Mercedes-Benz W204 ABS Pump A2045454632 - Used Original Parts

Quick Answer

A W204 C-Class with ABS and ESP warning lights, a brake pedal that feels wrong, or a pump motor that runs with no signs of life usually has a failed hydraulic unit, and this is the part to replace once the wheel speed sensors and wiring have been ruled out. A tested used original unit suits Malaysia well. A Genuine unit built to Mercedes-Benz specification is far more reliable than an unknown aftermarket rebuild, and it avoids the cost and lead time of a new dealer part on a car that is often more than ten years old. The unit must match the car's variant and be bled and coded correctly after fitting.

Diagnosis and Common Symptoms

The W204 ABS/ESP hydraulic unit combines a valve block, a return pump motor and an attached control module. In Malaysian conditions, heat cycling, humidity and old brake fluid are the usual causes of failure. Brake fluid absorbs moisture over time, which corrodes valve bores and stresses the pump motor. Heavy stop-and-go traffic and flood exposure add to the wear.

Typical symptoms:

• ABS, ESP and BAS warning lights on together, sometimes with a red brake warning
• "ESP inoperative" or similar message in the instrument cluster
• Pump motor running continuously, or never running during the self-test at start-up
• Hard, long or inconsistent brake pedal, especially under ABS intervention
• ABS cutting in at low speed on dry roads, or not working at all
• Stability control and traction control disabled, with the car feeling unsafe in wet weather
• Intermittent faults that clear after a restart, then return when the car is hot

Typical diagnostic findings:

• Control unit internal fault, or loss of communication on the CAN bus
• Return pump motor fault or implausible motor current
• Valve (solenoid) fault, or pressure sensor plausibility errors
• Wheel speed signal faults that do not clear after the sensor and wiring are replaced

Before condemning the pump, check the battery voltage, ground points, fuses, wheel speed sensors, brake light switch and the connector pins for corrosion. If the faults persist with a healthy supply and good signals, the hydraulic unit is the likely cause. Read the fault memory with a Mercedes-capable scan tool (Xentry or equivalent) so the diagnosis is confirmed and not guessed.

Introduction

This is a Genuine Used ABS pump removed from a Mercedes-Benz W204 C-Class. Every unit is tested before listing, so you receive a working part and not a gamble. A Genuine used original unit keeps the factory valve block, motor and control module design that the W204 braking system was calibrated for. It is a practical alternative to an expensive new unit and a safer one than an untested rebuild.

Product Details

• Brand: Mercedes-Benz

• Model Compatibility: W204 C-Class (confirm fitment by part number A2045454632 and your VIN before ordering)

• Part Name: ABS Pump (ABS/ESP Hydraulic Unit)

• Condition: Genuine Used (Tested Working)

• Notes: Match the full part number, as W204 variants differ by engine, ESP specification and drivetrain. After installation, the brake system must be bled properly, ideally with the scan tool pump activation routine, to remove air from the valve block. Depending on the car, the control unit may need variant coding or adaptation with Xentry. Calibrate the steering angle sensor and clear stored faults afterwards. Replace the brake fluid at the same time, since contaminated fluid shortens the life of any hydraulic unit.