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P0212 — Cylinder 12 Injector Circuit

Generic OBD-II · all makesPowertrain (engine & transmission)

P0212 indicates the engine control module has detected an electrical malfunction within the fuel injector circuit for cylinder 12. This fault typically involves an open circuit, short to ground, or excessive resistance preventing proper fuel delivery. The issue is isolated to the specific control path for that cylinder.

Symptoms

What causes it — most likely first

1. Failed fuel injector

The internal solenoid or coil within the cylinder 12 injector may have opened or shorted. This is the most common source of circuit codes.

2. Damaged wiring harness

Wires leading to cylinder 12 may be chafed, burned, or broken due to heat or vibration. Physical damage disrupts the electrical signal.

3. Corroded connector

The electrical plug at the injector may have corrosion or loose pins preventing connection. Moisture or age often causes terminal degradation.

4. Short circuit in wiring

The control wire may be shorted to ground or power elsewhere in the harness. This triggers immediate fault detection by the control module.

5. Faulty PCM driver

The internal transistor controlling the injector within the computer may have failed. This is rare and should only be considered after ruling out external components.

How it's diagnosed

  1. Visually inspect the wiring harness and connector at cylinder 12 for damage.
  2. Measure the resistance of the cylinder 12 injector with a multimeter.
  3. Check continuity of the wiring between the injector connector and the PCM.
  4. Swap the injector with another cylinder to see if the code follows the component.
  5. Monitor the injector control signal using an oscilloscope or noid light.
  6. Verify PCM power and ground integrity before considering module replacement.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Does this code mean I need to replace the engine computer?

No, PCM failure is very rare for this code; wiring or the injector itself is the cause in most cases.

Is it safe to drive with a P0212 code?

No, prolonged driving with a misfire can damage the catalytic converter and reduce engine safety.

Why does the code specify cylinder 12?

Modern engines monitor each injector circuit individually to isolate electrical faults to specific cylinders.