P0266 Cylinder 2 Contribution/Balance — Causes & Fix

What Does P0266 Mean?

P0266 indicates the Engine Control Unit (ECU) has detected a power imbalance in cylinder 2. The ECU continuously monitors crankshaft acceleration after each cylinder fires — when cylinder 2 contributes noticeably less torque than the others, P0266 is set. This is almost always caused by a degraded injector that is delivering too little or too much fuel.

P0266 at a Glance

• What it means: The ECU has detected that cylinder 2 is contributing less power than the other cylinders.
• Most common cause: Worn or failing cylinder 2 injector, causing uneven fuel delivery.
• Severity: Moderate — driveable but causes rough running and increased emissions.
• Can you drive?: Yes, but performance is reduced. Address within 1–2 weeks.
• Typical repair cost: £100–£350 for injector replacement.