P0420 HONDA CR-V 1999 RD1-RD3 / 1.G Workshop Manual

Troubleshooting
Diagnostic Trouble Code (DTCI Chart (cont'd)
*: These DTCS will be indicated by the blinking o{ the Malfunction Indicator Lamp (MlL) with the SCS service connector
connected.**: The E (El*s indicator light and the Malfunction Indicator Lamp {MlL) may come on simultaneously,*1; A/T *3: '97 model *5: '99 - 00 models*2: MlT *4: '98 model
11-76
DTClMlL indicationlDetection hemProbable Caus.Page
P0137(63)Secondary Heated Oxygen SensorCircuit Low Voltage{Sensor 2)
Shon in Secondary HO2S (Sensor 2) circuatSecondary HO2S (Sensor 2)ECM/PCM
'n-1t7
P0138 (63)Secondary Heated Oxygen SensorCircuit High VoltageOpen in Secondary HO2S (Sensor 2) circuitSecondary HO2S (Sensor 2)EC|\il/PCM11118
P0139{63)Secondary Heated Oxygen Sensor
lSensor 2i
Secondary HO2S (Sensor 2)11-120
P0141 (65)Second6ry Heated Oxygen Sensor HeaterCircuit Malfunction(Sensor 2)
Open orshon in Secondary HO2S (Sensor 2)heater circuitEC|V/PCtu11't2l
P0r71 (45)
System Too LeanFuel supply systemPrimary HOzS (Sensor 1)
Contaminated fuel
Exhaust leakage
11124
P0112 (45)
System Too RichFuel supplv systemPrimary HO2S (Sensor 1)
Contaminated fuel11 124
and
Po3ol ltr \P0302 112 |P0303 173 iP0304 \74 t
Random Mistirelgnition systemFuel supply system
IAC valveContaminated fuelLack of fuel
11-126
P0301 /71 \P0302 112 |P0303 173 |P0304 \7 4l
- Cylinder 1- Cylinder 2Cylinder 3- Cylinder 4Misfire Detected
Fuel injectorFuel injector circuitlgnition system't't 127
P0325*5{23)Knock Sensor {KS) Circuit MalfunctionOpen or shon in Knock Sensor (KS) circuitKnock Sensor (KS)ECM/PCt\411-130
P033s{4}Crankshaft PositionSensor CircuitCrankshaft Position SensorCrankshaft Positaon Sensor circuitE Cl\,l/PC l\,'!11-131
P0336(4)Crankshaft Position SensorRange/PerformanceCrankshaft Position SensorTiming belt skipped teeth11,131
P0420{67)Catalyst System Efficiency BelowThresholdThree Way Catalytic convenerSecondary HO2S {Sensor 2)'t1-200
P0441*3 (92)
Evaporative EmissionControlSystemInsulficient Purge Flow
EVAP Purge Control Solenoid valveEVAP Purge Control Solenoid valve circuitThrottle gody (purge port)TubingPCM
'It 205
P0451*5FuelTank Pressure Sensor CircuitBange/PerformanceFuel Tank Pressure SensorECM/PCMt't-208
(91iFuel Tank Pressure SensorCirclit Low InputOpsn orShort in FuelTank Pressure Sensor circuitFuel Tank Pressure SensorECM/PCt\411-209
P0453*r.5 {91)FuelTank Pressure Sensor CircuitHigh InputOpen in Fuel Tank Pressure Sensor circuitFuel Tank Pressure SensorECt /PCt\.111-211
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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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