For diagnosis (Scheme 156)and (Scheme 157).
Home/Subaru/Impreza/Subaru Impreza GD/GC/GG facelift (2002-2005)/Repair manual/Testing & Diagnostics/DTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
Contents
Wiring diagrams Section: Testing & Diagnostics- Engine Controls - Basic Diagnostic Procedures: Diagnosis
- Engine Controls - Basic Diagnostic Procedures: Other
- Engine Controls - Trouble Shooting - No Codes: Diagnosis
- Engine Controls - Trouble Shooting - No Codes: Other
- Engine Controls - System & Component Testing: Overview
- Engine Controls - System & Component Testing: Diagnosis
- Engine Controls - System & Component Testing: Component Locations
- Engine Controls - System & Component Testing: Other
- Engine Controls - Self-Diagnostics - 2.5L: Overview
- Engine Controls - Self-Diagnostics - 2.5L: Diagnosis
- Engine Controls - Self-Diagnostics - 2.5L: Component Locations
- Engine Controls - Self-Diagnostics - 2.5L: Other
- Self-Diagnostics - 2.0L: Overview
- Self-Diagnostics - 2.0L: Diagnosis
- Self-Diagnostics - 2.0L: Component Locations
- Self-Diagnostics - 2.0L: Other
- DTC P0030: FRONT HEATED OXYGEN SENSOR (HO2S) CONTROL CIRCUIT, MALFUNCTION
- DTC P0031: FRONT HEATED OXYGEN SENSOR (HO2S) HEATER CIRCUIT, LOW INPUT
- DTC P0032: FRONT HO2S HEATER CIRCUIT, HIGH INPUT
- DTC P0037: REAR HO2S HEATER CIRCUIT, MALFUNCTION
- DTC P0038: REAR HO2S HEATER CIRCUIT, HIGH OUTPUT
- DTC P0068: INTAKE MANIFOLD/BAROMETRIC PRESSURE SENSOR CIRCUIT, RANGE PERFORMANCE PROBLEM
- DTC P0101: MASS AIR FLOW CIRCUIT, RANGE/PERFORMANCE
- DTC P0102: MASS AIR FLOW CIRCUIT, LOW INPUT
- DTC P0103: MASS AIR FLOW CIRCUIT, HIGH INPUT
- DTC P0107: INTAKE MANIFOLD/BAROMETRIC PRESSURE SENSOR CIRCUIT, LOW INPUT
- DTC P0108: INTAKE AIR TEMPERATURE & PRESSURE SENSOR CIRCUIT, HIGH INPUT
- DTC P0111: INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0112: INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT, LOW INPUT
- DTC P0113: INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT, HIGH INPUT
- DTC P0117: ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT, LOW INPUT
- DTC P0118: ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT, HIGH INPUT
- DTC P0121: THROTTLE POSITION (TP) SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0122: THROTTLE POSITION (TP) SENSOR CIRCUIT, LOW INPUT
- DTC P0123: THROTTLE POSITION (TP) SENSOR CIRCUIT, HIGH INPUT
- DTC P0125: ENGINE COOLANT TEMPERATURE TOO LOW FOR CLOSED LOOP FUEL CONTROL
- DTC P0128: THERMOSTAT MALFUNCTION
- DTC P0129: BAROMETRIC PRESSURE TOO LOW
- DTC P0130: FRONT HO2S CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0133: FRONT HO2S CIRCUIT, SLOW RESPONSE
- DTC P0137: REAR HO2S CIRCUIT, LOW INPUT
- DTC P0138 REAR HO2S CIRCUIT, HIGH INPUT
- DTC P0139: REAR HO2S CIRCUIT, SLOW RESPONSE
- DTC P0172: FUEL TRIM MALFUNCTION (TOO RICH)
- DTC P0181: FUEL TEMPERATURE SENSOR "A" CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0182: FUEL TEMPERATURE SENSOR "A" CIRCUIT, LOW INPUT
- DTC P0183: FUEL TEMPERATURE SENSOR "A" CIRCUIT, HIGH INPUT
- DTC P0230: FUEL PUMP PRIMARY CIRCUIT
- DTC P0244: TURBOCHARGER WASTEGATE SOLENOID "A" RANGE/PERFORMANCE
- DTC P0245: TURBOCHARGER WASTEGATE SOLENOID "A" LOW
- DTC P0246: TURBOCHARGER WASTEGATE SOLENOID "A" HIGH
- DTC P0301, P0302, P0303 & P0304: CYLINDERS NO. 1-4 MISFIRE DETECTED
- DTC P0327: KNOCK SENSOR (KS) CIRCUIT, LOW INPUT
- DTC P0328: KNOCK SENSOR (KS) CIRCUIT, HIGH INPUT
- DTC P0335: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT, MALFUNCTION
- DTC P0336: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0340: CAMSHAFT POSITION (CMP) SENSOR CIRCUIT, MALFUNCTION
- DTC P0341: CAMSHAFT POSITION (CMP) SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
- DTC P0442: EVAP SYSTEM PURGE CONTROL VALVE CIRCUIT, MALFUNCTION
- DTC P0447: EVAP SYSTEM VENT CONTROL CIRCUIT, LOW INPUT
- DTC P0448: EVAP SYSTEM VENT CONTROL CIRCUIT, HIGH INPUT
- DTC P0451: EVAP SYSTEM PRESSURE SENSOR RANGE/PERFORMANCE PROBLEM
- DTC P0452: EVAP SYSTEM PRESSURE SENSOR LOW INPUT
- DTC P0453: EVAP SYSTEM PRESSURE SENSOR HIGH INPUT
- DTC P0456: EVAP SYSTEM MALFUNCTION
- DTC P0457: EVAP SYSTEM LEAK DETECTED (FUEL CAP LOOSE/OFF)
- DTC P0458: EVAP SYSTEM PURGE CONTROL VALVE CIRCUIT, LOW INPUT
- DTC P0459: EVAP SYSTEM PURGE CONTROL VALVE CIRCUIT, HIGH INPUT
- DTC P0461: FUEL LEVEL SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM
- DTC P0462: FUEL LEVEL SENSOR CIRCUIT, LOW INPUT
- DTC P0463: FUEL LEVEL SENSOR CIRCUIT, HIGH INPUT
- DTC P0464: FUEL LEVEL SENSOR INTERMITTENT INPUT
- DTC P0483: COOLING FAN FUNCTION PROBLEM
- DTC P0502: VEHICLE SPEED SENSOR CIRCUIT, LOW INPUT
- DTC P0503: VEHICLE SPEED SENSOR INTERMITTENT/ERRATIC/HIGH
- DTC P0506: IDLE CONTROL SYSTEM RPM LOWER THAN EXPECTED
- DTC P0507: IDLE CONTROL SYSTEM RPM HIGHER THAN EXPECTED
- DTC P0508: IDLE CONTROL SYSTEM CIRCUIT, LOW
- DTC P0509: IDLE CONTROL SYSTEM CIRCUIT, HIGH
- DTC P0512: STARTER REQUEST CIRCUIT
- DTC P0519: IDLE AIR CONTROL CIRCUIT, SYSTEM PERFORMANCE
- DTC P0545: EXHAUST GAS TEMPERATURE SENSOR CIRCUIT, LOW (BANK 1)
- DTC P0546: EXHAUST GAS TEMPERATURE SENSOR HIGH (BANK 1)
- DTC P0565: CRUISE CONTROL ON SIGNAL
- DTC P0604: INTERNAL CONTROL MODULE MEMORY CHECK SUM ERROR
- DTC P0691: COOLING FAN 1 CONTROL CIRCUIT, LOW INPUT
- DTC P0692: COOLING FAN 1 CONTROL CIRCUIT, HIGH INPUT
- DTC P0703: BRAKE SWITCH INPUT MALFUNCTION
- DTC P0734: GEAR 4 INCORRECT RATIO (A/T)
- DTC P0741: TORQUE CONVERTER CLUTCH CIRCUIT, PERFORMANCE OR STUCK OFF (A/T)
- DTC P0851: NEUTRAL SWITCH INPUT CIRCUIT, LOW (A/T)
- DTC P0851: NEUTRAL SWITCH INPUT CIRCUIT, LOW (M/T)
- DTC P0852: NEUTRAL SWITCH INPUT CIRCUIT, HIGH (A/T)
- DTC P0852: NEUTRAL SWITCH INPUT CIRCUIT, HIGH (M/T)
- DTC P0864: TCM COMMUNICATION CIRCUIT, RANGE/PERFORMANCE
- DTC P0865: TCM COMMUNICATION CIRCUIT, LOW INPUT
- DTC P0866: TCM COMMUNICATION CIRCUIT, HIGH INPUT
- DTC P1086: TUMBLE GENERATED VALVE POSITION SENSOR 2 CIRCUIT, LOW
- DTC P1087: TUMBLE GENERATED VALVE POSITION SENSOR 2 CIRCUIT, HIGH
- DTC P1088: TUMBLE GENERATED VALVE POSITION SENSOR 1 CIRCUIT, LOW
- DTC P1089: TUMBLE GENERATED VALVE POSITION SENSOR 1 HIGH
- DTC P1090: TUMBLE GENERATED VALVE SYSTEM 1 (VALVE OPEN)
- DTC P1091: TUMBLE GENERATED VALVE SYSTEM 1 (VALVE CLOSE)
- DTC P1092: TUMBLE GENERATED VALVE SYSTEM 2 (VALVE OPEN)
- DTC P1093: TUMBLE GENERATED VALVE SYSTEM 2 (VALVE CLOSE)
- DTC P1094: TUMBLE GENERATED VALVE SIGNAL 1 CIRCUIT, MALFUNCTION (OPEN)
- DTC P1095: TUMBLE GENERATED VALVE SIGNAL 1 CIRCUIT, MALFUNCTION (SHORT)
- DTC P1096: TUMBLE GENERATED VALVE SIGNAL 2 CIRCUIT, MALFUNCTION (OPEN)
- DTC P1097: TUMBLE GENERATED VALVE SIGNAL 2 CIRCUIT, MALFUNCTION (SHORT)
- DTC P1110: ATMOSPHERIC PRESSURE SENSOR CIRCUIT, LOW INPUT
- DTC P1111: ATMOSPHERIC PRESSURE SENSOR CIRCUIT, HIGH INPUT
- DTC P1134: FRONT HO2S MICRO-COMPUTER PROBLEM
- DTC P1152: OXYGEN SENSOR CIRCUIT, RANGE/PERFORMANCE LOW (FRONT SENSOR, BANK 1)
- DTC P1153: OXYGEN SENSOR CIRCUIT, RANGE/PERFORMANCE HIGH (FRONT SENSOR, BANK 1)
- DTC P1400: FUEL TANK PRESSURE CONTROL SOLENOID VALVE CIRCUIT, LOW INPUT
- DTC P1420: FUEL TANK PRESSURE CONTROL SOLENOID VALVE CIRCUIT, HIGH INPUT
- DTC P1443: EVAP SYSTEM VENT CONTROL FUNCTION PROBLEM
- DTC P1446: FUEL TANK SENSOR CONTROL VALVE CIRCUIT, LOW INPUT
- DTC P1447: FUEL TANK SENSOR CONTROL VALVE CIRCUIT, HIGH INPUT
- DTC P1448: FUEL TANK SENSOR CONTROL VALVE RANGE/PERFORMANCE PROBLEM
- DTC P1544: EXHAUST TEMPERATURE TOO HIGH
- DTC P1560: BACK-UP VOLTAGE CIRCUIT, MALFUNCTION
- DTC P1698: ENGINE TORQUE CONTROL CUT SIGNAL CIRCUIT, LOW INPUT
- DTC P1699: ENGINE TORQUE CONTROL CUT SIGNAL CIRCUIT, HIGH INPUT
- DTC P1711: ENGINE TORQUE CONTROL SIGNAL NO. 1 CIRCUIT, MALFUNCTION (A/T)
- DTC P1712: ENGINE TORQUE CONTROL SIGNAL NO. 2 CIRCUIT, MALFUNCTION (A/T)
- Abbreviations
- Accessory Drive Belts
- Adjustments
- Airbag
- Anti-Lock/traction Control
- Application
- Automatic Trans
- Axle Shafts
- Basic Trouble Shooting
- Blowers, Superchargers & Turbochargers
- Brakes
- Cabin Air Filter
- Charging System
- Check Lists
- Clutches Manual & Hydraulic
- Computer Relearn
- Cooling Fan
- Cooling System (Mechanical)
- Cruise Control Systems
- Diagnostic Connector Locations
- Differentials & Drive Axles
- Door Locks & Anti-Theft Systems
- Driveline/axles
- Driveshaft & Universal Joints
- DTC Index
- Electrical Component Locations
- Emission Applications
- Engine
- Engine Performance
- Entertainment Systems
- Exhaust
- Exterior/interior Trim
- Fuel System
- Fuses & Circuit Breakers
- Gauges & Instrument Panels
- General Servicing - All Makes
- Heated Glass/defoggers
- Hoist/jack
- Horns
- Identification
- Ignition System
- Lubrication System
- Manual & Power Steering
- Manual HVAC System
- Manual Trans
- Mechanical
- Mechanical - Hydraulic
- Metric Conversions
- Mirrors
- Mode 6
- Oem General Information
- Passive Restraints
- Pin Voltage Charts
- Removal & Installation
- Restraints
- Seats
- Specifications
- Starter
- Steering
- Steering Column Switches
- Suspension Front
- Suspension Rear
- Testing & Diagnostics
- Theory & Operation
- Timing Belt
- Traction Control Disable
- Transfer Case
- Transmission
- Wheel & Tire System
- Wheel Alignment
- Windows
- Wiper/washer Systems
