What causes the P0304 code?

Failed coil pack on cylinder 4; Faulty wiring harness connecting the respective sensor; Aging electrical connections or corrosion due to environmental elements specific to mercedes vehicles.

How to fix the P0304 code?

Conduct a complete OBD2 scan. Inspect the engine bay for loose connections related to Cylinder 4 Misfire Detected. Replace failed components with genuine OEM mercedes parts to ensure the fault does not return. Clear the ECU memory afterwards.

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Mercedes-Benz

🟡 Medium

P0304

MERCEDES P0304 Cylinder 4 Misfire Detected

The P0304 diagnostic trouble code indicates an issue with the Cylinder 4 Misfire Detected. A frequent issue on Mercedes-Benz powertrains, often related to failed coil pack on cylinder 4. Found frequently across mercedes models utilizing OM651, M274, OM642 engines, this code will illuminate the Check Engine Light and may cause the vehicle to enter Limp Mode to protect the mechanical components.

Brand

Mercedes-Benz

Fault Code

P0304

Severity

🟡 Medium

Models

A/B/C/E/S Class, GLC, GLE, GLA, CLA, Vito, Sprinter

🛠️ Diagnostic Overview

Difficulty Level

🛠️🛠️🛠️ Hard (Advanced)

Estimated Time

⏱️ 3-6 Hours

🧰 Required Tools

✓ Digital Multimeter
✓ OBD2 Diagnostic Scanner
✓ Socket Wrench & Hand Tools
✓ Electrical Contact Cleaner Spray

⚠️ Possible Causes

• Failed coil pack on cylinder 4
• Faulty wiring harness connecting the respective sensor
• Aging electrical connections or corrosion due to environmental elements specific to mercedes vehicles.

🔧 Recommended Fixes

→ Conduct a complete OBD2 scan. Inspect the engine bay for loose connections related to Cylinder 4 Misfire Detected. Replace failed components with genuine OEM mercedes parts to ensure the fault does not return. Clear the ECU memory afterwards.

🚗 Commonly Affected Vehicles