This Bosch ABS control module with part number 0273004440, including the wiring harness, is specifically designed for Citroën and Peugeot vehicles, notably the Citroën Xsara and Peugeot 306 models. It functions as the electronic control unit for the Anti-lock Braking System (ABS), managing the pump and valves to prevent wheel lockup during braking, ensuring enhanced vehicle stability and safety.

Function and Importance

The ABS control module regulates the hydraulic pump and solenoid valves to modulate brake pressure during emergency braking. This prevents wheel lock, reduces skidding, and maintains steering control. Over time, ABS modules may fail due to electronic faults, wiring issues, or pump wear caused by frequent ABS activation in rough driving conditions.

Installation Notes

Replacement involves disconnecting the old unit, including the wiring harness, and installing the new Bosch module. Proper care should be taken to avoid damage to the connectors and ensure correct electrical connections. After replacement, the system may require diagnostic tool calibration to restore full functionality.

Technical Information

• Manufacturer: Bosch
• Vehicle Models: Citroën Xsara, Peugeot 306
• Product Codes: 0273004440, 9636084480, 454153
• Additional Numbers: 273004440

This unit includes the electronic control module, the hydraulic pump, and comes complete with wiring harness for easy installation. The pump works by regulating brake fluid pressure to maintain traction and control, reducing the risk of skidding in emergency situations.

ABS control modules can fail over time due to electrical malfunctions, wear of the hydraulic pump, or contamination within the system. Symptoms of a failing ABS unit include warning lights on the dashboard, brake pedal pulsations, or reduced braking efficiency during hard stops. Replacing the module restores the proper function of the ABS system, critical for safe driving conditions.

Technical Information

• Manufacturer: Bosch
• Models: Citroën Xsara, Peugeot 306
• Product Codes: 0273004480, 0273004440, 9636084480
• Additional Numbers: 454153

Installation typically requires disconnecting the battery, removing the old ABS unit along with its wiring, and fitting the new module. It is highly recommended that programming or system resetting be done with appropriate diagnostic tools to ensure fault-free operation.

This unit integrates the electronic control module and hydraulic pump, ensuring optimal braking performance during emergency stops by preventing wheel lock-up and maintaining vehicle stability.

It is compatible with popular models such as the Citroën Xsara and Peugeot 306. Installation involves connecting the module to the vehicle’s ABS hydraulic system and the onboard electronics, typically located near the engine bay. Replacement is recommended if ABS warning lights activate, braking performance decreases, or hydraulic pump failures occur.

Failures often result from electrical faults, wear of internal components, or contamination of the hydraulic fluid. Proper maintenance of brake fluid and timely diagnosis can prolong the lifespan of the module.

Technical Information

• Manufacturer: Bosch
• Model: Compatible with Citroën Xsara, Peugeot 306
• Product Codes: 0273004440, 454153, 9636084480
• Additional Numbers: 273004440, 454153, 9636084480

Bosch ABS/ESP ECU and hydraulic pump assembly designed for Citroen Xsara vehicles within the PSA group. This unit integrates the electronic control unit (ECU) with the hydraulic pump/block to manage Anti‑Lock Braking (ABS) and Electronic Stability Program (ESP) functions, maintaining vehicle braking safety and stability control under demanding conditions.

Key Functions

The assembly modulates brake pressure during wheel slip events, operates the high‑pressure pump to restore hydraulic pressure when valves isolate a circuit, and communicates with vehicle stability systems to assist yaw and traction control. It is a critical safety component that directly affects braking performance and vehicle stability.

Common Faults And Causes

Typical symptoms include illuminated ABS or ESP warning lights, reduced ABS function, unusual pump or valve noises, intermittent operation, longer stopping distances, or a soft/spongy brake pedal. Common causes are electrical connector corrosion, internal valve wear, motor failure, moisture ingress, or wiring faults. Faults are often diagnosed by fault codes stored in the ABS/ESP control unit.

Replacement And Installation

Replacement should follow safe workshop practice: disconnect the vehicle battery first, read and record ABS/ESP fault codes, relieve system pressure, and clearly mark brake lines before disconnecting. Unbolt the module from its bracket, transfer any brackets or sensors if required, fit the replacement unit, reconnect brake lines to correct torque, and bleed the brake system thoroughly to remove air. After mechanical installation, clear fault codes and perform ABS/ESP adaptation and coding using an appropriate diagnostic tool. Proper diagnostic work and controlled test driving are recommended to confirm full functionality.

Why Units Fail

Failures commonly result from long‑term exposure to moisture and road salts, corrosion of electrical connectors, internal valve or motor wear, or electronic faults due to voltage spikes. Regular inspections and attention to electrical connections can prolong service life.

Compatibility

Direct fit for Citroen Xsara models and compatible PSA group vehicles using the listed part numbers. Always verify compatibility with the vehicle VIN or existing part number before purchase, as identical housings can sometimes differ by software or connector variant.

Technical Information

• Manufacturer: Bosch
• Model: Citroen Xsara (PSA Group)
• Product Codes: 0265950057; 9641975380; 4541C7
• Other Numbers: 265950057; 4541C7; 9641975380

Suitable for professional mechanics and experienced DIYers. Verify part numbers and prepare for diagnostic coding and complete brake bleeding after installation to ensure safe operation.