What does code P21EC mean?

Q: What does code P21EC mean?

Cylinder 9 Injector B Circuit Low. P21EC indicates that the powertrain control module (PCM) has detected an abnormally low voltage on the control circuit for injector B of cylinder 9, which usually means the circuit is shorted to ground or the injector's internal coil has failed. The PCM commands a fuel pulse but sees the circuit voltage stay below the expected threshold, so it sets this code and may disable fuel delivery to that cylinder to protect the engine and catalytic converter.

DTC codes / P21xx · Fuel and air metering / P21EC

P21ECCylinder 9 Injector B Circuit Low

P21EC indicates that the powertrain control module (PCM) has detected an abnormally low voltage on the control circuit for injector B of cylinder 9, which usually means the circuit is shorted to ground or the injector's internal coil has failed. The PCM commands a fuel pulse but sees the circuit voltage stay below the expected threshold, so it sets this code and may disable fuel delivery to that cylinder to protect the engine and catalytic converter.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

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.