P2146 Injector Group A Supply Voltage — Causes & Fix

What Does P2146 Mean?

P2146 is a manufacturer-specific code indicating the ECU has detected a voltage fault in the power supply to injector group A. On most diesel engines, injectors are grouped in pairs — group A typically covers cylinders 1 and 4. This code usually indicates an internal ECU fault rather than an injector problem, but injector short circuits can trigger it.

P2146 at a Glance

• What it means: The ECU has detected a supply voltage fault affecting injector group A (typically cylinders 1 and 4).
• Most common cause: ECU injector driver failure, main relay fault, or wiring short.
• Severity: Serious — can affect two cylinders simultaneously.
• Can you drive?: Not recommended. Two cylinders may be disabled.
• Typical repair cost: £200-£500 for ECU repair; £100-£350 per injector if required.