The control module detected a fault associated with the Clogged Or Dirty Catalyst circuit or function; the stored code identifies the affected component rather than a single failure mode. This is the manufacturer-specific definition used by Mitsubishi.
TuningBot DTC Database · v4.37.15
P1421 Mitsubishi - Clogged Or Dirty Catalyst
Manufacturer-specific interpretation for Mitsubishi. All interpretations of P1421
What P1421 means
Related and nearby codes
How to read P1421
Powertrain: engine, transmission and driveline systems.
Manufacturer-defined range: the meaning can differ between brands.
Specific fault index within the subsystem.
Frequently asked questions about P1421
What does P1421 mean?
Clogged Or Dirty Catalyst. The control module detected a fault associated with the Clogged Or Dirty Catalyst circuit or function; the stored code identifies the affected component rather than a single failure mode. This is the manufacturer-specific definition used by Mitsubishi.
Is P1421 generic or manufacturer-specific?
P1421 is a manufacturer-specific code. In this database it is documented for: Mitsubishi. The same number can mean something different on other brands.
Can TuningBot remove P1421 at file level?
If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.
Other file services
Understand the system behind this code: Oxygen Sensors (Lambda)
