TuningBot DTC Database · v4.37.15
Generic (OBD-II) interpretation in the TuningBot DTC database.
The control module detected that the air-fuel mixture stayed richer than the target despite full corrective control (Fuel Control System B).
Powertrain: engine, transmission and driveline systems.
Generic SAE-standard code: same meaning on every make.
Specific fault index within the subsystem.
Fuel Control System B Too Rich at Idle Bank 1. The control module detected that the air-fuel mixture stayed richer than the target despite full corrective control (Fuel Control System B).
P21F9 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
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.
Understand the system behind this code: Diagnostic Strategy and DTC Logic
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