P0204 Injector Circuit Malfunction (Cylinder 4) — Causes & Fix

What Does P0204 Mean?

P0204 indicates an electrical fault in the fuel injector circuit for cylinder 4. Cylinder 4 is furthest from the timing belt on inline-four engines. This is the final cylinder in the firing order and faults here follow the same diagnostic path as P0201-P0203.

P0204 at a Glance

• What it means: The ECU has detected a fault in the fuel injector electrical circuit for cylinder 4.
• Most common cause: Faulty injector, wiring damage, or ECU driver fault.
• Severity: Moderate to serious — causes misfire on cylinder 4.
• Can you drive?: Short distances only. Prolonged driving risks DPF and catalytic converter damage.
• Typical repair cost: £100-£350 for injector replacement; £40-£100 for wiring repair.