Mercedes-Benz C-Class W204 C220 CDI — Delphi Piezo Injector Failure
Early OM651 engines (2008-2012) were fitted with Delphi piezoelectric injectors that failed so frequently it resulted in a massive global recall and class-action lawsuits.
Severity
CriticalDIY Difficulty
Professional Only
Est. Cost
Varies
OBD Codes
P0201P0202P0203P0204Injectors
Typical layout and location for the Injectors assembly.
Symptoms
- Sudden entry into limp home mode
- Check Engine Light on
- Car dropping to 3 cylinders
- Smell of raw diesel
- P0201 to P0204 fault codes
Root Cause
Internal electrical shorts inside the Delphi piezo injectors. The ECU detects the short and immediately shuts down the affected cylinder to prevent engine damage.
How To Fix
- Check if the vehicle had the Mercedes-Benz factory recall performed.
- Mercedes replaced all four Delphi piezo injectors with more reliable Bosch solenoid injectors, which also required a new ECU and engine wiring harness.
- If it hasn't been done, the repair is extremely expensive (£2,000+).
Other Faults on This Variant
Air Conditioning Condenser Leak (Stone Damage)
MinorThe air conditioning condenser is mounted at the very front of the cooling pack, making it highly susceptible to stone damage from the road, leading to refrigerant loss.
Front Anti-Roll Bar Drop Link Wear
MinorThe front anti-roll bar drop links wear out on heavily potholed UK roads, causing an annoying knocking sound at low speeds.
Alternator / Smart Charge System Failure
SevereModern vehicles use smart charging systems to reduce engine load, but the complex regulators on the alternators frequently fail.
Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.