HINO
Reported code forms P0421
SB-14-012 A subject vehicle may exhibit an illuminated check engine lamp with DTC (Diagnostic Trouble Code) P0421 (Catalyst efficiency below threshold). The engine ECU may falsely detect an issue with the ATC (After…
HomeP0421 · Manufacturer communications
P0421 · Manufacturer communications
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
MITSUBISHI
Reported code forms P0421
Due to variations in production, certain exhaust manifold mounted catalytic converters may experience catalyst layer separation on affected vehicles. If this occurs, the MIL will illuminate with DTC P0421 or P0431,…
MITSUBISHI
Reported code forms P0421
DIAGNOSTIC TROUBLE CODE (DTC) P0421 / DTC P0431. MITSUBISHI TECH TALK. *TT
MITSUBISHI
Reported code forms P0421
MALFUNCTION INDICATOR LAMP (MIL) ON AND DIAGNOSTIC TROUBLE CODE (DTC) P0421. *TT
AUDI
Reported code forms P0421
SUBJECT REGARDING MALFUNCTION INDICATOR LIGHT (MIL) ON, DIAGNOSTIC TROUBLE CODES P0421 OR P0431 STORED IN MEMORY. *TT
MAZDA
Reported code forms P0421
SUBJECT REGARDING MALFUNCTION INDICATOR LIGHT (MIL) ILLUMINATION W/DTC P0421. *YC
MAZDA
Reported code forms P0421
SUBJECT REGARDING MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATION WITH DTC P0421. *YC
MAZDA
Reported code forms P0421
SOME VEHICLES MAY EXHIBIT A MALFUNCTION INDICATOR LIGHT (MIL) ILLUMINATED WITH DIAGNOSTIC TROUBLE CODE (DTC) P0421 STORED. *YC
FORD
Reported code forms P0421
MIL CODE - P0421 - DO NOT ATTEMPT REPAIRS. *TW
FORD
Reported code forms P0421
2.0L WITH THE MIL ON AND CODE P0421. *JD