What does this code mean?
The controller judged catalyst performance below its threshold under the monitor's test conditions. P0420 refers to bank 1 and P0430 to bank 2. Inspect exhaust leaks and related misfire or mixture codes; assess sensor signals and the vehicle-specific catalyst test. The code alone does not prove the catalyst or an oxygen sensor needs replacement.
Sources and interpretation [1]
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer communications
6Original wording in English
LAND ROVER
Reported code forms P0420
Loss of power, rattling from underside of the vehicle and the Malfunction Indicator Lamp (MIL) illuminated on the instrument cluster. The root cause of the symptoms is the catalytic converter over temperature. The…
LAND ROVER
Reported code forms P0420-00
Customer reports that the Malfunction Indicator Lamp (MIL) is illuminated on the Instrument Cluster (IC). Diagnostic Trouble Code(s) related to Catalyst System Efficiency P0420-00 and/or P0430-00 are stored in the…
LAND ROVER
Reported code forms P0420-00
Issue: A Technician will find the following Diagnostic Trouble Code (DTC) relevant to catalyst system efficiency, P0420-00 stored in the Powertrain Control Module (PCM). The Malfunction Indicator Lamp (MIL) could also…
LAND ROVER
Reported code forms P0420-00
Issue: A Technician will find the following Diagnostic Trouble Code (DTC) relevant to catalyst system efficiency, P0420-00 stored in the Powertrain Control Module (PCM). The Malfunction Indicator Lamp (MIL) could also…
LAND ROVER
Reported code forms P0420
"SITUATION: ON VEHICLES FITTED WITH THE 4.2L SC V8 ENGINE ONLY, THE ENGINE MALFUNCTION INDICATOR LAMP (MIL) MAY BE ILLUMINATED. UPON DIAGNOSIS, THE TECHNICIAN FINDS THAT DIAGNOSTIC TROUBLE CODE P0420 AND/OR P0430 ONLY…
LAND ROVER
Reported code forms P0420
"ISSUE -REPAIR TRIGGERED DUE TO MIL LIGHT CAUSED BY DTC P0430 OR P0420. -MILEAGE: LESS THAN 80,000 MILES -NO PREVIOUS INCIDENCE OF MISFIRE DTC P03XX CAUSE: POSSIBLE FAULT WITH EXHAUST CATALYTIC CONVERTER."
Check vehicle applicability
5A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Land Rover | RANGE ROVER SPORT | 2022 |
| Land Rover | RANGE ROVER SPORT | 2021 |
| Land Rover | RANGE ROVER SPORT | 2020 |
| Land Rover | RANGE ROVER SPORT | 2018 |
| Land Rover | RANGE ROVER SPORT | 2009 |
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Sources and interpretation
These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.
- 2024–2025 MY OBD System Operation Summary for Gasoline Engines ↗
Ford Motor Company · PDF page(s) 2, 3 ·
Source check date · 2026-10-27
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.