- Install scan tool. Start engine and check if DTC P0420 is present. If DTC is present, go to next step. If DTC is not present, problem is intermittent. See INTERMITTENTS in «TESTS W/O CODES»(ref-16665) article.
- Check for exhaust leak before and after the catalytic converter. Repair as necessary. If leaks are not found, check rear HO2S. For diagnosis, see related DTC or ENGINE SENSORS & SWITCHES in «SYSTEM/COMPONENT TESTS»(ref-16639) article. Replace as necessary. If rear HO2S is okay, go to next step.
- Replace catalytic converter. Clear DTC. See CLEARING CODES under Self Diagnostic System section. Retest system. If DTC resets, replace ECM.
Home/Hyundai/Tiburon/Hyundai Tiburon I (1996-1999)/Repair manual/Testing & Diagnostics/DTC P0420 - CATALYST EFFICIENCY BELOW THRESHOLD
Contents
Wiring diagrams Section: Testing & Diagnostics- Engine Controls - System/component Tests: Overview
- Engine Controls - System/component Tests: Diagnosis
- Engine Controls - System/component Tests: Other
- Engine Controls - Tests W/codes: Diagnosis
- Engine Controls - Tests W/codes: Component Locations
- Engine Controls - Tests W/codes: Other
- DTC P0102/P0103 - MASS AIRFLOW (MAF) SENSOR CIRCUIT INPUT
- DTC P0112/P0113 - INTAKE AIR TEMPERATURE (IAT) CIRCUIT
- DTC P0116/P0117/P0118 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT
- DTC P0122/P0123: THROTTLE POSITION (TP) SENSOR CIRCUIT INPUT
- DTC P0130/P0131/P0132/P0137/P0138 - FRONT & REAR HO2S SENSOR CIRCUIT
- DTC P0133 - FRONT HO2S CIRCUIT SLOW RESPONSE
- DTC P0134/P0136 - HO2S CIRCUIT, NO ACTIVITY DETECTED
- DTC P0135/P0141 - HO2S HEATER CIRCUIT MALFUNCTION
- DTC P0201/P0202/P0203/P0204 - INJECTOR CIRCUIT MALFUNCTION
- DTC P0300 - RANDOM MISFIRE DETECTED
- DTC P0301/P0302/P0303/P0304 - CYLINDER MISFIRE DETECTED
- DTC P0326 - KNOCK SENSOR (KS) CIRCUIT RANGE
- DTC P0335/P0336 - CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT RANGE/MALFUNCTION
- DTC P0342/P0343 - CAMSHAFT POSITION (CMP) SENSOR CIRCUIT MALFUNCTION
- DTC P0420 - CATALYST EFFICIENCY BELOW THRESHOLD
- DTC P0442/P0443/P0446/P0455 - EVAP PURGE CONTROL SYSTEM
- DTC P0444/P0445 - EVAP PURGE CONTROL VALVE CIRCUIT
- DTC P0447/P0448 - EVAP VENT CONTROL VALVE CIRCUIT
- DTC P0451 - FUEL TANK PRESSURE SENSOR SIGNAL NOT VALID
- DTC P0452/P0453 - FUEL TANK PRESSURE SENSOR MALFUNCTION
- DTC P0501 - VEHICLE SPEED SENSOR (VSS) RANGE
- DTC P0506/P0507 - IDLE RPM IS NOT AS EXPECTED
- DTC P0605 - INTERNAL CONTROL MODULE ROM ERROR
- DTC P1123/P1124/P1127/P1128 - AIR/FUEL RATIO CONTROL
- DTC P1510/P1513/P1552/P1553 - IDLE SPEED CONTROL (ISC) ACTUATOR CIRCUIT
- DTC P1586 - TRANSMISSION ENCODING SIGNAL NOT RATIONAL
- DTC P1605/P1606 - ACCELERATION/ROUGH ROAD SENSOR CIRCUIT
- DTC P1611/P1614 - MIL REQUEST SIGNAL CIRCUIT
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