Part description

This used part is a Bosch ABS ESP pump, i.e. a hydraulic brake control unit with ABS/ESP control function. It is an important part of the braking system, which is involved in regulating the braking effect and stabilization functions of the car.

The part is intended for Citroën C4 PICASSO and is also searched for by production numbers. For mechanics and home repairers, it is an advantage to be able to compare the original piece according to the label, connectors and Bosch marking directly on the unit.

The used original car part is particularly suitable as a replacement for a non-functional, damaged or electronically defective ABS/ESP module when it is necessary to maintain the appropriate design for the given car.

Technical information

• Manufacturer: Bosch
• Model: Citroën C4 PICASSO
• Other numbers: 9665106680, 0265950962, 4541EY, 4541EZ, 4541QE

Product codes

• Product codes: 9665106680, 0265950962, 4541EY, 4541EZ, 4541QE
• Models: Citroën C4 PICASSO

Installation recommendations

This part is an ABS/ESP module with hydraulic and electrical parts. The exact replacement procedure may vary depending on the specific model of the car, so below is a general and typical procedure for this type of part.

1) Before assembly

• Check that all the numbers on the original and new part match.
• Compare the shape of the unit, the mounting, the placement of the outlets and electrical connectors.
• Inspect the used part for mechanical damage, cracks or contamination at the connection points.
• Make sure that the connection surfaces and connectors are not oxidized or deformed.

2) Necessary tools and materials

• Basic set of hand tools
• Suitable tools for removing fasteners and connectors
• Cleaning agent for technical components
• Clean rags without fibers
• Protective gloves
• Diagnostic equipment suitable for subsequent system control

3) Step-by-step assembly procedure

1. Park the vehicle in a safe place and secure it against movement.
2. Disconnect the battery according to normal service practice to avoid damaging the electronics.
3. Access the ABS/ESP unit compartment and carefully disconnect the electrical connector(s).
4. Mark the individual connections to avoid confusion during assembly.
5. Disassemble the original unit including the mount, being careful not to damage the surrounding parts.
6. Compare the removed part with the new piece once again just before installation.
7. Mount the used unit in its original location and seat it without tension.
8. Connect all electrical connectors carefully and without using excessive force.
9. Check the correct fit and strength of all connections and fasteners.
10. Connect the battery and perform a basic electrical communication check of the system.
11. If the design requires it, perform a diagnostic check and follow-up service operations common to the ABS/ESP system.
12. When finished, verify that there are no errors indicating incorrect mounting or a non-communicating drive.
• 4) Post-assembly checks and test drive/function verification
  • Check that the part is firmly seated and that the connectors are properly engaged.
  • Verify that after switching on the ignition, the system behaves normally and does not report an obvious fault.
  • Run a diagnostic check if available.
  • During the test drive, observe the behavior of the brake system and any warning lights.
  • After driving, recheck the attachment and the overall condition of the area around the mounted part.

  5) The most common assembly mistakes + how to avoid them

  • Exchanging a part based on an incomplete designation – always compare all numbers and designs.
  • Damage to the connector during disassembly – release the connectors carefully and without prying with an inappropriate tool.
  • Assembly of the dirty part – clean the connection and contact surfaces before installation.
  • Insufficient seating of the unit – after tightening, check that the part is not tight and nothing is loose.
  • Omission of the diagnostic check – after assembly, it is advisable to verify the system function and the communication of the unit.

  Reasons why the part is damaged

  • normal wear and tear of electronic and mechanical parts during operation,
  • moisture, corrosion or oxidation in the area of connectors and contacts,
  • vibration and long-term thermal stress,
  • damage due to unprofessional disassembly or assembly,
  • electrical defects in the vehicle installation that may affect the operation of the ABS/ESP unit.
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