Smart Forfour Maintenance Plans

Smart Forfour maintenance plans vary between the 2004-2006 and 2015-2025 generations, and also by engine and fuel type. Use the selector to choose your Forfour model year range and engine so the schedule matches your car.

Select your Smart model below to view the online service schedule for your specific engine.

2 models covered

Model	Year Range	Engines covered	Fuel
Forfour 2004-2006	2004-2006	1.1 12V 75 Petrol (134.910), 1.3 16V, -LPG LPG,Petrol (135.930), 1.5 12V CDi Diesel (639.939), 1.5 16V Petrol (135.950), 1.5 Turbo BRABUS Petrol (122.950)	Diesel, LPG, Petrol
Forfour 2015-2025	2015-2025	0.9 Brabus Petrol (281.910 (H4B)), 0.9 Petrol (281.910 (H4B)), 1.0 Petrol (281.920 (H4D)), 1.0 Petrol (281.920 (H4D))	Petrol

Servicing by engine type

Petrol Smart Forfour service considerations

Petrol Forfour models span several engine families, including the 0.9 (H4B), 1.0 (H4D), 1.1 (134.910), 1.3 (135.930), and 1.5 petrol variants, plus higher-output BRABUS versions. Keep on top of routine oil and filter servicing to protect timing components and turbochargers where fitted, and replace spark plugs on schedule to avoid misfires and poor cold starting. Air filtration matters too, as restricted airflow can affect drivability and fuel economy, particularly on small-capacity engines. If your Forfour is used mainly for short trips, plan for more frequent checks of fluids and general condition between services.

Diesel Smart Forfour service considerations

The diesel Forfour (including the 1.5 12V CDi 639.939) benefits most from consistent oil-and-filter maintenance using the correct specification for the engine. Diesel systems are sensitive to intake and emissions condition, so pay attention to symptoms such as hesitant acceleration, excessive smoke, or frequent fan running, and address them early. Regular checks of air and fuel filtration help protect the turbo and high-pressure fuel system from contamination and restriction. If the car does lots of stop-start driving, it is worth being extra strict with inspections because diesel components can be less tolerant of neglected servicing.

LPG Smart Forfour service considerations

LPG Forfour variants (such as the 1.3 16V 135.930 LPG/Petrol) still need the normal petrol-engine service items, plus a few LPG-specific checks. Because LPG combustion can run hotter, keeping the ignition system in good condition (plugs, leads or coils as fitted) is important for smooth running and to reduce the chance of backfires. Plan periodic inspections for the LPG system for leaks, hose condition, and secure mounting, and keep filters (where fitted within the LPG system) maintained. If the car regularly switches between fuels, note any change in drivability between petrol and LPG, as it can help pinpoint a developing fault.

Common service operations for Smart

The operations shown below are the typical service items for a Smart Forfour, organised into a maintenance plan you can follow. Exact intervals and any additional tasks can differ by generation and engine, so always confirm the cadence for the specific Forfour you have selected.

Operation	Typical interval	Notes
Oil and filter change	See selector above	Varies by engine and recommended oil grade
Air filter	30,000 to 60,000 km	More often in urban or dusty driving
Cabin filter	15,000 to 30,000 km or 1 year	Affects air conditioning and air quality
Brake fluid	2 years (all models)	Regardless of mileage
Coolant	Per manufacturer (typically 5 years or 100,000 km)	Check level and condition (colour, deposits) at every service
Front brake pads	Depending on use (typically 30,000 to 60,000 km)	Wear depends on driving style and load carried
Timing belt	See selector above	Interval varies widely by engine
Spark plugs (petrol)	30,000 to 60,000 km	Petrol engines only

Smart electronic diagnostics

If an engine management light appears, start with an OBD2 scan to read DTCs and identify whether the issue is emissions-related, ignition/fuelling, sensor plausibility, or a misfire/air leak problem. You can look up common code meanings and next steps here: Smart Forfour OBD fault codes. Clear codes only after repairs, then recheck after a road test to confirm the fix. For intermittent faults, note freeze-frame data and the conditions when the warning occurs.