Vehicles using OM651.930 engine list:

Engine OM651.930

Symptoms:
- Rough idling and loss of power
- Excessive smoke from exhaust (black or blue)
- Engine warning light illuminated
- Increased fuel consumption
- Difficulty starting or misfires

Diagnosis:
- Check for clogged diesel particulate filter (DPF) causing poor exhaust flow
- Inspect turbocharger for wear or failure, including shaft play and boost pressure loss
- Test fuel injectors for leaks or poor spray pattern affecting combustion
- Examine EGR (Exhaust Gas Recirculation) valve for carbon buildup restricting flow
- Scan engine control unit (ECU) for fault codes related to sensors or emissions systems

Fixes:
- Perform DPF regeneration or replace if severely clogged
- Repair or replace faulty turbocharger components
- Clean or replace fuel injectors to restore proper fuel delivery
- Clean or replace EGR valve to ensure correct exhaust gas recirculation
- Update ECU software if available to improve engine management and emissions control
- Replace worn glow plugs to aid cold starts in diesel engines

Prevention:
- Use high-quality diesel fuel and adhere to recommended oil change intervals with correct oil grade
- Avoid frequent short trips that prevent DPF regeneration; allow engine to reach operating temperature regularly
- Regularly inspect and clean air intake and EGR systems to prevent carbon buildup
- Follow manufacturer service schedules for fuel system and emissions components
- Monitor warning lights promptly and address issues early to avoid costly repairs

By maintaining these practices, owners of Mercedes Benz vehicles equipped with the OM651.930 engine can reduce common issues and ensure reliable performance.