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 wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P043000Catalyst System Efficiency Below Threshold Bank 2Manufacturer communications
3Original wording in English
TOYOTA
Reported code forms P043000
Some 2023 – 2024 model year Sequoia Hybrid and 2022 – 2024 model year Tundra and Tundra Hybrid vehicles may exhibit lack of power during acceleration and/or a MIL ON condition with one or more of the following…
TOYOTA
Reported code forms P043000
TSB: Some 2023 model year Sequoia Hybrid and 2022 ? 2023 model year Tundra and Tundra Hybrid vehicles may exhibit poor acceleration and/or a MIL ON condition with one or more of the following Diagnostic Trouble Codes…
TOYOTA
Reported code forms P043000
TT: Some 22MY Tundra/HV vehicles may experience a MIL ON w/DTC(s) P017400, P043000. Other symptoms of this issue include poor acceleration. A lean condition may cause damage to the internal catalyst in the catalytic…
Check vehicle applicability
3A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
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.