P2149 Fuel Injector Group B Supply Voltage Circuit/Open — Causes & Fix

What Does P2149 Mean?

P2149 indicates the ECU has detected an open circuit or voltage fault in the power supply to fuel injector group B. Modern diesel ECUs group injectors into banks (Group A and Group B) for power management. When the supply voltage to group B is lost or abnormal, the ECU cannot fire those injectors properly, causing the engine to run on half its cylinders.

P2149 at a Glance

• What it means: The ECU has detected a voltage fault in the supply circuit for fuel injector group B (typically cylinders 3 and 4 on a 4-cylinder, or cylinders 4–6 on a 6-cylinder).
• Most common cause: Damaged wiring harness, corroded connectors, or failed injector(s) in group B.
• Severity: Serious — affected cylinders will not fire correctly.
• Can you drive?: Short distances only. The engine will run rough on fewer cylinders.
• Typical repair cost: £40–£350 depending on wiring vs. injector replacement.