Note. Specific DTC testing for catalyst efficiency is not available from manufacturer.
Home/Hyundai/Sonata/Hyundai Sonata IV (1998-2001)/Repair manual/Testing & Diagnostics/DTC P0421: CATALYST EFFICIENCY BELOW THRESHOLD
Contents
Wiring diagrams Section: Testing & Diagnostics- Engine Controls - Basic Diagnostic Procedures: Diagnosis
- Engine Controls - Basic Diagnostic Procedures: Other
- Engine Controls - Self-Diagnostics - Introduction: Overview
- Engine Controls - Self-Diagnostics - Introduction: Diagnosis
- Engine Controls - Self-Diagnostics - Introduction: Component Locations
- Engine Controls - Self-Diagnostics - Introduction: Other
- Engine Controls - Self-Diagnostics - Tests (2.4L): Overview
- Engine Controls - Self-Diagnostics - Tests (2.4L): Diagnosis
- DTC P0101, P0102, P0103: MASS AIRFLOW (MAF) SENSOR CIRCUIT MALFUNCTION
- DTC P0110: INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT MALFUNCTION
- DTC P0115, P0116, P0125: ENGINE COOLANT TEMPERATURE (ECT) SENSOR
- DTC P0120, P0121, P0123: THROTTLE POSITION (TP) SENSOR
- DTC P0130, P0132, P0135, P0136, P0139, P0140, P0141: HEATED OXYGEN SENSOR (HO2S)
- DTC P0171, P0172: FUEL TRIM MALFUNCTION
- DTC P0201 - P0204: CYLINDERS NO. 1-4 INJECTOR CIRCUIT MALFUNCTION
- DTC P0300: RANDOM MISFIRE DETECTED
- DTC P0301 - P0304: CYLINDERS NO. 1-4 MISFIRE DETECTED
- DTC P0325: KNOCK SENSOR
- DTC P0335: CRANKSHAFT POSITION (CKP) SENSOR MALFUNCTION
- DTC P0340: CAMSHAFT POSITION (CMP) SENSOR MALFUNCTION
- DTC P0401, P0403: EGR FLOW OR CIRCUIT MALFUNCTION
- DTC P0421: CATALYST EFFICIENCY BELOW THRESHOLD
- DTC P0442, P0455: EVAP SYSTEM LEAK DETECTED
- DTC P0443: EVAP SYSTEM PURGE CONTROL VALVE CIRCUIT MALFUNCTION
- DTC P0446: EVAP VENT CONTROL VALVE MALFUNCTION
- DTC P0451, P0452, P0453: EVAP FUEL TANK PRESSURE (FTP) SENSOR MALFUNCTION
- DTC P0500: VEHICLE SPEED SENSOR (VSS) MALFUNCTION
- DTC P0506, P0507: IDLE SPEED CONTROL (ISC) ACTUATOR MALFUNCTION
- DTC P0510: CLOSED THROTTLE POSITION (IDLE) SWITCH MALFUNCTION
- DTC P1100, P1102, P1103: MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR MALFUNCTION
- DTC P1521: POWER STEERING PRESSURE (PSP) SWITCH MALFUNCTION
- Engine Controls - Self-Diagnostics - Tests (2.5L): Overview
- Engine Controls - Self-Diagnostics - Tests (2.5L): Diagnosis
- DTC P0100, P0101: MASS AIRFLOW (MAF) MALFUNCTION
- DTC P0230: FUEL PUMP CIRCUIT MALFUNCTION
- DTC P0301, P0302, P0303, P0304, P0305, P0306: CYLINDERS 1-6 MISFIRE DETECTED
- DTC P0350, P0351, P0352, P0353, P0354, P0355, P0356: IGNITION COIL PRIMARY/SECONDARY CIRCUIT MALFUNCTION
- DTC P0446, P1440: EVAP SYSTEM VENT CONTROL MALFUNCTION
- DTC P0500: VEHICLE SPEED SENSOR (VSS) MALFUNCTION
- DTC P1134, P1154: HO2S CIRCUIT TRANSITION SWITCH TIME MALFUNCTION/SLOP
- DTC P1166, P1167: HO2S CONTROLLER ADAPTATION DIAGNOSIS MALFUNCTION
- DTC P1168, P1169: HO2S HEATER INCORRECT POWER SUPPLY
- DTC P1372: SEGMENT TIME ACQUISITION INCORRECT
- DTC P1443: EVAP SYSTEM FUEL TANK FILLER CAP MISSING
- DTC P1529: CUSTOMER SNAPSHOT (MIL REQUEST/FREEZE FRAME) REQUEST VIA COMMUNICATION AREA NETWORK (CAN)
- DTC P1602: SERIAL COMMUNICATION PROBLEM WITH TCM (TIME OUT)
- DTC P1616: MAIN RELAY MALFUNCTION
- DTC P1623: DIAGNOSTIC LAMP POWER STAGE MALFUNCTION
- DTC P1624, P1625: COOLING FAN RELAY CIRCUIT MALFUNCTION
- Engine Controls - Trouble Shooting - No Codes: Diagnosis
- Engine Controls - Trouble Shooting - No Codes: Other
- Abbreviations
- Accessory Drive Belts
- Adjustments
- Airbag
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