Page 275 of 1681

PGM-FI System
Primary,Heated Oxygen Sensor (HO2S) (Sensor 1) (cont'dl
The scan tool indicates Diagnostic Trouble Code (DTC) P0133: A slow response problem in the Primary
Heated Oxygen Sensor (HO25) (Sensor 1) circuit.
Description
By controlling the airlfuel ratio with a Primary HO2S (Sensor 'l) and a Secondary HO2S (Sensor 2), the deterioration of the
primary HO2S {Sensor 1) can be evaluated by its teedback period. When the feedback period of the HO2S exceeds a cer-
lain value during stable driving conditions, the sensor will be judged as deteriorated.
When deterioration has been detected during two consecutive trips, the MIL comes on and DTC P0133 will be stored
NOTE: ll DTC P013't, P0132 and/or P0'135 are stored at the same time as DTC P0133, troubleshoot those DTCS first, then
troubleshoot DTC P0133.
Possible Cause
. Primary HO2S (sensor 1) Deterioration
o Primary HO2S Heater (sensor 1) Deterioration
. Exhaust system leakage
Troubl€shooting Flowchart
')
litll r
- Tho MIL has boon raDortcd on.- DTC P0133 is storcd.
Problem verificttion:1. Do the ECM Reset Procedure.2. Start the engine. Hold thoengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on.3. Connect the SCS service con-
4. Test'drive Lrnder f o llowingconditions.* 55 mph (89 km/h) steadyspeed- NT in E position, M/T in5th gear- Until readiness code com€son
lnt.flnittcnt ftilu... ay3tam ia OKat thb tiinr. Ch.ck fo. poor con-necliona o. looaa wita! al Cll3
lPrim.ry HO2S lscn.or lll lndECM.
ls DTC P0133 indicated?
Roplacs the Primary HO2S lscn-3or 1),
Page 276 of 1681

Secondary Heated Oxygen Sensor (HO2S) {sensor 2l
The scan tool indicates Diagnostic Trouble Code (DTC) P0137: A low voltage problem in the SecondaryHeated Oxygen Sensor (H02S) (Sensor 2) circuit.
(cont'd)
The MIL ha3 been reDorted on.DTC P0137 is storod.
Problem veritication:1. Do the ECM Reset Procedure.2. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on,3. Check the Secondary H02S(Sensor 2) output voltage at3,000 rpm with the scan 1ool.
Inte.mittent failure, system is OKat lhb time. Ch6ck Ior ooor con-nections or loose wires at C451lSeconddry HO2S {Sensor 2)l andECM.
Does the voltage stay at 0.3 Vor less?
Check for a short in th€ HO2S:1. Turn the ignition switch OFF.2. Discon nect the SecondaryHO2S (Sensor 2) connector.3. Start the engine.4. Check the Secondary H02S(Sensor 2) output whh the scantool.
Does the voltage stay at 0.3 Vor less?
Check tor a short in the wire{SHO2S line):r. I urn rne rgnt on swttch uFF,2. Disconnect the ECM connec,tor D 116P).3. Check for continuity betweenNo. '1 terminal on the Secon-dary HO2S {Sensor 2) connector and body ground.
Ropair short in tho wira bctweenECM (D14) and Secondrry HO2S{Senso.2).
ls there continuity?
Substitute a known-good ECMand recheck. It symptom/indice-taon goes away, replace the origi-nel ECM.
SECONDARYHO2S (Sensor 2l CONNECTOR C451
sHo2sIBLU/REDI f- --
T-l 1 2ltr11(Or ls rl
L
Wire side oI fernale terminals
11-71
Page 278 of 1681
The scan tool indicates Diagnostic Trouble Code (DTC) P0139: A slow response problem in the SeconoarvHeated Oxygen Sensor (H02S) (Sensor 2) circuit.
The MIL has boen reDorted on.DTC P0139 b sto.od.
P.oblem ve tication:1. Do the ECM Reset Procedure.2. Start the engine. Hotd theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on,3. Check the Secondary HO2S{Sensor 2) output ar 3,000 rpmth the scan tool.
Intarmittert lailurg, systsm i! OKat thi! time. Chsck for Door con-nections o. loose wi.es at C451Secondary HO2S lsonsor 2) .ndECM.
Does the voltage stay within0.3 - 0.6 V tortwo minutos?
Page 282 of 1681
Troubleshooting Flowchart
HIGH
- The MIL ha3 been rcoortod on.- OTC P0171 andlor PO'l72.re3tored.
ls the Iuel pressure OK?
ls the fuel pressure too highChock th€ luel p.essure regulator,and tu€l return pipe.Ch€ck the Primary HO2S:1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator lan comes on.2. Check the Primary HO2S{Sensor 1) output with thescan tool.
Chock the tuel pump, fuel feodpipe, fuol fiher, and tuol prcssureregulator.
Does it stay at less than 0.3 Vor more than 0.6 V?Rapl.ce the Primary HO2S {Sen-3or ll.
Check lor a sticking or l€akingEVAP purge control solenoid
With a vacuum pump, apply vacu,um to the EVAP purge controlsolenoid valve.
Does it hold vacuum?
Chock the valvc cl6a.ance3 andadjust it nocessary. lf th. valvocloarance3 are OK, reDlaco thGtuel ini€cto6.
11-77
Page 287 of 1681

I
PGM-FI System
Knock Sensor {KSl (B18C1, 818C5 enginesl
The scan tool indicates Diagnostic Trouble Code (DTC) P0325: A problem in the circuit of the Knock Sensor
{KS).
ECM CONNECIOR D I16P)
Wire side of female terminals
- Tho MIL he3 b6en.eportgd on.- DTC P0325 i3 3tor6d,
Probl6m veriticalion:1. Do the ECM Reset Proc€dure.2. Start the engine. Hold theengine at 3,000 rpm with noload {in Park or neutral} untilthe radiator lan comes on,then let it idle.3. Hold the engine at 3,000 -
4,000 rpm for 10 seconds.
Intarmitt.nl failurc, ay3tem i3 OKrt thii timc llest driva mav b.naccrsrryl.Chcck for poor connactions o.loos. wir.. botw..n Cl33 knocks.nlor (KSl rnd EcM.
Ch6ck {or a 3hort in tho wirc IKSlin6l:1. Turn the ignition switch OFF.2. Disconnect the knock sensorconnector,3. Check for continuity betweenECM connector terminals D6and body ground.
R.o.i. short in thG wire batwaanECM lD6l rnd knock..n3or.
Check for an opcn in lho wiro
IKS lin.l:Check for continuity between ECMconnector terminal D6 and knocksensor connector terminal No. 1.
Reprir op.n in tho wira bttw..nECM lD6l and knock ..Nor.
Substitute a known-good knocksensor and recheck.
Raplac6 thc odginrl knock sanror.ls DTC P0325 is indicated?
Substitut6 . known-good ECM.nd rocheck. lf aymptom/indic.-tion 9003 away, .opbcc thc origi-nal ECM.Wire side of female terminals
Page 303 of 1681

ldle Control System
ldle Control System
i P0505 | fne scan tool indicates Diagnostic Trouble Code (DTC) P0505: ldle control system malfunction,
NOTE: ll DTC Pl508 is stored at the same time as DTC P0505, troubleshoor DTC P1508 first. then troubleshoot DTC P0505.
Possible Cause
. IAC valve mechanical malfunctiorr
. Fast idle thermo valve malfunction (A"/T)
. Throttle body clogged port, improper adjustment
. Intake manifold, gasket leakage
. Intake air hose loose, leakage
a Vacuum hoses leakage
. ECT sensor incorrect output
. Throttle Position sensor incorrect output
Troubleshooting Flowchart
Problem verification:1. Start the engine. Hold theengine at 3,000 rpm wath noload 1in Park or neutral) untilthe radiator fan comes on,then let it idle.2. With the scan tool, check thefollowing items.- Throttle position should beapprox. 10% with the throttle fully closed.Engine coolant tempera-ture should be 116 212F(80 - 100'c).lf they are not within thespec., repair the faulty sensor crrcuft,3 Check the engine speed atidle with no-load conditions:headlights, blower fan, reardefogger, radiator fan, and airconditioner are not operating,
- The MIL has been reported on.- DTC P0505 is stored.
ls it 750 t 50 rpm (81881,
818C1 engines), 800 I 50 rpm(818C5 engine)?
Intermittent failur6, svstsm is OKat this tim€.
ls it 550 rpm (81881,818C1
engines), 600 rpm {818C5enginelor less?
-98
(To page 11'99)(To page 11-99)
Page 306 of 1681

This signals the ECM when the Alternator (ALT) is charging.
Alternator (ALT) FR Signal
Check lor a short in th€ wire {ALTF line):1. Oisconnect the ALT GRN 4P(3P)* connector from the ALT.2. Turn the ignition switch ON {ll).3. Measure voltage between ECMconnector terminals C17 and A9.
ECM CONNECTORSA t32Pt
LG1
c 13lPl
ALT F(WHT/FEDI
Wire side of female terminals
ALT GRN 4P CONN€CTOR {C119}
JUMPER WIRE
Wire side of female terminals
ALT GRN 3P CONNECTOB {C119)*
JUMP€RWIRE
Wire side ot female terminals
12 15 t6 rr t8 19I
?
oALT F(WHT/REOI
23aI10
t112t3t5l6r819 ,/21
./,/,/2a29
[,ALT FIWHT/RED)
12339
11 12l517 tla19 ,/21
Inspection of ALT FR Signal.
Check for a shon in the wire {ALTF line):1. Turn the ignition switch OFF.2. Disconnecl the negative baatery cable from the battery.3. Disconnect the ECM connectorc (31P).
4. Check for continuity betweenbody ground and ECM con-nector terminal C17.
ls there approx.5 V?
Check the operation ofthe ALT:1. Turn the;Onition switch OFF-2. Reconnect the ALT GRN 4P(3P)* connector to the ALT.3. Start the engine. Hold theengine at 3,000 rpm wkh noload {in Park or neutral) untilthe radiator fan comes on,then let it idle.4. Measure voltage bet/veen ECMcon nector termina ls C17 and A9.
Ropair short in the wir6 betweenth6 ECM (C17) and the ALT.
Substitute a known-good ECMand recheck. It prescribed voltagGis now available, replace th€ origi-nal ECM.
Does the voltage decrease whenheadlights and rear defogger areturned on?ALT FR signal is OK.
Check tor an open in the wire {ALTF line):1. Turn the ignition switch OFF-2. Disconnect the negative bat-tery cable from the battery.3. Disconnect the ECM connector C (31P).
4. Disconnect the ALT GRN 4P(3Pi* connector from the ALT.5. Connect the ALT GRN 4P (3p)*
connector terminal No. 4 (No.'l)* to body ground with a
6. Check for continuity betweenbody ground and ECM connector terminal C17.
Ropair open wire bstw€an theECM {C17} and rhe ALT.ls there continuity?
ri Canada
11-101
Page 315 of 1681

ldle Control System
Fast ldle Thermo Valve (A/T model onlylFast ldle I nermo valve (A/ | mooel
Description
To prevent erratic running when the engine is warming
up. it is necessary to raise the idle speed. The fast idle
thermo valve is controlled by a thermowax plunger.
When the engine is cold, the engine coolant surround-
ing the thermowax contracts the plunger, allowing addi
tional air to be bvoassed into the intake manifold so that
the engine idles taster. When the engine reaches operat-
ing temperature, the valve closes. reducing the amount
of air bypassing into the manifold.
FAST IDLE THERMO
VALVE
VALVE
wAx
Inspection
NOTE: The fast idle thermo valve is factory adiusted; it
should not be disassembled.
1. Remove the intake air duct from the throttle body.
2. Start the engine.
3. Put your finger over the lower port in throttle body
and make sure that there is air flow with the engine
cold {engine coolant temperature below 86'F, 30"c).
LOWERPORT
lf there is no air flow, replace the last idle thermo
valve and retest.
Start the engine. Hold the engine at 3,000 rpm with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
Check that valve is completely closed. lf not, air suc-
tion can be felt at the lower port in the throttle body.
l{ any suction is felt, the valve is leaking. Check
engine coolant level and for air in the engine
coolant system (see section 10). It OK, replace the
fast idle thermo valve and recheck.
5.
{1.0 kg.m,7.2lbftl
l
11-110
lL.