Description
Product Overview
This ABS/ESP Control Unit (ECU) with integrated hydraulic pump is a direct-fit module for the Citroën Xsara Picasso. Identified by Bosch part number 0265950072 and PSA code 4541C8, the unit controls anti-lock braking (ABS) and electronic stability program (ESP) functions by combining electronic control and the hydraulic block into a single assembly. It is intended for mechanics and experienced DIYers who need a reliable replacement part and clear technical guidance.
Key Features
- Integrated ECU and hydraulic pump assembly providing ABS and ESP regulation.
- Bosch-quality components designed for precise valve and pump control.
- Direct compatibility with vehicles listed under the PSA parts references 0265950072 and 4541C8.
- Restores anti-lock braking performance and vehicle stability interventions when matched to the correct vehicle configuration.
Function And Common Failure Modes
The unit measures wheel speed inputs and modulates brake pressure via electro-hydraulic valves and a high-pressure pump to prevent wheel lock and assist vehicle stability systems. Failures typically arise from electrical faults (connector corrosion or wiring damage), hydraulic contamination, internal pump wear, or long-term exposure to moisture leading to corrosion. Wheel speed sensors or related wiring faults can also trigger ECU faults that mimic a module failure.
Replacement And Installation Notes
- Safety First: Always isolate the battery before starting work to prevent short circuits and unintended ABS activation.
- Brake Fluid Handling: Expect to drain some brake fluid when disconnecting lines; use correct DOT fluid and follow safe disposal procedures.
- Mechanical Steps: Unplug electrical connectors, remove mounting bolts, disconnect brake lines from the hydraulic block, and fit the replacement in reverse order.
- Post-Installation: Complete bleeding of the brake system is essential. Many vehicles require a diagnostic scan tool to clear fault codes and to perform ABS/ESP unit coding, calibration, or pump priming sequences.
- Verification: Always verify the part number against the vehicle VIN and run a full diagnostic check after replacement.
When To Replace
Replace the unit when persistent ABS or ESP warnings appear on the dashboard, when diagnostics indicate internal faults, or when hydraulic leaks or pump noise are present. Because the issue can be electrical, hydraulic, or sensor-related, confirm the root cause with diagnostic equipment before replacing the module.
Technical Information
- Manufacturer: Bosch / PSA (Bosch Electronics and PSA Parts Reference)
- Model: Citroën Xsara Picasso
- Product Codes: 0265950072, 4541C8
- Other Numbers: Verify Vehicle Identification Number (VIN) For Exact Match
This description provides the practical technical context a professional mechanic or knowledgeable DIYer needs to assess suitability and to plan safe replacement. For best results, confirm compatibility using the vehicle VIN and perform electronic reinitialisation with a compatible diagnostic tool after installation.
