What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
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.
P0421:00CATALYTIC CONVERTER SYSTEMManufacturer communications
2Original wording in English
MAZDA
Reported code forms P0421 P0421:00
SOME VEHICLES MAY EXPERIENCE THE CHECK ENGINE LIGHT ON WITH DTC P0421:00 (CATALYTIC CONVERTER SYSTEM) WITH-OUT EXPERIENCING POOR ENGINE PERFORMANCE OR MISFIRE (MITSUBISHI PCM ONLY).THIS IS CAUSED BY IMPROPER CONTROL…
MAZDA
Reported code forms P0421 P0421:00
SOME VEHICLES MAY EXPERIENCE THE CHECK ENGINE LIGHT ON WITH DTC P0421:00 (CATALYTIC CONVERTER SYSTEM) WITHOUT EXPERIENCING POOR ENGINE PERFORMANCE OR MISFIRE (MITSUBISHI PCM ONLY). THIS IS CAUSED BY IMPROPER CONTROL…
Check vehicle applicability
1A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Mazda | MAZDA6 | 2016 |
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.
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.