Description
Hydraulic control block for ABS and ESP brake systems for CITROËN C4 and Peugeot 307. Supplied with a section of the wiring harness.
This used ABS/ESP hydraulic unit with attached wiring is a direct-fit replacement for many Citroën C4 and Peugeot 307 vehicles. Designed to restore anti-lock braking and electronic stability functions, the module contains the hydraulic modulator, pump motor and solenoid valves required to control brake pressure independently at each wheel. The unit is commonly searched for by part numbers listed below, making it easy to find when repairing braking systems in workshop or DIY environments.
Technical Information
- Manufacturer: Stellantis / Citroën / Peugeot
- Model: Citroën C4, Peugeot 307
- Product Codes: 9657352780, 4541J1
- Additional Numbers: 0265800395, 0265231486, 9649988280
Function and Application
The hydraulic control block (ABS pump/module) modulates brake pressure during anti-lock braking events and works with the ESP system to maintain vehicle stability. It receives wheel speed and yaw sensor inputs, activates solenoid valves and the pump to reduce or increase pressure on individual brake circuits, and communicates with the vehicle ECU to coordinate ABS and traction control interventions.
Fitment and Compatibility
Intended for Citroën C4 and Peugeot 307 models. The unit is frequently identified and ordered by the product codes listed above. Always match the part numbers when searching for a replacement to ensure correct fitment and connector layout.
Replacement Procedure
- Prepare Vehicle: Park on level ground, engage parking brake and support vehicle securely if wheels need removal.
- Electrical Safety: Always disconnect the battery before beginning removal to avoid damage to the unit or vehicle electronics.
- Brake Fluid: Drain or be prepared for brake fluid loss. Use appropriate containers and observe environmental rules for disposal.
- Disconnect: Remove electrical connector(s) and the wiring section supplied. Label brake lines if necessary and loosen banjo bolts or unions.
- Remove Unit: Unbolt the ABS hydraulic unit from the mounting bracket and remove from vehicle.
- Install New Unit: Fit the replacement unit, secure bolts to manufacturer torque where available, reconnect brake lines with new crush washers if required and reconnect electrical connectors.
- Bleeding and Initialization: Thoroughly bleed the brake system to remove air. After mechanical installation, perform ABS/ESP initialization and any required coding or sensor calibration using a suitable diagnostic tool (see Installation Recommendations below).
Installation Recommendations
- Always Disconnect Battery Before Removal: To prevent damage to the unit and vehicle electronics, disconnect the battery prior to work.
- Use Proper Tools and Protective Equipment: Wear gloves and eye protection when working with brake fluid.
- Brake Fluid: Use the correct specification brake fluid (typically DOT4 for these models) and replace contaminated fluid during service.
- Leak and Corrosion Check: Inspect brake lines, unions and electrical connectors for corrosion or damage and replace defective parts.
- Diagnostic Equipment: After replacement, use a PSA-compatible diagnostic tool (DiagBox/Lexia/PP2000) to confirm system status, clear fault codes and perform any required initialization or adaptations.
Why This Part Commonly Fails
Common failure causes include corrosion and moisture ingress that affect hydraulic channels or electrical connections, pump motor wear, contamination from old or dirty brake fluid, mechanical damage from impacts or accidents, and wiring harness deterioration. Symptoms of a failing unit include ABS warning lights, intermittent ABS operation, longer braking distances under heavy braking, or unusual pump/hum noises during ABS cycles.
Because the hydraulic unit operates in a harsh environment and contains moving parts and electrical components, failures are typically related to age, exposure to moisture and contamination. Regular brake fluid changes and corrosion inspection help prolong service life.
Notes for Buyers
Supplied With: Section Of Wiring Harness. The unit is commonly identified by the product numbers shown in the Technical Information section. Suitable for workshop professionals and competent DIYers who have experience with brake systems and diagnostic tools.
Purchase this hydraulic ABS/ESP control block to restore proper anti-lock and stability control functions on compatible Citroën C4 and Peugeot 307 vehicles. Ensure you follow safety procedures and use appropriate diagnostic equipment for final commissioning.
