What does code P21D8 mean?

Q: What does code P21D8 mean?

Cylinder 10 Injector B Circuit/Open. P21D8 is a generic OBD-II code indicating that the engine control module (ECM) has detected an open circuit or excessive resistance in the fuel injector circuit for cylinder 10, specifically the 'B' injector circuit, which may be a second injector or a secondary control wire depending on the engine design. The ECM monitors the injector driver circuit and sets this code when the commanded current does not match the expected value, often due to a wiring fault, connector issue, or failed injector.

DTC codes / P21xx · Fuel and air metering / P21D8

P21D8Cylinder 10 Injector B Circuit/Open

P21D8 is a generic OBD-II code indicating that the engine control module (ECM) has detected an open circuit or excessive resistance in the fuel injector circuit for cylinder 10, specifically the 'B' injector circuit, which may be a second injector or a secondary control wire depending on the engine design. The ECM monitors the injector driver circuit and sets this code when the commanded current does not match the expected value, often due to a wiring fault, connector issue, or failed injector.

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.