Fault code P0266 – a step-by-step guide to diagnosing and fixing it

Error code P0266 is displayed and the check engine light is on - what does this mean?

The OBD system detects a fault in the injector of cylinder 2, which is classified as "Cylinder 2 Injector Circuit Low". This DTC P0266 trouble code indicates a problem with the electrical circuit of the fuel injector, where the voltage is below the expected value.

What can cause this error code?

• Defective injector in cylinder 2
• Damaged wiring to the injector
• Corroded or loose plug connections
• Defective engine control unit (ECU)
• Short circuit in the injector circuit
• Defective fuel pump or low fuel pressure
• Clogged fuel filter

What symptoms occur in parallel with fault code P0266?

• Engine running unsteadiness: The engine runs unevenly or jerks when idling
• Loss of power: Noticeable reduction in engine power, especially under load
• Increased fuel consumption: The vehicle consumes more fuel than usual
• Starting problems: Difficulty starting the engine, especially in cold weather
• Exhaust problems: Black or white smoke from the exhaust
• Misfiring: Irregular combustion in cylinder 2

How to fix the problem of error code P0266?

• The repair requires a systematic approach to identify the exact cause.
• Check the injector resistance and, if defective, replace the injector of cylinder 2 completely, as a defective injector is the most common cause of this fault code
• Check the wiring and plug connections to the injector thoroughly, repair damaged cables and clean or replace corroded contacts
• Measure the fuel pressure and replace the fuel pump or fuel filter if the pressure is low to ensure a proper fuel supply
• Perform ECU diagnostics and, if necessary, reprogram or replace the engine control unit if other components are OK
• Carry out injector cleaning with professional cleaning agents and then test the function to remove blockages
• Flush the entire fuel system and replace all filters if contamination in the system is the cause