Page 402 of 1395
Emission Control System
Three Way Catalytic Converter {TWCI (cont'd}
1P0420 Thescantool indicates Diagnostic Trouble Code (DTC) P0420: Catalyst system efficiency belowthreshold.
DescriDtion
This system evaluates the catalyst's capacity by means of the HO2S (Primary and Secondary) output during stable driving
conditions. lf deterioration has been detected during three consecutive driving cycles, the MIL comes on and DTC P0420 will
be stored.
NOTE: lf some of the DTCS listed below are stored at the same time as DTC P0420, troubleshoot those DTCS first. then
troubleshoot DTC P0420.
P0137, P0138: Secondary HO2S (Sensor 2)
P0141: Secondary HO2S (Sensor 2) Heater
Possible Cause
. IWC Deterioration
. Exhaust system leakage
Troubleshooting Flowchart
- The MIL has been reDoried on.- DTC P0420 is stored.
Problem verification:1. Do the ECM/PCM Reset Procedure,2. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutrali untilthe radiator fan comes on.3. Connect the SCS service connector.4. Test-drive 40 - 55 mph (64 - 88km/h) for approx. lwo minutes.Then decelerate for at least 3seconds with the throftle completely closed. Then reducethe vehicle speed to 35 mph
156 km/h), and try to hold ituntil the readiness code
Intermittent tailure. system is OKat this time.ls DTC P0420 indicated?
Check the TWC (see section 9).lI nocessary, replace the TwC.
11-200
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Page 407 of 1395
'97 model:
The scan tool indicates Diagnostic Trouble Code (DTC) P0441: Evaporative Emission (EVAP) control system
insufficient purge flow.
Description
By monitoring the purge line vacuum with the MAP sensor, the PCM can detect insufficient EVAP control system purge
flow.
Possiblo Cause
. EVAP Purge Control Solenoid Valve
. EVAP Purge Control Solenoid Valve Circuit
. EVAP Control Canister
. Vacuum Lines
. PCM
Troubleshooting Flowchart
EVAP PURGE CONTROL
SO1TNOID VALVE 2P
CoNNECTOR (C108)
(v)
YL
Wire side of female
termrnals
(cont'd)
11-205
Th€ MIL has b€en reooited on.DTC P0441 is .tored.
Problem verificationl1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neut.al) untilthe radiator fan comes on.2. Do the PCM Reset Procedure.3. Connect the SCS service con-nector,4. Test drive under following con'ditions on the road.- without any electrical load- Transmission in @ or @position- Engine speed between1 ,2OO - 2,4OO rpfi.- Decelerate from 50 mph (80
km/h)to 15 mph (24 km/h)Intermittent trilure, sydern is OKat this time. Check for Door con-nections or loose wir€3 at C108
IEVAP purge control solonoidvalvol .nd at the PCM.
ls DTC P0441 indicated?
Check tor an open in the wire (lcl
linel:1. Turn the ignition switch OFF.2. Disconnect the EVAP purge
control solenoid valve 2P con-nector.3. Turn the ignition switch ON (ll).
4. Measure voltage between bodyground and the EVAP purge
control solenoid valve 2P con-nector terminal No. '1,
R€pafu open in thc wir6 b€tw€enthG EVAP purge control solenoidvalve and the No. 15 ALTEBNA-TOR SP SENSOR (7.5 A)fuse.
ls there batlery voltage?
(To page 11'206)
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Page 408 of 1395
Emission Control System
Evaporative Emission (EVAP) Controls (cont'dl
(From page 11-205)PCM CONNECTOR A (32PI
JUMPER wlRE
PCS IRED/YELI
Wire side of female terminais
PG1 (BLKI
Chsck th6 EVAP purgo controlsolonoid valve:'L Reconnect the EVAP purgecontrol solenoid valve 2P con-nector.2. Connect PCM connector terminals 415 and A10 with a
Chscl to. an op6n or 3hort in th€wiro (PCS lin6):Measure voltage between PCMconnector terminal A15 and bodygrouno,
Does the solenoid valve clickwhen the jumper is connected?
Chock for . .hort in tho wiJe IPCSline):1. Turn the ignition switch OFF.2. Disconnect the PCM connec-tor A (32P).
3. Disconnect the EVAP purge
control solenoid valve 2P con-nector,4. Check for continuity betweenbody ground and PCM con-nector terminal A15.
ls there battery voltage?
Rooair short in tho wir6 bctweenthe EVAP purge control 3olenoidvalvo and tho PCM (A151.
Ropair open in the wir6 betwoonthe EVAP pu]go control .olonoidv.lve end the PCM (A15).
Check the vacuum lin6:Check the vacuum lines of EVAPsystem tor misrouting, leakage,brsakago and clogging.
Are the vacuum lines OK?
(To pago 11'207)
11-206
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Page 409 of 1395
Chack iho EVAP purge controlsolenoid valve:1. Disconnect the vacuum hosetrom the EVAP controlcanister.2, Connect the vacuum pump tothe hose and apply vacuum,
Does it hold vacuum?
Chgck thg EVAP control csnbter:1. Reconnect the vacuum hose tothe EVAP control canister.2. Connect a vac!um gauge tothe purge air hose.3. Connect PCM connector terminals A15 and 410 with ajumper wire.4. Stan the engine.5. Check the vacuum.
Check the EVAP two way valve(see page 11'224).
Does the EVAP two way valvework properly?Rapbce the EVAP two wey valve.
Substitute a known-good PCMand rechock. It symptom/indica-tion gocs away, roplacg tho origi-nrl rcM.
(From page 11-206)
JUMPEF WIRE
<\
EVAP CONTNOLCANISTER
VACUUMPUMPIGAUGE,0-30 in.Hg4973X -
0il1 -
xxxxx
VACUUM/PRESSUREGAUGE0-4 in.Hg07JA2 - ml(x)o8
wire side of female terminals
{cont'd)
-20711
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Page 410 of 1395
Emission Control System
Evaporative Emission (EVAP) Controls (cont'd)
99 - 00 models:
The scan tool indicates Diagnostic Trouble Code {DTC) P0451: The Fuel Tank Pressure sensor circuit range/oerformance Droblem.
ECM/PCM CONNECTORS
SG2 {GRN/BLK)
Wire side of {emaleterminals
FUEL TANKPRESSURESENSOR
VACUUMPUMP/GAUGE.0 -30 in.H9A973X - 041 -
XXXXX
- The MIL har been rooort€d on.- DTC P0451 b storod.
Check lor th6 tu6l tank pr€ssurelen30r:1. Do the ECM/PCM Reset Proce,oure.2. Remove the fuelfill cap.3. Turn the ignition switch ON (ll).4. Monitor the FTP Sensor voltage with the Honda PGMTester, or measure voltagebetween ECM/PCM connectorterminals A29 and C18.
Chock tho vacuum lin6s torrGlriction o. blockago repair asnecessary. lf OK, roplace the fueltank Drer3ur€ sentor.
ls there approx. 2.5 V?
Check for the fuel tank piessureSensot:L Disconnect the hose betweenthe EVAP two way valve andthe fuel tank pressure sensor atthe EVAP two way valve end.2. Connect a vacuum pump tothe open end ofthat hose.3. Turn the ignition switch ON (lll.4. Monitor the FTP S€nsor volt-age with the Honda PGMTester, or measure voltagebetween ECNI/PCNI connectorterminals A29 and C18, andcarefully appiy vacuum on thehose one stroke at a time.5. The voltage should smoothlydrop from the staning approx.2.5 V down to approx. 1.5 V.STOP applying vacuum whenthe voltage drops to approx.1.5 V or damage to the tueltank pressure sensor may
Does the voltage drop to approx.1.5 V and hold?
Intermittent tailuro. sv3tem is OKat this tim€. Chack to. poor con-n€ction6 or 10036 hose at fu6ltank pres3ure ionsor and fueltrnk.
a t32Pl
PTANK ILT GRNI
WAY VALVE
11-208
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Page 411 of 1395
'98 - 00 mod€ls:
The scan tool indicates Diagnostic Trouble Code (DTC) P0452: A low voltage problem in the Fuel Tank Pressure
sensof.
The fuel tank Dressure sensor converts fuel tank absolute pressure into electrical signals and inputs the ECM/PCM.
OUTPUTVOLTAGEtvl{.5
0,5-? KPA(-50 mmHg,-2 in.Hgl
+7 kPr
l5O mmHg,2 in.Hgl
PRESSURE
ECM/PCM CONNECTOR A (32P)
Wire side ot female terminals
FUEL TANKPRESSURE SENSOR3P CONNECTOR tc6a6l
voc2(YEL/BLUI
Wire side ol fsmale terminals
(cont'd)
11-209
Th. MIL has been reoorted on.DTC m452 is stored.
Check the vacuum lin6:Check the vacuum lines of the fueltank pressure sensor for misrouting, leakage, breakage and clog-ging.
Are the vacuum lines OK?
Problem veriticstion:1. Do the ECM/PCM ResetProcedure-2. Remove the luelfillcap.3. Turn the ignition switch ONfl r).4. Monitor the FTP Sensor volt'age with the Honda PGMTester, or measure voltagebetween body ground andECM/PCM terminalA29.Intermittent failuro, system is OKat this lima. Chack lor Door con-nections or loose wi.es at C580llocrted rt access panell, C646lluel tank Daessure sensor) andat the ECM/PCM.
ls lhere approx. 2.5 V?
Check lor an open in wir€ lVeC2line):1. Turn the ignition switch OFF.2. Reinstallthe fuel fill cap.3. Disconnect the fuel tank pres-
sure sensor 3P connector,4. Turn the ignition switch ON (ll).
5- Measure voltage between thefLrel tank pressure sensor 3Pconnector No. 1 terminal andNo.2 terminal.
Replir opon in the wire b€tw€enth6 tuel tank pressure lensot andthe ECM/PCM {A29).ls there approx. 5 V?
YES
(To page 11-210)
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Page 412 of 1395
Emission Control System
Evaporative Emission (EVAP) Controls (cont'dl
FUEL TANKPRESSUNE SENSOR3P CONNECTOR tc646l
Wire side of female terminals
(From page l1'209)
Check lor a short in the wireIPTANK Iine}:Measure voltage betlveen the fueltank pressure sensor 3P connectorNo. 3terminal and No. 2terminal.
ls there approx.5 V?
Check for a short in the wire(PTANK line):1. Turn the ignition switch OFF.2. Disco n nect the ECM/PCMconnector A {32P).3. Check for continuity betweenthe fuel tank pressure sensor3P connector No. 3 terminalsand body ground.
Repair short in the wira betwgonthe fuel trnk prossure s6nsor andtho ECM/PCM lA29).
Sub.tituto a known-good ECM/PCM and r€check. lf 3ymptom/indication goer !way. replaceth6 original ECM/PCM.
11-210
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Page 413 of 1395
'98 - 00 modals:
The scan tool indicates Diagnostic Trouble Code (DTC) P0453: A high voltage problem in the Fuel Tank Pressure
sensor.
ECM/PCM CONNECTOR A {32PI
Wire sido ot fema16 t€rminals
FUEL TANXPf,ESSUBE SENSOR3p CONNECTOR {C6,a6l
vcc2IYEL/BLUI
sG2IGRN/BLKI
sG2(GRN/BLK}
Wire side ot female terminals
PTANKILT GRNI
(cont'd)
11-211
PTANK ILT GRN)
123
Thc MIL has b6on ropottcd on.DTC mia53 is dorcd.
Ch6ck tho vacuum linos:Check the vacuum lines of the
fuel tank pressure sensor lor mis-
routing, leakage, breakage and
cloggrng.
Are the vacuum lines OK?
Problorn verif ication:1. Do the ECM/PCM ResetProcedute.2. Remove the fuel fill cap.
3. Turn the ignition switch ON
{[).4. Monitor the FTP Sensor volt-age with the Honda PGM
Tester, or measure voltagebetween body ground and
ECM,PCM terminal429.Intarmittent tailuro, sv3iom b OKat this timo. Chock for poor con-nection3 or loo$ wire3 at C580(locstod .t .cc$r p.nell, C6a6(fucl tank pros3ure son3orl and.t the ECM/FCM.
ls there approx. 2.5 V?
Check lor an open in tho wiro
lSG2lin6l:1. Turn the ignition switch OFF.
2. R6installthe Iuel fill cap.3. Disconnect the Iu6l tank pres_
sure sensor 3P connector,4. Turn the ignition switch ON (ll).
5. M€asure voltago between thetuel tank pressure sensor 3P
connector terminals No. '! andNo.2.
Replir op€n in th. wi.c b€{weentha fuel tank Dio'sute sansot andtho EC|,/PCM {Cl8}.ls there approx. 5 V?
Ch€ck for an opon in tho wiro(PTANK linel:Measure voltage between thefuel tank pressure sensor 3P con-nector No. 3 terminal and No. 2terminal.
ls there approx. 5 V?
\To page 11-212)
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