Description
Overview
This ABS/ESP control unit is a combined electronic control module and hydraulic pump assembly typically used on PSA vehicles. Supplied by Bosch as an OE component for Citroën, it handles anti-lock braking (ABS) and electronic stability program (ESP) functions to maintain vehicle stability and prevent wheel lock under braking.
Key Features
- Complete ABS pump and ECU assembly (electro-hydraulic unit).
- Restores ABS and ESP functions when the original unit is faulty or electrically damaged.
- Matches Bosch original part numbering for direct replacement: 0265950072 and reference 4541C8.
Function And Symptoms Of Failure
The unit monitors wheel speed sensors and modulates hydraulic brake pressure to prevent wheel lock and to assist vehicle stability control. Common symptoms indicating a faulty unit include:
- ABS or ESP warning light illuminated on the dashboard.
- Loss of ABS/ESP functionality, longer braking distances, or wheel lock under heavy braking.
- Unusual pump noises from the hydraulic assembly or intermittent braking faults.
- Fault codes related to hydraulic pump circuit, valve faults, or internal ECU communication errors.
Typical Causes Of Failure
- Electrical faults such as damaged wiring, corroded connectors, or failed internal electronics.
- Hydraulic contamination or corrosion affecting valves and the pump.
- Moisture ingress in the module area leading to connector corrosion or short circuits.
- Age-related wear of internal components after many years and mileage.
Replacement And Installation Notes
Replacing the ABS/ESP unit requires mechanical and diagnostic experience. Typical replacement steps include:
- Disconnect the vehicle battery before starting work to avoid electrical damage.
- Read and record all ABS/ESP fault codes with a compatible diagnostic tool prior to removal.
- Remove any protective covers and disconnect electrical connectors and hydraulic brake lines from the unit.
- Install the replacement unit, carefully reconnect hydraulic lines using new sealing washers where applicable, and torque to manufacturer specifications.
- Bleed the brake system thoroughly after installation to remove air from the hydraulic circuit.
- Perform module initialization and, where required, coding or VIN adaptation with a suitable diagnostic scanner to ensure the ECU is recognized by the vehicle systems.
Note: Some vehicles require professional diagnostic tools to code the new module and complete adaptation routines. If you are unsure, ask a qualified technician to perform the final coding and vehicle checks.
Compatibility And Fitment
Primary fitment: Citroën Xsara Picasso. This unit is an OE Bosch assembly used across certain PSA models; always verify fitment by comparing the exact product codes (0265950072 / 4541C8) with your vehicle’s existing part. If in doubt, provide your VIN to confirm compatibility.
Technical Information
- Manufacturer: Bosch (OE supplier for PSA)
- Model: Citroën Xsara Picasso
- Product Codes: 0265950072
- Other Numbers: 4541C8
Recommendation
For safety-critical components like the ABS/ESP unit, installation by an experienced mechanic is recommended. Verify part numbers before purchase and ensure post-installation diagnostics, bleeding, and coding are completed to restore full braking and stability system performance.
