The control module detected that the air-fuel mixture stayed richer than the target despite full corrective control (Fuel Control System B).
TuningBot DTC Database · v4.37.15
P21FD Fuel Control System B Too Rich at Higher Load Bank 1
Generic (OBD-II) interpretation in the TuningBot DTC database.
What P21FD means
Related and nearby codes
How to read P21FD
Powertrain: engine, transmission and driveline systems.
Generic SAE-standard code: same meaning on every make.
Specific fault index within the subsystem.
Frequently asked questions about P21FD
What does P21FD mean?
Fuel Control System B Too Rich at Higher Load Bank 1. The control module detected that the air-fuel mixture stayed richer than the target despite full corrective control (Fuel Control System B).
Is P21FD generic or manufacturer-specific?
P21FD is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P21FD 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: Diagnostic Strategy and DTC Logic
