The control module detected a fault associated with the Cold Start Cylinder 10 Injection Timing circuit or function; the stored code identifies the affected component rather than a single failure mode.
Symptoms
MIL illuminated
Possible rough running or misfire
Possible increased fuel consumption
Possible causes
Injector electrical or mechanical fault
Wiring or connector fault
Fuel supply fault
Air leak causing mixture deviation
Recommended checks
Read fuel trim / mixture adaptation values
Check injector circuits and compare cylinder balance
Powertrain: engine, transmission and driveline systems.
2
Generic SAE-standard code: same meaning on every make.
1BF
Specific fault index within the subsystem.
Frequently asked questions about P21BF
What does P21BF mean?
Cold Start Cylinder 10 Injection Timing. The control module detected a fault associated with the Cold Start Cylinder 10 Injection Timing circuit or function; the stored code identifies the affected component rather than a single failure mode.
Is P21BF generic or manufacturer-specific?
P21BF is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P21BF 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.
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