK wit. b6-twson ECM 1A23, A24l andG'101 {locatod al th6.mostathousingl.Repair opon in BRN/BLK witebotweon ECM (A26, B2l andGl0r.
ls there less then 1.0 V?
Substitut6 r known{ood ECM
and r6chock. lf symptom/indica-tion goos away, roplaco tho origi-nal ECM.
BATTERYVOLTAGET
ooooooooooo
oooooooooooooooooooooo
ooooooooooo
oooooooo
ooooooo
L€ss than 1.0 V?
11-45

YES
PGM-FI
Heated
11-471
System
Oxygen Sensor Heater (cont'd)
YEL/BLK I+I ORI{/BLK (-I
wire side
HO2S44 N.m{4.5 kgt.m, 33 lbf.ft}
Check for continuity to bodyground on terminals 3 and 4of theHO2S.
Check for continuity between terminal4 and terminals 1 and 2 in-dividually.
Turn the ignition switch ON.
At the HO2S harness. measurevoltage between YEL/BLK 1f lteFminal and ORN/BLK l-) ter-mrnal.
Turn the ignition switch OFF.
Disconnect the "A" connectorfrom the ECM.Measure voltage between YEL/BLK l+) terminal and bodyground.
Turn the ignition switch ON.
At HO25 harness, measure vol-tage between YEL/8LK (+) termi-nal and ORN/BLK {-) terminal.
RoDair short in ORN/BLK wir6 b6tw6on ECM(A6l and HO2S.ls there baftery voltage?
Ropai. opon in YEL/BLKwire botwoan HO2S.nd PGM-FI main relav.
Turn the ignition switch OFF.Turn the ignition switch OFF.
11-48
{To page 11-49){To page 11-49}

{From page 11-56)
Measure resistance between ter-minals of the indicated sensor.'see table
R.olac6 th. distributorhousing (8oo aoction231.ls there 35O-7O0 0?
Check for continuity to bodyground on both terminals ot theindicated sensor,
Rgplace tho di.tributorhousing llo€ loction23t.
Connect the test harness to themain wire harness only, notto theECM (see page 1 1-371.
Measure resistance between ter-minals of the indicated sensor ontest harness.'see table
Roprir opon in tho indi-cated senaoa wirea.*soo tablols there 350 70O 0?
Repair short to bodyground in tho indicrl.dt€naor wiroa.i s€e tabla
SEIiSOFDTCSENSORECMTENMINAICOLOR
2815ATU/GFN
6816BTUTVEI
TDCa813ORN/BTU
814
9B1tORN
as12
o o ooooo oo ooo o I oooooooo l6coocl o oo ooo ooooo
o oooo ooooo ooo I oooo oooo lo{nofioo't oooooooo ooo
812350-7000?
Check for continuity to bodyground on 815. 813 and/or B'l 1terminals.
ls there continuity?
NO
Substituto a known-good ECMand rechock. lf symptom/indica-tion goes away. roplaco tho origi-n.l ECM.
11-57