1999 HONDA CR-V Workshop Manual

Emission Control System
System Description
The emission control system includes, a Three Way
Catalytic Converter {TWC), Positive Crankcase Ventilation
(PCV) svstem and Evaporative Emission (€VAP) Control
system. The emission control system is designed to meet
federal and state emission standards.
Tailpipe Emission
Inspsction
!@ Do not smoke during this procsdura. Keep
any open tlame away from your work area.
1. 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,
Connect a tachometer.
Check and, if necessary, adjust the idle speed, (see
page 11-169, 170).
Warm up and calibrate the CO meter according to the
meter manufacturer's instructions.
Check idle CO with the headlights, heater blower, rear
window defogger, cooling fan, and air conditioner off.
(Canada) Pull the parking brake lever up. Start the
engine, then check that the headlights are off.
CO meter should indicate 0.1% maximum.
4.
Three Way Catalytic Converter (TWCI
DsscriDtion
Three Way Catalytic Convertsr lTwcl:
The Three wav Catalvtic Converter (TWC) is used to
convert hydrocarbons (HC), carbon monoxide (CO), and
oxides of nitrogen (NOx) in the exhaust gas to carbon
dioxide (COr), dinitrogen (Nr) and water vapor,
{cont'd)
1 1-199
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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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Positive Grankcase Ventilation (PGVI System
Description
The Positive Crankcase Ventilation (PCV) svstem is
designed to prevent blow-by gas from escaping to the
atmosphere. The PCV valve contains a spring-loaded
plunger, When the engine starts, the plunger in the PCV
valve is lifted in proportion to intake manitold vacuum and
the blow-by gas is drawn directly into the intake manifold.
-: BLOW.BY VAPOR-: FRESH AIR
i/lAlrllFOLD
Inspoction
1. Check the PCV hoses and connections for leaks and
clogging.
'97 - 98 models:
'99 - (X) models:
BREATHERHOSE
(cont'd)
11-201
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Emission Control System
Positive Crankcase Ventilation (PCV) System (cont'dl
2. At idle, make sure there is a clicking sound from the
PCV valve when the hose between the PCV valve
and intake manifold is lightly pinched with your fin-
gers or pliers.
'97 - 98 models:
'99 - 00 modelsi
lf there is no clicking sound, check the PCV valvegrocrmet for cracks or damage, lf the grommet is
OK, reDlace the PCV valve and recheck.
Gently pinch here.
Gently pinch here.
11-202
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EVAP PURGE CONTROL SOLENOID VALVE DUTY CONTROLLED AFTER
STARTING ENGINE
ENGINE COOLANT TEMPERATURE ABOVE 154"F (68'C)
Evaporative Emission (EVAP) Controls
Description:
The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The
system consists of the following components:
A. Evaporative Emission (EVAPI Control Canister
An EVAP control canister is used for the temporary storage of fuel vapor until the luel vapor can be purged from the
EVAP control canister into the enqine and burned.
B. Vapor Purge ConirolSystem
EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a pon
on the intake manifold. The purging vacuum is controlled by the EVAP purge control solenoid valve.
C. Fuel Tank Vapor Control System
When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and
regulates the flow ot fuel vapor to the EVAP control canister.
'97 model:
EVAPPURGECONTROL
VALVEFromNo. 15BLK/ /ALTERNATORYEL I sP SENSOR r7.s At(in the under-dashfuse/relay box)
VARIOUSSENSORFEESH AIF
BLK
I
FUEI- TANK
(cont'd)
11-203
INTAKE MANIFOLD
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Emission Gontrol System
Evaporative Emission (EVAP) Controls (cont'dl
'98 - 0O models:
EVAPTHREE WAYVALVE
EVAPCONTROLCANISTERVENT SHUTVALVE
'EL/BLU ._^_-:.*,".. <3|ltAIS"o[..^,
1in the under-dashtuse/relay box)
FrofiBLK/WHT < NO. 15
GRN/BLK
BLU
EVAPBYPASSSOLENOID
EVAP PURGECONTROLSoLENOtOVALVE
L LT GRN/WHT ,
RED/YEL
MANIFOLD
VARIOUSSENSOR
EVAPTWO WAYVALVEVALVE
FUEL TANK
SLK
11-204
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'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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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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