Injector Circuit/Open Cylinder 5
Diagnostic trouble code P0205 indicates that the Powertrain Control Module (PCM) has detected a malfunction, specifically an open circuit or abnormal resistance, in the fuel injector circuit for cylinder 5. The PCM monitors the voltage and resistance of the injector circuit and sets this code when the readings fall outside the expected operating range.
This code is considered high severity because a malfunctioning fuel injector will cause a severe engine misfire. Driving with a dead cylinder can lead to poor performance, stalling, and potential damage to the catalytic converter from unburned fuel if the injector is stuck open, though an open circuit usually means no fuel is delivered.
Common symptoms
- Illuminated or flashing Check Engine Light
- Engine misfire and rough idle
- Noticeable lack of engine power during acceleration
- Decreased fuel economy
- Engine stalling or hesitation
Likely causes
- Faulty fuel injector on cylinder 5
- Damaged, broken, or shorted wiring in the cylinder 5 injector circuit
- Loose or corroded electrical connector at the cylinder 5 fuel injector
- Open circuit in the fuel injector harness
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Inspect the electrical connector and wiring harness at the cylinder 5 fuel injector.
Look for: Look for loose connections, broken wires, melted insulation, or corrosion on the terminals that could cause an open circuit.
Listen to the cylinder 5 fuel injector with a mechanic's stethoscope while the engine is running.
Look for: Listen for a steady, rhythmic clicking sound. A lack of clicking indicates the injector is not firing, either due to a bad injector or lack of electrical signal.
Test the resistance of the cylinder 5 fuel injector using a digital multimeter.
Look for: Disconnect the injector and measure the resistance across its terminals. Compare the reading to the manufacturer's specifications; an infinite reading indicates an internal open in the injector.
Check for voltage and ground signals at the cylinder 5 injector connector using a noid light or multimeter.
Look for: With the engine cranking or running, a noid light should flash, indicating the PCM is sending the ground pulse. A multimeter should show battery voltage on the supply wire with the key on.
Perform a continuity test on the wiring between the injector connector and the PCM.
Look for: Check for high resistance or an open circuit (infinite resistance) in the control wire and the power supply wire. This confirms if the harness is the source of the open circuit.
This page explains the generic P0205 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.