P0212
Injector Circuit/Open - Cylinder 12
If your vehicle's onboard computer has flagged the diagnostic trouble code P0212, it refers to a detected anomaly regarding "Injector Circuit/Open - Cylinder 12". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
A P0212 fault code points directly to a problem with injector circuit/open - cylinder 12 that the ECM has confirmed over multiple drive cycles. The most common signs are misfire code on v12 engine, rich or lean exhaust smell. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Misfire code on V12 engine, rich or lean exhaust smell
Common Causes
- Defective Cylinder 12 fuel injector
- Open ground circuit to injector
- Failed PCM driver
- Corrosion in wiring harness
How to Fix
- 1 Replace Cylinder 12 injector
- 2 Trace and repair ground wire
- 3 Test PCM
- 4 Replace affected wiring section
Technical Explanation
P0212 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. Once confirmed, the code is stored as a permanent DTC and the MIL is activated. The freeze frame snapshot — recording RPM, load, coolant temperature, and fuel trim at fault detection — is also saved and is critical for accurate diagnosis.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including defective cylinder 12 fuel injector — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
Before replacing any component on P0212, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Injector replacement: 200 - 500