Fault code P0204 – a step-by-step guide to diagnosing and fixing it

Error code P0204 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected a defect in the injection valve of the second cylinder. This DTC P0204 indicates problems in the fuel injection system which can lead to uneven fuel distribution.

What causes can this error code have?

• Defective injection valve cylinder 2
• Damaged cable to the injection nozzle
• Loose or corroded plug connections
• Defective engine control unit output stage
• Short circuit in the wiring
• Clogged injection nozzle
• Defective fuel pump with insufficient pressure
• Dirty fuel filter

What symptoms occur in parallel with fault code P0204?

• Engine running unevenly: The engine runs unevenly, especially at idling speed
• Power loss: Noticeably reduced engine power when accelerating
• Starting problems: The vehicle starts poorly or takes several attempts
• Increased fuel consumption: Consumption increases noticeably
• Misfiring: Irregular ignition in the second cylinder
• Exhaust odor: Unburned fuel in the exhaust gas

How to fix the problem of error code P0204?

• The repair requires a systematic diagnosis of the injection system. Here are the most important solutions:
• Replace injection valve cylinder 2 and then check the system for correct function
• Check the wiring to the injection valve completely and replace damaged cables
• Clean plug connections, treat with contact spray and connect firmly
• Diagnose the engine control unit output stage and replace the control unit if defective
• Flush the fuel system and have the clogged injection nozzle professionally cleaned
• Replace fuel filter and check fuel pump for correct pressure
• Perform a multimeter test of the electrical voltage at the injection valve