What does code P21DC mean?

Q: What does code P21DC mean?

Cylinder 1 Injector B Circuit High. P21DC indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for cylinder 1 injector B, which is typically the second injector assigned to that cylinder in a multi-injector arrangement. The PCM monitors the circuit and flags this code when the voltage exceeds the expected range, often indicating an open circuit, a short to voltage, or a faulty injector.

DTC codes / P21xx · Fuel and air metering / P21DC

P21DCCylinder 1 Injector B Circuit High

P21DC indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for cylinder 1 injector B, which is typically the second injector assigned to that cylinder in a multi-injector arrangement. The PCM monitors the circuit and flags this code when the voltage exceeds the expected range, often indicating an open circuit, a short to voltage, or a faulty 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.