P0212 Injector Circuit Malfunction - Cylinder 12

P0212 indicates an injector circuit malfunction on cylinder 12. The injector 12 command path is electrically invalid or unreliable.

Code details

Generic OBD-II · P0

System: Injector
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace injector 12 before checking the circuit from power feed through the controller driver.

Symptoms of P0212

Check-engine light, often with a misfire feel from one cylinder.
Rough idle, hesitation, or a slight loss of power.
Higher fuel use, or in some cases a fuel smell.

Common causes of P0212

A stuck, leaking, clogged, or electrically failed injector.
Injector wiring, connector, or driver-circuit faults.
Low fuel pressure or contamination affecting injector behaviour.

Useful checks before replacing parts

Measure injector 12 feed voltage, control pulse, resistance, current if available, and connector condition under load.
Compare cylinder 12 contribution, misfire data, fuel trim response, and injector command with other cylinders.
Inspect the cylinder 12 harness branch for heat exposure, rubbed insulation, loose terminals, connector oil, and shared feed faults.

Related OBD-II codes

These nearby injector entries can help compare wording and pin down the fault area.