1999 HONDA CIVIC Control arm

VTEC Control SYstem
The scan tool indicates Diagnostic Trouble Code {DTC) Pl259:
VTEC Solenoid Valve circuit
Refer to page 1'l-38 through 11 55 before troubleshooting
Troubleshooting Flowchart
YES
A problem in the WEC Pressure Switch circuit or
* Road Test:Accelerate in 1st gear to an engine speed over 6,000 rp '
Hold that engine speed for at leasttwo seconos'
lf the DTC P1259 is not repeated during the first road test'
repeat this test two more times
VTEC PRESSURE SWITCH 2P
CONNECTOR
Terminalside ofmale termtnals
WM
/1 IBLU/BLKI
/ 1 Y------rt--------- l I
\1-/ |I
I
I1
Wire side of femaleterminals
(cont'd)
6-51
The MIL has been teported on.
DTC P1259 is siored.
Check the VTEC Control SYsiem:
1. Do the engine control module(ECM ) Reset Procedure (see
section 11).
2. Start the engine
3. Warm uP the engine to normal
operating temPerature (cool
ing fan comes on).
4. Do the Road Test.*lntermittent failure, sYstem is OK
at this time.Check for Poor connectlons or
loose wires at VTEC Pressureswilch. VTEC aolenoid valvo and
ECM.
ls DTC P1259 indicated?
Test the VTEC Pressure Switch:
1. Turn the ignition switch OFF.
2. Disconnect the VTEC Pressure
switch 2P connector.
3. Check for continuity between
VTEC pressure switch 2P con
nector telminal No 1 and
No.2.
Reolace the VTEC Pre3sure switch.
Test the VTEC Pressure Switch
Wire:1. Turn the ignition switch ON (ll).
2. N4easure the voltage between
VTEC press u re switch 2P
connector No. 1 and bodyground,
Inspect lor an open or short toground in the wire between the
VTEC orassure swilch and ECM
{c101.lf the wire i3 OK, substitute a
known-good ECM and recheck.
{To page 6 52)

VTEC Control System
Troubleshooting Flowchart (cont,d)
VTEC PRESSURE SWITCH 2PCONNECTOR
Wire side of temaleterminals
OIL PRESSURE GAUGE(Comm.rcially avail.bte)
GAUGE JOINT ADAPTERSNAP.ON MT26.1710 x 1.0 ftm. Use new washer wheninstalling the sealing bott.
NOTE: Keep measuring time as shorr aspossible because engine is running witn noload lless than one minute).
6-52
(
VTEC SOLENOID VALVE lPCONNECTOF
Ir------r I
lLl.ll-r
II
It
Terminal side ofmale terminal
I
(From page 6-5l l
(To page 6-53)
Test tha VTEC P.es3uro SwitchWi.e:Measure voltage across the VTECpressure switch 2P connector.
Ropair opon in the wiro batwoenVIEC pr...urc switch and G lot .lf the wiro is OK, 3ubltitutr aknown-good ECM and rochack.
ls there battery voltage?
Test the VTEC Solenoid V.tve:1. Turn the ignition switch OFF.2. Disconnect the VTEC solenoidvalve 1P connector.3. Check for continuity betweenthe VTEC solenoid valve 1Pconnector terminal No, I andbody ground.
ls there 14 - 30 O?
Te3t the VTEC Sotonoid Vatve:'1. Remove the VTEC pressureswitch and install the specialtool as shown. then reinstallthe VTEC pressure switch.2. Reconnect the VTEC solenoidvalve 1P connector and VTECpressure switch 2P connector,3. Connect the tachometer (seesection 1l).4. Start the engine.5. Warm up engine to normaloperatrng temperature (cool-ing fan comes on).6. Check oil pressure at enginespeed of 1,000,3,000 and5,000 rpm.
ls pressure below 49 kPa(0.5 kgflcm,,7 psi)?Inipoct thg VTEC aolenoid valvel3ee P8go 6-54).
I

Troubleshooting
E n gine/P_o,weft ra in Control Module Term inal Arra n gement('96 - 98 Models, '99 - 00 Dl6yS engine with M/T)
-
ECM/PCM CONNECTOR A I32PI
1INJ62INJ3INJ21
INJl567I
LG110PGll1
IGPl12
ACV
131115
PCS
16
FLR17acc18MIL19ALTC20
tcM22PG221IGP2272A25
VSV30
SLU
ECM/PCM CONNECTOR A (32P)
'2: A./T (D16Y7, 016Y8 engine)13: CvT (D16Y5 enoin€)',4: A/T and D16y7 engine*5: Except A/T and D16Y7 €nsine'6r A/T (D16Y8 ensine)'7 Cw 1D16Y5 eng,nel and D16y8 ensrne'"'3:Bi..I?'Jt;".'e'.!ti.?i?l'""."T8"_";btfr
"fl
1-88
Wire side of female terminals
NOTE:Standard battery voltage12ts
'10i i,4/T (D16V5 engine)r11 Ex.ept M/l (D16V5 enqinelr12: 016Y5, D16YB enqine
r15:'97 016Y7 engine lcoupe: KL modet, sedan: KL (LXl modet),'98 D16Y7 engine
1
1
Sign.l
YELlNJ4 (No.4 FUEL INJECIOB)D ves No 4 ruel injector.Wilh engine runninq: ddly coniroted2BLUlNJ3 lNo. 3 FUEL TNJECTOBJDrives No. 3 lue Inteclor.38EDINJ2 (NO, 2 FUEI INJECTON)Drives No. 2 iuel njector.88NlNJl (No. 1 FUEL INJECTOB)Dives No. 1 ruelinjector.
5SO2SIITC (SECONDAFY HEATEDOXYGEN SENSOF HEATEF CONTFOL)
Orives secondary heated oxyqen sensorWith ignilion switch ON (lll: batery vo lageWith f!llywarmed up engine runninq:dLtv controled
6BLXAVHTPO2SHTC (PRIMAFY HEATEOOXYGEN SENSOR HEATERCONTROL)
Drives prihary healed oxygen sensorWith ignition switch ON ltt):baneryvottasewlhrdllywdrmedupcngne,Lnnrrq dury,orl.otred
FED{ESOL (EGF CONTRO!SOIENOIO VALVE)Drives EGF conlrolsoleno d vatve.Wilh EGR operating during drving wiih fu|y warmedup engrne: duty controttedWilh EGF nol opefating:O VE.EGRWith EGF operating du.ing driv og wilh iuty warmedup en9ine: dutycont.olted.With EGR not ooeralino; o V8*r/GFN/YELWS (VTEC SOLENOTD VALVE)Drives VTEC solenoid va veWilh eng ne at ow engine speed:O VWirh engine at h gh enqine speedr banery vohaae9BflN/BLKLG1 (LOGIC GROUND)Gro!nd lorthe €CM/PCM conlrotc rcuit.Lesslhan 1.0 V at a ttimest0ALKPG1 IPOWEF GFOUND)Ground ior rhe ECM/PCM power.tcuf.11YEVBLKIGPT iPOWEF SOUFCE)Power source forthe Ec[,l/PcM conlroWilh ignition swirch ON (tt): battery voltageWith gntron switch OFF: 0 VBLVBLUIACV (IDLE AIN CONTROL VALVE)Wilh engine r!nn ng: dlty contro ed13,.o8NIACV N lIDLE AI8 CONTFOLVALVE NEGATIVE SIOE)Drivesthe IAC valve {negalive side).
BLVBLUIACV P (IDLE AI8 CQNTROLVALVE POSITIVE SIDE)Orives IAC vaive (posilive side).
FEO/YELPCS (EVAP PURGE CONTFOTSOIENOIOVALVE)Drives EVAP pu.ge controtsolenoid vatve.Wilh engioe running, engin€ cootani betow 154,F'68'Cr bancry vohaSe w'ln ens nc runn,.o. eng,rc
GRN/YELFL8 (FUEL PU[4P FELAY)Orives fuelpump relay.0 V {or two secor os ahe' tJ n ng 'onir or \wnch ON ,,,,,
I7BLI(REOACC (A,/C CLUTCH RELAY)Drives A/C clutch relay.Wirh compressor ONr0 VWilh compressof OFF:banery votrage18GFN/ONNMIL (I\,lALFUNCTION INDICATOFWith MIL lLrned ON: 0 VWith illl turned OFF: banery volaqe19',AITC {AITERNAIOR CONIROL)se.ds ahernator controt signat.Wirh fully warmed.up engine ru.ntng: battery votlas€During drivins wnh smatl eteclricat toad: O V
20YEVGRNICM (IGNI'TION CONTROLMOOU!E)with ignltlon swilch ON (tl):b6n€ry vohageWilh ensine runnins: aboul t0 V (depending on
22BRN/BLKLG2 (LOGIC GAOUND)Ground for the ECM,/PCM conrrot ci'cu LLess than 1.0 V at a tt mes23BLKPG2 iPOWEA GROUND)Gro!nd lor the ECM/PCM power circuir.24YEUBLKlGP2 (POW€R SOUSCE)Power sou.ce lor the ECM/PCl, conrrolWnh ignilion swilch ON {it):battery vohageWilh ignilion switch OFF:0 V25*6WHT/FEDVSEF IREFEfl ENCE VOLTAGE)Provrdes reference voIaOe to TCM.With ignition switch ON (tt):abour 5 VWth gnition swltch OFF: O V21'1GFNFANC {RAOIATOR FANCONTFOL)Drives radialof fan ielay.With radialor fan f!nn nqr O VWilh radiato.tan stopped: batteryBL!2WBS (EVAP BYPASSSOLENOIO VALVE]Orives EVAP bypass sotenotd va !e.With ignirion swrrch ON (tt):barery vo rase
LT GRNA/VHTVSV (EVAP CONTFOTCANISTEFVENT SHUT VAIVE)Drives EVAP conlfot canisrer venl shulwnh ignirion sw'tch ON lr|l barery volaqe
WHT/NEDSLU (INTEFLOCK CONTFOLUNIT)Detects intenock conlrotLn t signalWhh ignition switch ON (tt)and brake pedadepf essed: battery vollage

Troubleshooting
Engine/P_o_wgrtrain Control Module Terminal Arrangement('96 - 98 Models '99 - 00 Dt6y5 engine with M/T) tc'oniOi
ECM/PCM CONNECTOR C {31PI
1
CKFP
2
CXPPTDCPa
ACS
5
sTs
7
scsII
rMA
10
v8u121314t51517
ALTF
TE
vss23lP+
21252930
TMA
Wire side of female terminalsECM/PCM CONNECTOR C (31PI
NOTE: Standard baftery voltage is 12 V
'1: USA modelr2rA,.T (D16Y7, O16Y8 ensane)*3: CVT (O16Y5 engine)*4: Ay'T and O16Y7 engine'5: Excepl A./T snd Dl6Y7 engine16: Ay'T (D16Y8 ensine){7: CVT (Dl6Y5 eosine) and O16Y8 enoine"8: 96 Dl6Y8 engine (coupe),'97 D16y8 engine (coupe: atl:ed-9I t!!rnodelr,'98 D16y5 ensine,,98 D16y8 e;sine.D16Y5 lM/T) ensine
1-90
19: D16Y5 engine'10: M/T (Dl6Y5 engine)*11r Except M/T 116Y5 engine)*12: D16Y5, D16Y8 engine*13: Dl6Y8 enqine*14: O16Y7 enginei15: '-97 O16Y7 engjne (coupe: KL modet, sedan: KL (LX) modet),'98D16Y7 enqine'99 - 00
1
To.min!lnumberWiracoloaTorminalnameDo6criptlonSignal
1BLU/REDCKFP (CKF SENSOR P SIDE)Detects CKF sensor.With engine running: pulses2BLUCKPP (CKP SENSOF PSIDE)Detects CKP sensor.With engine running: pulses3GRNTDCP {TDC SENSOR PSIDE}Detects TDC sensor,With engine running: putses4YELCYPP (CYP SENSOR P SIDE)Detects CYP sensor.With engine running: pulses
5BLU/FEDACS {Tr'C SWITCH SIGNAL)Detects ,ay'C sw;tch signat.With Iy'C switch ONr 0 VWith Ay'C switch OFF: batrery vottage
6BLU/ORNSTS (STARTER SWITCHSIGNAL)Detects staner swilch signal,With staner switch ON ltlt): batery vohageWith staner switch OFF: 0 V
8RNSCS (SERVICE CHECKSIGNAL)Detects service check connector signal{the signalcausing a OTC indicationlWith the connector connected: O Vwith the connector disconnected: about 5 vor battery voltageLT 8LUK,LINE (DLC)Sends and receives scan iool signal,Wirh ignition switch ON { ): about 5 V
9+3GRYDat6 communication with TCM: ECMcontrol ctat6 outputWith ignition switch ON (tt):putses
10WHT/BLUVBU (VOLTAGE BACK UP)Power source forthe ECM/PCMcontrol circuit. Power sourc€ lortheDTC memory
Battery voltage at all times
11WHT/REDCKFM {CKF SENSOR MSIDE)Ground tor CKF sensor signal.
12CKPM (CKP SENSOR MSIDE)Ground for CKP sensor s;gnat.
REDTDCI\4 (TDC SENSOR MSIDE)Ground for TDC sensor signal.
14BLKCYPM (CKP SENSOB MSIDE}Groond for CYP sensor signal.
15."BLU/BLKVTM (VTEC PRESSUREswtTcH)Oetscts VTEC pressure switch signal.Wrth engine at low enginespeed:0 VWth engineathigh engine speed: tatteryvoltase
16GRN
PSPSW (P/S OIL PRESSUREswtTcH)Detects PSP switch signal.At idle with steering wheel in straight aheadposition:0 VAt idle with stsering wheet at fult tock batteryvoltage'17WHT/REDALTF (ALTERNATOR FRSIGNAL)Detects ahernator FR signal.With fullyw6rmed up engine running:0 V- bat-teryvohage (depending on electricat toad)18BLUI/VHTVSS {VEHICLE SPEED SEN-SOR}Oetects VSS signal.Whh ignitjon switch ON {tt) and front wheetsrotating: cycles 0 V- 5 V23+14BLKlP+ {HO2S PUtr4P CELL +}Controls HO2S pump ce .With ignition switch ON (ll): abour 0.5 - 5.3 V
24.10REDrP-, vs- {Ho2s coMt oN)Reference voltage supply.With fullywarmed up engine et idle:about2.6-2.8 V25*roVS+ (VS CELL VOLTAGE)Detects VS cell voltage.With ignition switch ON t): abour 7 V
29LT GRN*'ATPNP (Ar'T GEAR POSI,TroN swrTcH)Deteds Ay'T g6srposhion switch signat.In E orE position: O Vln any other position: battery vottage
RED{roCLSW (CLUTCH SWITCH}Detects clutch switch signal,Wilh clutch pedal released: about 5 VWith clutch pedal deDressed: O V30PNK4TMBData communication with TCM:ECM controldata inputWith ignit;on switch ON (lt):putses

Troubleshooting
Engine/P_o,wertrain Control Module Terminal Arrangement('99 - 00 Models except Dl6Y5 engine with M/Tl
ECM/PCM CONNECTOR A (32P)Wire side ot temale terminalsNOTE:Standard battery voltage is l2 V
ECM/PCM CONNECTOR A I32PI
Sign!l
3BLU2WSS (EVAP 8YPAsS SOLENOIDDrives EVAP bypass solenoid vatve,With gn'tion swnch ON (lll banery votlage
LT GRN/I/VIITVSV {EVAP CONTNOL CANISTERVENTSHUTVALVE]Drives EVAP controt ca n isrer v€nt shutWilh ignilion switch ON {tl): b€ttery vottage
8LU/GNNC8S (CRUISE CONTSOL SIGOown shift signal inpot lrom c.uise conrrolWhen crurss control is used:purses
68ED/YELPCS {EVAP PURGE CONTROLSOTENOIOVALVE)Drives EVAP purge conrrol sotenoid vatve.With engine running, engine cootant, betow r54.F (6a,C):
With engine.unning, €ngine coolant, abov€ 154.F(68'C): duty conlrolled
YELATPD {AT GEAR POSITIONSWITCH)ootects A/T gear posnion swilch s,gnar.In otherthan @ posilion: Apprcx. 5 V
8BLK,IflHTSO2SHTC (SECONDARY HEATED OXYGEN SENSOS HEATEFCONTFOL)
Drives sscondary h€ared oxygen senso.Wilh isn,rion swirch ON (ll):banery votraseWith lully warm6d dp€ngire runn'ng:dury controled
LT GRNATPNP (AT GEAF POSITIONSWITCH)oereds A/T 9€a r position switch signat.In Parr or neulrsl:0 VIn anyother position approx.5 v
t088NSCS (SERVICE CHECK SIGNAL)Oetects ssruice check connecror signal(the signalcausing a OTC indication)with rh€ t6rminal connected: 0 vWith the rerm ina I disconneded: abour 5 V of ban€ry
GNN/BIKD4IND (D4INDICATON]Drives Oa indicaio. lighr.With D4 indicator lightturned ON: O VWith D4 indicator lightturned OFF: battery vo ttageG8N/YETFTF (FUEL PUI\,4P SELAY)Orivos tuel pump relay,0V for two s€conds lfrer turnrng rgnilior swtcn ON(ll), then batt€ry voltage11BTI(REDACC (Al/C CTUTCH SELAY)Drives A./C clutch reray.With compressor ON:O VWilh comp.ssor OFF; battery vottage18GFN/OFNMI! (A,IAIFUNCTION INDICA.TOF LIGHT)With MlLturned ON:0 VWith l\,llL tornod OFF|batrery votrsge198tuNEP (ENGINE SPEED PUTSEIOulputs6ngine speed pulse,Wilh engin6.unning: putses
20GFNFANC {SADIATOR FAN CONTnoL)Orives radiarortan relay.Wirh r.distor t6n running:OVWith radiatortan stopped: banery vottage21ELUA/ELK LINESends and r€ceives s.an lool signal.With ignition switch ON (ll):p!ts€s
22'lBLUATP L {AT GEAS POSITIONswtTcH)Oelocis A"/T gear posirion switch siSnat.In othfflhan E position: Apprcx. 5 V
23SHO25 (SECONOARY HEATEDOXYCEN SENSOR, SENSOF 2)Detects secondsry hoar€d oxygen sensorWith lhronle f! lly or'6ned from idte with fu ywarmod up engine: above 0.6 vWiih th.onl6 quickb, closd:below 0,4 V24STS ISTAFTEN SWITCH SIGDebcrs staner switch signat.Wirh srarterswitch ON (tttJ: batteryvottogeWith sraftsr cwirch OFF:0 V26GFNPSPSW iPlS PNESSURESWITCII SIGNAL)Derecrs PSP switch signat.Atidle with steoring wheolin srraightahead position: O VAt idl6with steering wheetal fult lock: barery vo ttags27BLU/REOACS (AJC SWITCH SIGNALJOer*ts ,ay'C swirch signat.Wiih ty'C switch ON;0VWilh Ay'C switch OFF|aboor 5VWHT/REDSLU iINTERLOCK CONTROIUNIT)Drivos interloct control unit.With ignltion switch ON (ll)and brake pedaldepresed: batlory volrage29LT GRNPTANK (FUEL TANK PFESSUEESENSOR)Oer6ds lu€l tank pr€ssura sonsor signat.Wilh ig.rrrd swirch ON rttr and fuetti

cap ooen6d.
30GRN/FEOEr (ELOIWith parking lighlsrurned on ar idteiaboui 2.5- 3.S VWirh low beam he€dlig hts turnqd on ai idts: aboul 1.52.5 V32GRN/'WHTAKSW (BFAKE SWITCH)Detets brak€ swrtch signEt,With brake pedal r6l€ased:0 VWhh brake pedaldepres*d: battery voltEse'1:A./T (D16Y7, D16Y8 engine)*2: rvt/T13: CVT (D16Y5 engine)
11-92

ECM/PCM CONNECTOR B (25PI
Wire side of female terminals
FCM CONNECTOR B {25P)NOTE: Standard battery voltage is 12 V
Sign.l
YELtsLKIGP1 IPOWER SOUflCE)Powor sou rca for the ECM/PCM conlrolcirwhh ignilion swilch ON (ll)ibatteryvoltageWith ignition switch OFF:0 V
BLKPGl {POWEB GNOUND)Ground fo. the ECM,/PCM contrclcncuit'Less than 1.0 V at slltimes
FEDlNJ2 (No 2 FUEL INJECIOR)Drives No. 2 fu€l inieclor'Wirh enqine runnin9: dulv conlroll6d
BLUlNJ3 (No.3 FUEL INJECTOB)Orives No.3 fuel inieclor'
YELlNJ,r lNo. 4 FUEL INJECTOF)Drives No. 4 luel injector'
6BLI(BIUIACV P (IDLE AIR CONTROLVAIVE POSITIVE SIDE)O.iv€s IAC valve {Posirivo side)Wilh engine running: duty conrrollod
BEDESOL {EG8 CONTROLSOLENOID VALVE)Drives EGF controlsolonoid valveWith EGR operaiing during driving wirh follv warmedup onginsl dutY controlledWilh EGR nol op€r.ring:0 V
PNKSLKHlC tstvr (PH-PL CONTnOLLINEAfl SOLENOID NEGATIVEst0E)
G rcund for PH-PL control linsar solsnoid
8.,LS - (A/T CLUTCH PFESSURECONTROL SOTENOIDVALVE'sroE)
A/Tclutch prsssure conrrol sol€nod valv€pow6r slpply negative elecrodeWith ignilion swirch ON (ll):dutv controll€d
9YEUBLKrGP2 {POWE8 SOUFCE)Powor $urce for lhe ECI{,'PCM controlc'rcuitwnh ignirion swirch ON (ll): ban€ry voltag€with ignirion swnch oFF:0 v
10BLKPG2IPOWER GSOUNDIGround lor ths ECM/PCM controlctrcuil
118RNINJl {No,1 FUEL INJEqIOR)orives No. r ru6l Iniocror.With onsino at low lpm:0Vwith ens,n. ar hish tpm:bsneryl9!9gl-12"GRN,.YELWS (WEC SOLENOID VALVE)Orivos WEC solanoid v.lvs.
13YEUGRNICM {I6NITION CONTROL MODULE}
With ignition switch ON (ll)r b5n6ry volt€gsWilh engino running: Puls6
15ORNIACV N (IDLE AIN CONTSOIVALVE NEGATIVE SIOE)Drivos the IAC valve lnogativ€ 3idelWith €ngin€ ru nningi dr]tv controlled
REDLS + (A,/T CIUICH PRESSURECONTFOT SOIENOIOVALVE +SIDE}
A/T clutch pr€so.6 controlsolenoid valvepow6r slpply posiliv€ oroclrodeWirh ignition swatch ON (lll: dutYcontrorled
HLC LSP (PH-PI CONTROI LIN.EA8 SOLENOID POSITIVE SIDE)Orives PH-PL control line€r solenoidWith qnition switch ON (lll: Pulsing srgnal
PNK/BTUSC LSM (STAfiT CLUTCHLINEAR SOLENOIO N€GATIVESIDE)
Groundforstartclutchcontrol line6r
20BnN/AtKLGI (LOGIC GEOUNO)Ground for lh€ EcM/PcM controlcircuit'L6se rhan 1.0 v.i alltimes
21VBU IVOLTAGE 8AC( UP)Powet source torlhe ECM/PCM control circuitPower sourco tor th6 DTC m€mory'Battaryvoltage aitnEtrmes
22BFN/8IKLG2 (LOGIC GSOUND)Ground iorths ECMnCM conrrol circuir'tsss thah 1.0 v al all times
238LI(BLUIACV (IOTE AIR CONTROLWitn ongine funning: dutv conrol!6d
25'3YELSC LSP {STANT CLUTCH LINEARsotENorD PoSlrlvE slDE)Orives sran clutch control linesr solonoid.With ignilion swilch ON (ll): Pulsing sign3r
r1: A/r (D16 , D16Y8 ensins)
'3:CVT {O16Y5ensino)
'4: Ol6Y5, Dl6Y8, B164? onsina
(cont'd)
1 1-93

Troubleshooting
Eng ine/P_owertrain Control Module Term inal Arrangement
('99 - 00 Models except Dl6Y5 engine with M/Tl (cont,d)
ECM/PCM CONNECTOR C {31P)Wire side of female terminalsNOTE;Standard
*1;4"/T lD16Y7, D16Y8 ensinel
43: CVI(016Y5 engine)'4: D16Y5, D16Y8, 81642 engin€
ECM/FCM CONNECTOR C 13lPI
is 12 V.
Sig.al
lBLK4/VHTPO2SHTC (PNIMARY HEATEOOXYGEN SENSOB HEATES CONTROL)
Drivss primary hoated orygen sensofWith ignition switch ON (lr)rbanery volageWrh fJly warned up €ngir. ru..i19: duty.oaro ed
2WHT/GFNALTC (ALTESNATOB CONTSOL)Sends aliernalo. control sig nal,With fullywa.med upengine ronning; banery vohaseDuring d.iving with smallelect.icatioad; O V38ED/BLUK5 (KNOCK SENSOR)with sngine knocking: pulses
5WHT/REDATTF {AITEFNATOR FR SIGNAL'Detects slternaror FR si9n.l.With tullywarmed up engine running:O V- batteryvortage(dependingon erectficat toad)
WHT/8LKEGRL (EGN VAIVE LIFTSENSOR)Dete.ts EGR valve lrft sensorsignat.
GRN,4r'l/flTSGl ISENSOE GBOUND)Groond fo. MAP s€nsor.L€ss rhan 1.0 v at alltimes88luCKPP (CKP SENSOR P SIOE'With engine running: pulses9CKPM {CKP SENSOR M SIDEIGround for CKP sensor.
BLU/BLKwlvl (wEc PREssuSE swtTcllSIGNAI)D€tocts VTEC pfessure switch signat,With €ngine at low enginospeed:0VWith engin€ at high engino speed : banery vo ttaae
16PHO25 (PRII\,1AFY HEATEDOXYGEN SENSOR, SENSOR 1)Oetects primary heated oxygen s6nsor lsen-With lhrottle f!l1y open€d from idtewith tuly,wa.med !p engin€: Ebove 0.6 VWilh thronl€ quickly closed: b€tow 0.4 V
FED/GRNMAP (I\,4ANIFOLD ASSOLUIEPFESSUSE SENSOB}Dotocrs i,4AP sensor signsl.With ignitioh switch ON (ll):about 3 VAt idlei6boul 1.0 V (depending on engine speed)18GBN/8LKSG2 (SENSOR GSOUND)Less than 1.0 V aralttimes'19YEUNEDVCCl (SENSOR VOLTAGEIPowersourcero MAPsenso..With ignition swilch ON {ll):about 5 VWirh iqnition switch OFF]0 V20GNNIDCP (TDC SENSOB P SIDEIWith ongine running: pulses218EDTDCI\,I (TDC SENSOR M SIOE)Ground lor TOC aensor.22BTU/NEDCKFP (CKF SENSOR P SIDE)With engine running: p!lses
23VSS {VEHIClE SPEED SENSOR)Wilh ignrt|on swich ON rllr snd lront wl-ee' rotating.cycles 0 V about 5V or baneryvottage
25BED/YELIAT ONTAKE AIF TEi,4PEBA.TUEE SENSOR)Detects IAT senso. signat.With ignition switch ON (ll): about 0.1 4.8 Vldepending on i.take air ternpe.atu re)
268ED,ryVHTECT (ENGINE COOLANTTEI\,I.PESATUBE SENSOR)Oelects ECT sensor signal.With ignirion swirch ON {ll):about0.1 -4.8 V(depending on engine coolant temperatu re)
21NED/BLKTPS (THROTTLE POSITION SEN,SOF)Detects TP sensor signal.Wilh th.onle fully op€n: about 4.a VWith rhronle f!lly closed: about 0.5 V
2aYEVBLUVCC2 (SENSOR VOLTAGE)Provides s6nsor voltag€.With ignirion swirch ON (tt):about 5VWith ignilion swiich OFF:0 V29YELCYPP (CYP SENSOR P SIDE)Wilh €ngrne running: pruses3oBLKCYPM (CYP SENSOR M SIDE]G,ound for CYP sonsor.J1WHT/FEDCKFM (CKF SENSOB M SIDE)Ground fo. CKF sonsorsign6i.
11-94

ldle Control System
ldle Air Control (lACl Vatve ('96 - 98 Dl6ys, Dl6yB engine with M/Tl
The scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt flAC) varvecircuit.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR ICl3A)
,flrcerh-:J iYEL/BLKI
!.__-,/ -lt(v)
-T-=
Wire side of female terminals
tAcv(BLK/
ELUI
ECM CONNECTOR A I32PI
Wire side oI lemal€ terminals
VALVE
6a10ll12t3r5t6l7t8t920232a
t*25&a2A3o
The MIL hss b€on repo.ted on.DTC P'l508 i. itorod.
Problem vorification:1. Do the ECM/PCM Reset Pro-cedure,Start the engine, and warm ituP to normal operating tem-perature.
Intormittont t!llur., sy.tcm b OKat thb tim6. Chsck fol poor con-ncctionr or loo3e wirot at C138(lAC valv.l.nd ECM.
ls DTC P1508 indicated?
Check for an opcn in the wiro(lGPl line):1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure vohage between bodyground and the IAC valve 2Pconnectorterminal No. 2.
R.prir opan in the wiro botwa.nIAC valv..nd PGM-FI main r.l.y.
Chock for an opon or sho in thewire (IACV linal:1. Turn the ignition switch OFFand reconnect the IAC valveconnector.2. Disconnect the ECM connectorA (32P).
3. Turn the ignit;on switch ON (ll).4. Measure voltage betweenbody ground and ECM con-nector terminal A12.
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