Page 286 of 1395
Powertrain Control Module (PCM) -'97 Model (cont'dl
(From page 11 83)
Check for a short in the wire (MlL
line):1. Turn the ignition switch OFF.2. Disconnect the PCM connectorA {32P).3. Turn the ignition switch ON (ll).
Repair short to body ground inthe wire between the PCM {418}and MlL.ls the MIL ON?
Substitute a known-good PCMand recheck. lf symptom/indica-tion goes away. replace the origi-nal PCM.
Inspect Fl E/M (15 A) fuse in theundeFhood fuse/relay box.
- Reoair shod in the wirebetween Fl E/M {15 A} fuseand PGM-FI main relav.- Replace FIE/M 115 A)fuse.
Inspect No. 13 FUEL PUMP (15 Aifuse in the underdash fuse/relay
- Repair short in lh€ wirebolween No. 13 FUEL PUMP
115 A) Iuse and PGM-FI main
- Replace No. 13 FUEL PUMP
115 A) fuse.
Check loJ a short in a sensor:1. Turn the ignit;on switch ON (ll).
2. Disconnect the 3P connectorof each sensor one at time:. MAP sensor
(To page 11-85)
11-84
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Page 287 of 1395
(From page 11-84)
Reolace the Sensor that causedthe lighl lo go out.Does the MIL go off.,
Check for a short in the wires
lvCC linesl:1. Turn the ignition switch oFF.2. Disconnect the PCM connector D (16P).
3. Check for continuity betweenbody ground and PCM connector terminals D4 and Dl0 individually.
Repair shorl lo body ground
in the wile between the PCM
{D4} and the MAP sensor.Repair short to body ground inth€ wire between the PCMlol0l and the TP sensor.
Check tor an open in the wires
llGP line3l:1. Disconnect the fuel injectorconnectors and IAC valve con
2. Turn the ignition switch ON (lli.
3. [,4easure voltage betweenbody ground and PCM con'nector terminals A'11 and A24individually.- Repair open in the wire(slboiween the PCM 1A11, A24)and the PGM-Fl main relav.- Ch€ck lor poor connectionsor loose wires at ihe PGM-FImain relay.- Tesi lhe PGM-FI main relav
{see p.g6 1l-1871.Check for an open in the wires
{LG linesl:1. Turn the ignition switch OFF.2, Reconnect all sensor connec-tors,3. Reconnect the PCM connectorD (16P).
4. Turn the ignition switch ON (ll).
5, M easu re voltage betweenbody ground and PCM connector terminals Ag a^d 422individually.
R6pair open in the wire{slbetween the PCM {A9. A22l andG101 {located at the thetmostathousing) that had more than 1.0 V.
ls there less than 1.0 V?
Substituto a known-good PCMand rech€ck. It symptom/indica-tion goos away, replace the origi-nal PCM.
PCM CONNECTOR D (16PI
VCCl NEL/RED}
Wire side of female terminals
PCM CONNECTOR A (32PI
Wire side of lemale terminals
1 1-85
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Page 288 of 1395
PGM-FI System
Tho Maltunction Indicator Lamo(MlL) n6Yor como3 on leven lortwo laconds) rft6r tho ignhion isturnod ON {lll.
Turn th6 ignition switch ON (ll).
- Repair lhort or opcn in thowire between the No. 25METER 17.5 Al fu3e snd thegauge assembly.- Repl.co the No. 25 METER17.5 Al fus€.
ls the low oil pressure light on?
Try to start the engine.
Chock for an opsn in th€ wiro orbulb {MlL line,:1. Turn the ignition switch OFF.2. Connect the ECM/PCM con-nector terminal A18 to bodyground with a iumper wire.3. Turn the ignition switch ON (ll).
Rep.ir open in the wi.osbotween the ECM/FCM lA18land the gaugo rasombly.Roplece the MIL bulb.
ls th6 MIL on?
Substitute a known-good ECM/PCM and rochock. lf rymptom/indication goes eway, replacetho o gind ECM/PCM.
Turn the ignition switch OFF.Inspect the Fl E/M 115 A) tusein the undeFhood fuse/relaybox.
- Repair short in the wirebetween lhe Fl E/M (15 AlfusG and the PGM-Fl m.in.slay.- Roplsce th€ Fl E/M (15 Alfu3€.
Inspect the No. 13 FUEL PUMP(15 A) fuse in the under-dashfuse/relay box.
- Repair short in th6 wirebetween tho No. 13 FUELPUMP 115 A) luse and thePGM-FI main .elay.- ReDlace tho No. 13 FUELPUMP 115 Al tuse.
Engine Gontrol Module/Powertrain Control Module (ECM/PCM) -'98 - 00 Models
NOTE:. lf this symptom is intermittent, check tor:- A loose Fl E/M {15 A) fuse in the under-hood fuse/relay box- A loose No. 25 METER {7.5 A) fuse in the under-dash fuse/relay box- A loose No. 13 FUEL PUMP (15 Alfuse in the underdash fuse/rolay box- An intermiftent short in the wire between the ECM/PCM (A18) and the gauge assem-
- An int€rmiftent short in the wire between the ECM/PCM (C19) and the MAP sensor- An intermiftent short in the wire between rhe ECM/PCM (C28), the TP sensor, theEGR valve lift sensor and/or {uel tank Dressure sensor- A laulty PGM-FI main relay
ECM/PCM CONNECTOR A (32P}
Wire side of female terminals
(To page 11-871
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Page 343 of 1395
38 - 00 modeb:
Problem verification:1. Do the ECM/PCM Reset Proceoure.2. Stan the engine.3- Turn on the headlights.Intermittent feilure, sysl.m is OKat this time. Check for ooor con-nections or loose wires at C354(ELDI and at the ECM/PCM.
ls DTC P1298 indicated?
Check lor an open in the wire(lG1 line):'1. Turn the ignition and head-lights OFF.2. Disconnect the ELD 3P connector.3. Turn the ignition switch ON (ll).
4, Measu re voltage betweenbody ground and the ELD 3Pconnector terminal No. '1.Reprir open or short in th6 wirebotweon the No. 15 ALTERNA-TOR SP SENSOR {7.5 Al fuse inthe under-drah fuse/relay boxand the ELD.
Check tor an opon in tho wire{GND line}:1. Turn the ignition switch andheadlights OFF.2. Disconnect the ELD 3P connector.3. Check for continuity betweenbody ground and the ELD 3Pconnector terminal No. 2,
Repair opon in the wire betweenthe ELD conneclor and GilO2.
Ched( fo. an op€n in the wir€ (EL linel:Check for continuity between theELD 3P connector terminal No. 3and ECM/PCM connector termi-nalA30.
Repair op€n in tha wile botwecnthe EcM/PCM lA30l .nd rhe ELD.
Check for s malfunction in lhe ELD:1. Reconnect the ELD 3P con-nector.2. Start the engine and allow itto idle.3. While measuring voltagebetween ECM/PCM connectorterminals A30 and 820, turnthe headlights on (low).
Substiiute a known-good ECM/PCM and recheck. It symptom/indication goos away, replacethe original ECM/PCM.
ELO 3P CONNECTOR {c35/rl
Wire side of female terminals
Wire side of female terminals
Wire side ot temale terminals
ELD 3P CONNECTOR {C35,lt
EL IGRN/RED}Wire side of femaletermrnars
ECM/PCM CONNECTORS
A l32P)
11-141
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Page 351 of 1395
ldle Control System
System Description
The idle speed of the engjne is controlled by the ldle Air Control (lAC) Valve'
The valve changes the amount of air bypassing into the intake manifold in response to electric current controlled by the
ECM/PCM. When the lAc valve is activated, the valve opens to maintain the proper idle speed.
YEL/ From PGM'FI
BLK TMAIN RELAY
VARIOUSSENSORS
4.
IAC VALVE
INTAKE MANIFOLD
After the engine starts, the IAC valve opens for a certain time. The amount of air is increased to raise the idle speed
about 150 - 300 rpm.
when the cootant temperature ts row, the lAc valve is opened to obtain the proper fast idle speed The amount o{
bvoassed air is thus controlled in relation to the engine coolant temperature
When the idle speed is out o{ specification and the scan tool does not indicate Diagnostic Trouble Code (DTC) P0505
or P1508, check the following items:
. Adjust the idle speed (see page 11-169, 170)
. Air conditioning signal (seepagell-1551
. ALT FR signal (see page 1l-159)
. Starter switch signal (see page 11-16'1)
. A,/T gear position signal (see section 14)
. PSP switch signal (seepagell-162)
. Brake switch signal (see page 11-165)
. Fast idlethermovalve (see page'11 168)
. Hoses and connecttons. IAC valve and its mounting O-rings
lf the above items are normat, suDslitute a known-good IAC valve and readjust the idle speed {see page 11-169, 170)
lf the idle speed still cannot be adjusted to specification (and the scan tool does not indicate DTC P0505 or Pl508)
after IAC valve reolacement, substitute a known-good ECM/PCM and recheck lf symptom goes away' replace the
original ECM/PCM.
11-149
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Page 358 of 1395
ldle Gontrol System
Air Conditioning Signal (cont'dl
(From page 11-'155)
JUMPERWIRE
UNOER.HOOD FUSE/RELAYBOX 9P CONNECTOR tqt52)
123I
56I
ACC IBLK/RWire side ofACC IBLK/REDIWire side of femaletermrnats
A t32PlPCM CONNECTORS C t3rp)
Wire side ol lemale terminals
Ch6ck for an open in th€ wire(ACC linel:Momentarily connect the under-hood fuse/relay box 9P connectorterminal No.5 to body groundwith a jumper wire several times.
ls there a cl;cking noise fromthe 4!/C compressor clutch?
ls there a clicking noise fromthe 4!/C compressor clutch?See air condiiioner inspection{see section 221.
Repai. op6n in the wire betwoenthe PcM (A17) and tho A/Cclutch relay.
Check the A/C operation:1. Start the engine.2. Turn the blower switch ON.3. Turn the A"/C switch ON.
Check for an open in the wire(ACS line):Measure voltage between PCMconnector terminals Ag and C5.
Does the A,/C operate?
Air conditioning signal is OK.
Repair open in the wire betweenthe PCM lCSl and the A/C awitch.ls there less than 1.0 V?
- Subqtitute a known-good FCM.nd r€ch6ck. lt 3ymptom/indi-cation goes awav, replece theoriginal rcM.- Soe th€ eir conditioner in3pec-tion (s6€ aec.tion 22).
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Page 360 of 1395
ldle Control System
Air Gonditioning Signal (cont'd)
JUMPERWIRE
UNDER-HOOD FUSE/RELAYBOX 9P CONNECTOR {G'52I
23a
5589
ACC (BLK/R
Wire side otACC (BLK/RED'
Wire side otfemaleterminals
ECM/PCM CONNECTORS
Wire sid€ of female torminals
(From page '11,157)
Check Ior dn opon in the wiroIACC linel:Momentarily connect the under-hood fuse/relay box 9P connectorterminal No. 5 to body groundwith a jumper wire several times.
ls there a clicking noise lromthe y'y'C compressor clutch?
ls there a clicking noise fromtho A,/C comprossor clutch?Sae rir conditional in3pactionlroa saction 221.
Repai. open in th6 wiro lr€twlanthe ECM/PCM lAl7l .nd tho A/Cclutch rolay.
Check tho op.ration of tho A/C:1. Stan the engine.2. Turn the blower switch ON.3. Turn the Ay'C switch ON.
ChGGk for an open in the wi.eIACS linel:Measure voltage betweon ECM/PCM connector terminals A27and 820.
Does the !y'C operate?
Air conditioning 3ignal i3 OK.
Rap.ir opon in the wir6 bdtunaanrh. Ecil/FcM lA27l rnd rh. A/crwitch.
ls voltage less than 1.0 V?
Sub6lftna a known{ood ECM/PCM and rechock. lf symp-tom/indicetion goes away.roplace the original ECM/rcM.See the ah conditionor inspoc-tion {3e€ section 22},
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Page 368 of 1395
ldle Control System
Brake Switch Signal
This signals the ECM/PCM when the brake pedal is depressed.
('97 model)'- - - - -_- Il
PCM CONNECTORSa t32P) D ll6Pl
BKSW(GRN/WHT)
Wire side of female terminals
Insp€ction of Brak. Switch Signal.
Are the brake lights on withoutpressing the brake pedal?
Inspect the HORN, STOP {15 A)fuse in the undeFhood luse/ relaybox.Do the brake lights come on?
Reoair short in the wire be-tween th€ b.ake switch andth6 HoRN, STOP {15 A)luso,Replaco the HoRN, STOP (15
Al fuse.
Repair op6n in the wir€ be-tween the brake switch andtho HORN, STOP (15 Allus6.Inspect the brrke switch (see
aection l9l.
Check tol .n open in the wire{BXSW linel:1. Press the brake pedal.2. Measure voltage between rcMconnector terminais D5 and Agwith the brake pedal pressed.
Reprir open in the wire betweenthe PcM lD5l rnd the brakeswitch.
(To page 11-167)
1 1-166
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