Start-stop alternator for Golf 1.5 TFSI

The VAG code 05E903020A identifies a 48 V belt-driven e-motor/alternator used in Volkswagen Group mild-hybrid systems. The component simultaneously functions as an electrical generator and as the internal combustion engine's starter motor.

This component operates on the 48 V mild high-voltage network, with a dedicated lithium-ion battery, the DC/DC converter and the vehicle's energy management control units.

It is belt-driven and mounted at the front of the engine. It is primarily intended for 1.5 TSI petrol engines equipped with mild-hybrid technology.

Technical characteristics

• High-power electromechanical unit.
• 48 V mild-hybrid system.
• Power delivery up to approximately 250 A.
• Dedicated electronic management for controlling generation, energy recuperation and assistance phases to the internal combustion engine.
• Poly-V belt drive.

DIPA can service these components thanks to its experience and expertise.

Functions

• Starts the internal combustion engine quickly and quietly during Start&Stop phases.
• Recovers energy during decelerations and braking to recharge the 48 V mild-hybrid battery.
• Assists the internal combustion engine during acceleration and overtaking.
• Enables coasting strategies and temporary engine shutdown when provided by the vehicle.
• Reduces the load required from the internal combustion engine to produce electrical energy.
• Works with the DC/DC converter to power and stabilize the 12 V onboard network.
• Manages frequent engine restarts in urban driving conditions and in traffic.

Model applications

• Volkswagen Arteon/Golf/Tiguan/Passat/Polo/T-Roc/Touran

Typical faults

• Irregular starting and/or Start&Stop not functioning,
• Error messages related to the mild-hybrid system
• Reduced energy recuperation during coastdown.

Final conclusions

The VAG 05E903020A e-motor/alternator is a fundamental component of the 48 V mild-hybrid system and performs starting, electrical generation, energy recuperation and assistance to the internal combustion engine.

DIPA has a wide range of Automotive spare parts: from original parts to aftermarket items selected among the best manufacturers on the market. It also offers reconditioned components restored to like-new performance, providing savings on replacements and contributing to environmental protection through the circular economy. If the part you need is not available, DIPA can recondition your unit on demand, returning full functionality and safety in a short time.