What does code P21BB mean?

Q: What does code P21BB mean?

Cold Start Cylinder 6 Injection Timing. P21BB indicates that the engine control module (ECM) has detected a problem with the fuel injection timing for cylinder 6 during a cold start. The ECM monitors the injection timing strategy and sets this code when the actual timing deviates from the commanded value beyond a calibrated threshold, specifically when the engine coolant temperature is low.

DTC codes / P21xx · Fuel and air metering / P21BB

P21BBCold Start Cylinder 6 Injection Timing

P21BB indicates that the engine control module (ECM) has detected a problem with the fuel injection timing for cylinder 6 during a cold start. The ECM monitors the injection timing strategy and sets this code when the actual timing deviates from the commanded value beyond a calibrated threshold, specifically when the engine coolant temperature is low.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaFuel and air metering

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.