Dacia Bigster Hybrid 155 Mk1

The Bigster Hybrid 155 uses Renault's E-Tech clutchless multimode automatic gearbox, a design with roots in Formula 1 technology. It replaces a traditional clutch with a secondary electric motor that synchronizes gear speeds. While the system has been refined compared to earlier 1.6 E-Tech versions, owners report noticeable hesitation during low-speed manoeuvres, delayed response when requesting sudden acceleration (up to 1-2 seconds in some reported cases), and jerky transitions between electric and petrol modes, especially on inclines. German forum members describe the combustion engine sometimes staying on at traffic lights longer than expected while the battery management system performs charge cycles. Renault has released multiple software calibration updates that improve shift smoothness. A dealer software update is free under warranty or costs €100-200 at an independent specialist if outside warranty. The fundamentally improved 1.8 HR18 version is reported to be smoother than the 1.6 in the Duster, though the underlying gearbox design is the same.

The Renault E-Tech hybrid gearbox has a well-documented history of an internal O-ring seal defect that allows gearbox oil to leak onto the electric motor. This triggered a recall affecting approximately 155,825 vehicles built between April 2019 and September 2022 across the Clio, Captur, Arkana, Megane, and Jogger. The Bigster uses an evolved version of this gearbox with the improved X-ring seal design from the factory, making this issue substantially less likely on new production. However, the fundamental gearbox architecture is shared. If the seal were to fail, oil contamination of the electric motor can cause overheating warnings, immobilization, and eventual motor failure. Early detection (seal replacement only) costs €800-1,200, while a complete gearbox replacement if the motor is damaged runs €3,000-3,500. Given that the Bigster is built from 2025 onward with the corrected seal, the probability is low, but the consequence is significant enough to warrant monitoring.

As a model launched in early 2025, the Bigster Hybrid 155 shows typical first-year software immaturity. German and French forum owners report intermittent issues including the MyDacia app failing to connect or register, the infotainment system requesting unexpected security codes, Bluetooth connectivity drops requiring manual re-pairing, blind spot sensors activating falsely in heavy rain, adaptive cruise control producing jerky acceleration, and automatic headlights engaging without cause. One French owner documented multiple dealer visits without resolution, waiting three months for a technical response from Dacia. Dacia has scheduled a comprehensive software update package and continues to push over-the-air fixes. Most of these issues cost nothing to fix under the 3-year warranty, but diagnosis and manual updates at a dealer can cost €100-300 if outside warranty. These problems are expected to diminish as software matures through 2026.

This is a common characteristic across Renault/Dacia E-Tech hybrid vehicles rather than a defect specific to the Bigster. The numerous electronic modules (hybrid management, infotainment, security system) draw standby power that can deplete the 12V auxiliary battery within 7-14 days of inactivity. When the 12V battery voltage drops too low, the hybrid system cannot initialize, which can trigger cascading warning lights (braking fault, steering fault, hybrid system error) that are caused by low voltage rather than actual component failure. A jump start or battery charge typically resolves all warnings. The 12V battery has a typical lifespan of 3-5 years. Replacement costs €150-250 for the battery plus €50 for fitting. A quality trickle charger (€40-80) is recommended for owners who do not drive the car daily.

The HR18 engine uses gasoline direct injection with a mandatory gasoline particulate filter (GPF) to meet Euro 7 standards. Like all GPF-equipped petrol engines, passive regeneration occurs at exhaust temperatures above 600 degrees Celsius, typically achieved during sustained highway driving. If the car is used exclusively for short urban trips, the filter can become clogged, triggering warning lights and potentially requiring forced regeneration at a dealer (€300-500) or, in extreme cases, filter replacement (€800-1,200). This risk is partially mitigated by the hybrid system, which reduces combustion engine running time in urban driving, meaning less soot is generated in the first place. Owners who regularly mix in highway trips of 20+ minutes should have no issues.