2017 SMART FORFOUR

Typical onset: 40,000-80,000 mi

Symptoms: Severe jerking during low-speed shifts, especially in stop-and-go traffic, Clunking when engaging from neutral to drive, Transmission refuses to engage gears, stranding vehicle, Warning lights for transmission system with loss of power

Fix: The Renault-sourced EDC dual-clutch is notorious for mechatronic unit failures and clutch pack wear. Most require complete transmission replacement as repairs exceed replacement cost. Expect 8-12 hours labor for R&R. Used units are risky; remanufactured preferred.

Estimated cost: $3,500-6,500

Typical onset: 50,000-90,000 mi

Symptoms: Excessive vibration at idle, especially with AC on, Clunking when shifting or accelerating, Visible engine movement when revving in park, Rattling over bumps from rear of vehicle

Fix: Rear-engine layout puts odd stress on mounts. The transmission mount (#1) and rear engine mount fail first. Access is terrible — small workspace means lots of disassembly. Budget 3-4 hours labor to replace both transmission and engine mounts together.

Estimated cost: $450-750

Typical onset: 60,000-100,000 mi

Symptoms: White smoke from exhaust on cold starts, Coolant loss with no visible leaks, Oil appears milky or coolant contaminated, Overheating under load, especially in summer heat

Fix: The 0.9L three-cylinder runs hot and tight. Head gasket failure requires cylinder head removal, resurface mandatory (warpage common), new head bolts, timing chain inspection. Rear-engine positioning makes this a 12-15 hour job. Many shops quote higher due to tight working space and special tooling for timing.

Estimated cost: $2,800-4,200

Symptoms: One or both headlights completely out, Flickering headlights, especially over bumps, Low beam works but high beam dead, or vice versa, Dashboard warning for lighting system

Fix: LED assemblies are sealed units — individual LED modules cannot be replaced. Smart/Mercedes wants $800-1,200 per headlight assembly. Aftermarket options exist but quality is hit-or-miss. Installation is straightforward, 1 hour per side, but the parts cost kills you.

Estimated cost: $900-2,400

Typical onset: 40,000-70,000 mi

Symptoms: Brake pedal feels spongy or requires excessive pressure, Vehicle pulls to one side during braking, One wheel excessively hot after driving, Parking brake won't release or drags

Fix: Calipers corrode internally faster than expected, likely due to small caliper pistons and aggressive pad compounds. Rebuilds rarely last — replacement recommended. Rear calipers integrate parking brake mechanism, more expensive. Front calipers 1.5 hours each, rears 2 hours each. Do both sides simultaneously.

Estimated cost: $400-800

Typical onset: 50,000-90,000 mi

Symptoms: Transmission fluid spots under vehicle, rear-center location, Transmission overheating warnings in hot weather or traffic, Low transmission fluid warning on dashboard, Burnt smell from rear of vehicle

Fix: The auxiliary transmission cooler develops leaks at line connections or the core cracks. Cooler itself is inexpensive but access requires removing rear bumper cover and undertray. Plan 2-3 hours labor, plus fluid refill and system bleed. Must use proper dual-clutch fluid spec (not cheap).

Estimated cost: $500-850

Typical onset: 50,000-100,000 mi

Symptoms: Check engine light with codes P0299 (underboost) or P0234 (overboost), Loss of power, especially on highway on-ramps, Turbo whistle or fluttering sounds under acceleration, Limp mode activation in severe cases

Fix: Electronic wastegate actuator sticks or fails, also vacuum line leaks common. Diagnosis requires boost pressure testing. Wastegate actuator replacement is 2-3 hours due to rear-engine access. Sometimes just cleaning carbon buildup from wastegate arm resolves it. Turbo replacement rare but runs $1,800-2,500 if needed.

Estimated cost: $350-800