Reliable replacement BSM B2 unit from Delphi designed for Citroën and Peugeot vehicles. Ideal for professional workshops and experienced DIY mechanics searching by part number (9644038780, 6500Y1). The module controls and coordinates engine-related electrical circuits; replacing a faulty BSM restores stable engine management, starting and electrical feeding of related subsystems. Supplied as a used unit with functional warranty, it represents a cost-effective alternative to a new original part while retaining OEM compatibility for the listed models and part numbers.

Technical Information

• Manufacturer: Delphi
• Model: BSM B2
• Product Codes: 9644038780
• Additional Numbers: 6500Y1, 6500Y11

Compatible Models

Commonly fitted to various Citroën and Peugeot models. Frequent applications include Peugeot 206 and Peugeot 307 where the above product codes are used. Search by part number (9644038780 / 6500Y1) for quick compatibility checks.

Installation Recommendations

• Always disconnect the battery before starting work and follow the vehicle manufacturer’s disassembly procedure to avoid damage to the unit or vehicle electronics.
• Access the unit by removing the protective covers or battery tray as required on the specific model.
• Carefully unplug electrical connectors using appropriate tools; avoid bending or pulling on wiring.
• Mount the replacement unit securely and reattach connectors so that locking tabs fully engage.
• After installation, perform basic checks: battery connection, ignition, and that related systems (starter, sensors, dashboard indicators) respond correctly. If further diagnostics or coding are required, use suitable PSA diagnostic tools or consult a qualified technician.

Most Common Failure Reasons

BSM units typically fail due to environmental and electrical stresses rather than normal wear. Typical causes include water ingress or condensation leading to corrosion, damaged or cracked connector housings, short circuits or voltage spikes, and physical impact to mounting points. In many cases symptoms appear as intermittent starting problems, dashboard warning lights, loss of engine management functions or blown fuses related to the engine electrical circuits.

Practical Notes For Mechanics

Because many customers search by OE number, listing the exact part codes (9644038780, 6500Y1) significantly increases findability. The unit is plug-in replaceable on vehicles where the connector and mounting match; however, confirm mechanical fitment and connector type before final installation. Minor damage to external brackets does not affect electrical function but secure mounting is recommended to avoid vibration-related issues.