Page 319 of 1395

Secondary Heated Oxygen Sensor (Secondary HO2S) (Sensor 2)
The scan tool indicates Diagnostic Trouble code (DTC) P0137: A low voltage problem in the secondary Heated
Oxygen Sensor (Secondary HO2S) (Sensor 2) circuit.
SECONDARY HO2S ls.nlor 2)4P CONNECTOB lC721l
Wire side of lemale terminals
(cont'd)
11-117
The MIL hrs been reported on.DTC P0137 is stored.
Problem veritication:1. Do the ECM/PCM Reset Pro'cedure.2. Start the engine. Hold theengine at 3,000 rpm wilh no
load (in Park or neutral) untalthe radiator {an comes on,3. Check the Secondary H02S
lSensor 2) output voltage at3,000 rpm with the scan tool.
lnlermittent failure, 3ystem i5 OK
at this time. Check tor Poor con'
noction3 or loose wires at C127
{locatod on ECM/PCM bracket},C721 (Secondary HO2S, Sensor2l and at the ECM/PCM.
Does the voltage stay at 0.3 V
or less?
Check for a short in the SecondaryHO2S:1. Turn the ignition switch OFF.2. Disconnect the SecondaryHO2S lSensor 2) 4P connector.3. Start the engine.4. Check the Secondary HO25(Sensor 2) output with the scantool.
Check lor a short in the wire(SHO2S linel:1. Turn the ignition switch OFF.2. Disco n nect the ECM/PCMconnector {D (16P}, A (32P}').
3. Check for continuity betweenthe Secondary HO2S (Sensor
2i 4P connector terminal No. 1and body ground.
Reoair short in the wire b€twoen
rhe ECM/PCM |D14, 423*l and
the Secondary HO2S {Sensor 2).
Substitute a known-good ECM/PCM and rocheck. lf symptom/indication goes away, replacethe original ECM/PCM.
*: '98 - 00 modeis
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Page 320 of 1395

PGM-FI System
Secondary Heated Oxygen Sensor (Secondary HO2SI (Sensor 2l (cont'dl
The scan tool indicates Diagnostic Trouble Code (DTC) P0138: A high voltage problem in the Secondary Heated
Oxygen Sensor (Secondary HO2S) (Sensor 2) circuit.
SECONDABY HO2S (Sonror 2)1P CONNECTOR rC721 l
sHo2s{WHT/REDI
sH()2sGIGFN/WHTI
Wire side of female terminals
PCM COI{NECTOR D {16PI
sHo2sG(RED/YELI
JUMPER WIRE
Wirc side ol lemale terminals
{To page 11-119)
1 1-1 18
The MIL hra b€on Eported on,OTC m138 b stor.d.
PJoblcm v6dtic.tion:1. Do the ECM/PCM Resot Pro-cedure,Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) trntilthe radiator lan comes on.Check the Secondary HO2S(Sensor 2) outpl.rt voltage at3,000 rpm with the scan tool.
Int.rmitto tailurc, syst.m b OKrt ihi! timo. Chack fo. poo. oon-noctioni or looaa wiiaa at C127lloc.ted on EcM/PcM br.cket),C721 (Second!ry llO2S, Sonlol2).nd at th. ECM/PCM.
Does the voltage stay at 0.6 Vor more?
Chock for an opon in the SocondaryHO2S:1. Turn the ignition switch OFF.2. Disconnect the SecondaryHO2S (Sensor 2) 4P connector.3. Connect the Socondary HO2S(Sensor 2) 4P connector ter-minals No. 1 and No. 2 with a
4. Turn the ignition switch ON {ll}.5. Check the Secondary HO2S{Sensor 2) output voltage withthe scan tool.
ls there 0.6 V or more?
Ch6ck for an open in thg wiro3(SH()2S, SG2 line3l:1. Turn the ignition switch OFF.2. Connect rcM connector termi-nals 014 and D13 with a
J!mper wite.3. Turn the ignition switch ON (ll).
4. Check the S€condary HO2S(S€nsor 2) output voltagewith the scan tool.
Rapair op6n in tho wir. b€{woantho PcM lDla or Dl3l .nd thoS.condlry HO2S {Senlor 21.
lsthere 0.6 V or more?
('97 model)
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Page 322 of 1395
PGM-FI System
Secondary Heated Oxygen Sensor (secondary HO2SI (sensor 2l (cont,d)
lTol3al The scan tool indicates Diagnostic Trouble Code (DTC) P0139: A slow response probtem in the Secondary Heated- Uxygen Sensor (HO2S) (Sensor 2l circuit.
- The MIL has b€en reoorted on.- DTC P0139 is storad.
Probl€m ve.itication:1. Do the ECM/PCM Reset Procedure,Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on.Check the Secondary HO2S(Sonsor 2) output at 3,000 rpmwith the scan tool.
lntehittont failure, 3ystem is OKat this time. Chock for poor con-nections o. loose wi.es at C127(located on ECM/PCM brack€t),C721 {Secondary HO2S, Sensor 2land at the EcM/PcM.
Does the voltage stay within0.3 - 0.6 V for two minutes?
11-120
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Page 327 of 1395
Troubleshooting Flowchart
- The MIL has been rePorted on- DTC P0171 andlot P0172 are
stored,
Check the lu6l pressuro regulator
and tusl relum PiPe.ls the lLrel pressure too high
Check lhe Primaty HO2S:1. Start the engine. Hold the
engine at 3,000 rpm with no
load (in Park ot neutral) until
the radiator fan comes on
2. Check the Primary HO2S(Sensor 1) outPut with the
scan tool.
Check lh€ fuel pumP. fuel faedpipe. fuel fiher, and luel Prossurc.eguhior.
Does it stay at lessthan 0.3 V
or more than 0.6 V?
Check for a sticking or leaking
EVAP purge control solenoid
With a vacuum pump, aPPIY vacu
um to the EVAP Purge control
solenoid valve from the intake
manifold side.
Does it hold vacuum?
Check th6 valve clearanc€s and
adjust il necessary. It the valv€
clearances are OK, replace the
fuel iniectors.
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Page 332 of 1395

PGM-FI System
Knock Sensor {KSl
('99 - 00 models) The scan tool indicates Diagnostic Troublo Code (DTC) P0325: A malfunction in the circuit ofthe Knock Sensor (KS).
ECM/PCM CONNECTOR C 131P}
Wire side of female terminals
KS 1P CONNECTOR IC13?'
KSIRED/BLU)
KS(BED/BLU)
Wire side ol femaletermtnals
ECM/PCM CONNECTORc (31P)
- The MIL has been rooorted on.- DTC m325 is storod.
Problem verification:1. Do the ECM/PCir, Reset Procedure,2. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator tan comes on,then let it idle.3. Hold the engine at 3,000 -
4,000 rpm for at least 60 sec-onds,
Intermittent lailu.e, 3ystom is OKat thi3 tim. (te3t drive m.y benacalLrYr.Chock to. poor connsctions olloora wiros rt C137 lknock aon-.o. (KS)) and ar the ECM/FCM.
Ch€ck tor a short in the wir6 {KSlinel:1. Turn the ignition switch OFF.2, Disconnect the knock sensorlP connector.3. Check lor continuity betweenECM/PCM connector terminals C3 and body ground.
Replil rhort in the n irg b6{wocntho ECM/PCM lc:ll and the knocks€ngr1.
Check fo..n open in the wire{KS line):Check for continuity betweenECM/PCM connector terminal C3and knock sensor connector ter,minal No. 1.
B.pair opon in the wirc lrotweenlho ECM/PCM lctl and thc knockacnsor.
ls there cont;nuity?
Substitute a known-good knocksensor and recheck.
ls DTC P0325 indicated?Bcpl.ce the original knock 3€nsor,
Substituto a known-good ECM/PCM and .echeck. lf 3ymptom/indication goes away, replacethe original ECM/PCM.
NOTE: Torque the knock s6nsor to31 N.m (3.2 kgl.m, 23 lbf.ft).
1 1-130
Wire side ot female terminals
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Page 339 of 1395

Barometric Pressure (BARO) Sensor
The scan tool indicates Diagnostic Trouble Code (DTC) P1106: A range/performsnce problem in the Barometric
Pressure {BARO) Sensor circuit.
The MIL has been reDorted on.OTC Pl106 b slored.
Problem ve.ification:1. Oo the ECM/PCM reset pro'
ceoure.2. Start the engine. Hold theengine at 3,000 rpm with noload (;n Park or neutral) untilthe radiator lan comes on, thenlet it idle.3. Connect the SCS service con-nector,4. Test'drive with the A/T in Eposition, M/T in 4th gear.
5. Accelerate Ior five secondsusing wide open throttle.
Intermittent fsilure, sy3tom i5 OKat this time.ls DTC P1106 indicated?
Substitute a known-good ECM/PCM .nd recheck. It symptom/indication goes away, replace theorigioal ECM/PCM.
fTiloz l
tP11o8l
The scan tool indicates Diagnostic Trouble Code (DTC) P1107: A low
The scan tool indicates Diagnostic Trouble Code (DTC) Pl108: A
circuit.
voltage problem in the Baro sensor circuit.
high voltage problem in the Baro sensor
- The MIL h.3 b€en roport€d on.- OTC Pl10? or Pl108 i3 stored.
Problom veritic.lion:L Do the ECM/PCM Reset Pro-cedure.2. Turn the ignition switch ON (lli.
Intarmittoni failure, lystom b OKat thb time.ls DTC P1107 or P1108 indicated?
Sub3tituto a known-good ECM/PCM and rcch6ck. ll symptom/indication 9oo3 away. .oplacorho o.igin.l ECM/PCM.
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Page 352 of 1395

ldle Control System
ldle Control System
I P0505 | The scan tool indicates Diagnostic T.ouble Code (DTCI PO5O5: ldlecontrol svstem mattunction.
NOTE: lf DTC P1508 is stored at the same time as DTC P0505, troubleshoot DTC P1508 first. then troubleshoot DTC p0505.
Possibls Cause
. IAC valve mechanical malfunction. Throttle body clogged port, improper adlustment. Intake manifold gasket leakaging. Intake air hose loose leakaging. Vacuum hose leakaging
a ECT sensor incorrect output. Throttle Position sensor incorrect output
Troubleshooting Flowchart
The MIL has been reDorted on.DTC P0505 is sto.ed.
Problem verificationi1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator Ian comes on, thenlet it idle.2. With the scan tool, check thelollowing items.- Throttle position should beapprox. 10% with the throt-tle {ully closed.- Engine coolant temperature shorJld be 194 - 205'F(90 - 96"C).lf they are not within thespec., repair the faulty sen-sor circuit.3 Check the engine speed atidle with no-load conditions:headlights, blower fan. reardefogger, radiator lan, and airconditioner are not operaling,
Inte.mittent failure. syltem is OKat this time.ls it 750 {730)* i 50 rpm?
ls il 700 (680)' rpm or less?
{To page 11-151)(To page 1'l-151)
l:'99 - 00 models
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Page 361 of 1395

Alternator (ALT) FR Signal
This signals the ECM/PCM when the Alternator (ALTI is charging.
,97 modet: PCM GONNECTORS
wire side of female terminals
ALT CONNECTOR (C1O5I
lPr-F- ALT F
lll2llw|{frREDl|3.r-'l-
lruueen wne
c (31P|
wire side ol f€male terminals
PCM CONNECTOR C I31P)
3Pr
JUMPERWIRE
Inspection ot ALT FR Signal.
Check lor a short in the wire
{ALT F line}:1. Disconnect the 4P 13Pi* connector from the ALT.2. Turn the ignition switch ON (ll)
3, Measure voltage betweenPCM connector terminals C17
and A9.Check for a short in the wire(ALT F linel:1. Turn the ignition switch OFF.2. Disconnect the negative bat'tery cable from the battery.3. Disconnect PCM connector C(31P).
4. Check for continuity betweenbody ground and PCM connector terminal C17.
ls there approx. 5 V?
Check th€ ope.ation of the ALT:
1. Turn the ignition switch OFF2. Reconnect the ALT 4P {3Pi*connector to the ALT.3. Start the engine. Hold theengine at 3,000 rpm with no
load (in Park or neutral) untilthe radiator fan comes on,
then let it idle.4. Measure voltage betweenPCM connector terminals C17and A9.
Ropeir short in the wir6 betweonthe PCM lC17l and the ALT.
Substitut. a known-good PCM
and recheck. lf prescribed volt-
age is now availablo, replace the
originalPCM.
Does the voltage decrease when
headlights and rear defogger are
turned on?ALT FR signal b OK.
Ch€d( for an op€n in tho wire IALTF linel:1. Turn the ignition switch OFF.2. Disconnect the negative bat-tery cable lrom the battery.3. Disconnect PCM connector C(31P).
4. Disconnect the 4P (3P)* con-nector lrom the ALT.5. Connect the ALT 4P (3P)* con-nector terminal No. 4 (No. 1)*to body ground with a iumper
6. Check for continuity betweenbody ground and PCN4 con'nector terminal Cl7.
Repair open wi.e between thePCM lCl7l and the ALT.ls there continuity?
ALT F IWHT/REDI
Wire side of female terminals
1 1-159
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