What does code P21D7 mean?

Q: What does code P21D7 mean?

Cylinder 9 Injector B Circuit/Open. P21D7 indicates that the powertrain control module has detected an open circuit or excessive resistance in the fuel injector circuit for cylinder 9, specifically on the control wire it labels 'B'. The computer monitors the injector driver and sees that the expected current flow is missing when the injector should be firing, which sets this code and usually disables that injector.

DTC codes / P21xx · Fuel and air metering / P21D7

P21D7Cylinder 9 Injector B Circuit/Open

P21D7 indicates that the powertrain control module has detected an open circuit or excessive resistance in the fuel injector circuit for cylinder 9, specifically on the control wire it labels 'B'. The computer monitors the injector driver and sees that the expected current flow is missing when the injector should be firing, which sets this code and usually disables that injector.

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.