Injector Circuit/Open
Diagnostic Trouble Code P0200 indicates a general malfunction in the fuel injector circuit. The Engine Control Module (ECM) sets this code when it detects an open circuit, short circuit, or abnormal voltage/resistance in one or more of the fuel injector circuits.
This code is considered high severity because a malfunctioning fuel injector circuit can cause severe engine misfires, stalling, or a no-start condition, potentially leaving you stranded or damaging the catalytic converter.
Common symptoms
- Illuminated Check Engine Light
- Engine misfires or runs rough
- Lack of engine power or poor acceleration
- Engine stalling or hesitation
- Decreased fuel economy
Likely causes
- Faulty or damaged fuel injector wiring harness
- Loose or corroded fuel injector electrical connectors
- Defective fuel injector
- Blown fuel injector fuse or faulty relay
- Internal failure in the Engine Control Module (ECM)
What to check before replacing parts
Visually inspect the fuel injector wiring harness and connectors.
Look for: Look for frayed wires, melted insulation, loose connections, or corrosion at the injector plugs that could cause an open or short circuit.
Check the fuel injector fuses and relays.
Look for: Test for blown fuses or a faulty relay that supplies power to the injector circuit. A blown fuse often indicates a short circuit.
Measure the resistance of the fuel injectors using a digital multimeter.
Look for: Compare the resistance reading of each injector to the manufacturer's specifications. An out-of-spec reading indicates a faulty injector coil.
Test for power and ground at the fuel injector connectors.
Look for: With the key on or engine cranking, verify that each injector receives proper battery voltage and a pulsing ground signal from the ECM using a noid light or multimeter.
Perform a continuity test on the wiring between the injectors and the ECM.
Look for: Check for high resistance, open circuits, or shorts to ground in the wiring harness. If the wiring and injectors are good, the ECM may be suspect.
This page explains the generic P0200 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.
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