The 2019 Smart ForTwo is the final year of a quirky city car with a troublesome dual-clutch transmission and expensive European parts costs. Electric versions are simpler and more reliable, but the turbocharged gas models share the platform's cramped engine bay and complexity.
Dual-Clutch Transmission (DCT) Mechatronic Failure
Common · high severityTypical onset: 40,000-80,000 mi
Symptoms: Harsh shifting or refusal to engage gears, Check engine light with transmission codes (P17xx range), Lurching or stalling when coming to a stop, Grinding or clunking during shifts
Fix: Mechatronic unit controls clutch actuation and fails due to overheating and internal solenoid wear. Replacement requires transmission removal, 8-12 labor hours. OEM unit required, aftermarket rarely works. TCM reprogramming mandatory after install.
Estimated cost: $3,500-5,500
Transmission Oil Cooler Line Leaks
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Transmission fluid puddles under front of car, Low fluid warning or erratic shifting, Visible fluid on radiator support or frame rail, Burnt transmission fluid smell
Fix: Plastic quick-connect fittings on cooler lines crack from heat cycling. Lines run tight against engine block. Requires bumper removal for access, 3-5 hours labor. Must use OEM lines—aftermarket fittings fail quickly. Fluid flush recommended after repair.
Estimated cost: $600-1,200
Cylinder Head Gasket Failure (0.9L Turbo)
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: White smoke from exhaust on startup, Coolant loss with no visible leaks, Overheating or temperature fluctuations, Milky oil on dipstick or oil cap
Fix: Three-cylinder engine runs hot and gasket fails between cylinders 2-3. Requires engine removal in this chassis due to packaging—no room to work. 12-16 hours labor. Head resurfacing usually needed. Timing chain and water pump should be done while apart.
Estimated cost: $3,000-4,800
LED Headlight Module Moisture Intrusion
Common · low severitySymptoms: Condensation visible inside headlight lens, Intermittent headlight failure or flickering, Bulb-out warning despite working bulbs, Corroded LED driver board visible when inspected
Fix: Headlight seals fail prematurely, allowing moisture into LED modules. Cannot reseal—entire assembly requires replacement. 1-2 hours per side but parts are $600-900 EACH from dealer. Aftermarket units available but quality inconsistent. Some owners live with condensation if lights still function.
Estimated cost: $800-2,000
Engine Bay Fuse Box Corrosion
Occasional · medium severitySymptoms: Random electrical gremlins (wipers, windows, HVAC), No-start condition with multiple fault codes, Blown fuses in same positions repeatedly, Green corrosion visible on fuse terminals
Fix: Fuse box sits low in front bumper area, exposed to road spray. Drain holes clog, water pools inside. Individual fuse slots corrode. Cannot replace slots—entire box needed at $400-700 parts alone. 2-3 hours labor to swap. Cleaning and dielectric grease buys time but corrosion returns.
Estimated cost: $700-1,200
Transmission Mount Collapse
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Excessive vibration at idle in gear, Clunking when accelerating or reversing, Visible engine movement when revving, Transmission feels like it's hitting something during shifts
Fix: Lower transmission mount fails from DCT heat and vibration. Rubber separates from metal bracket. Access requires removal of belly pan and exhaust heat shield. 2-3 hours labor. OEM mount mandatory—aftermarket versions soften too quickly. Check engine mounts at same time.
Estimated cost: $400-700
Buy the electric version if you must own one—gas models with the DCT are expensive nightmares after 60k miles, and parts availability is declining as Mercedes-Benz exits the brand.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.