Overview

BSI04EV K04-00 body control module (BSI) by Johnson Controls for Citroën and Peugeot vehicles is a commonly replaced comfort and central electronics unit. This unit controls lighting, central locking, wipers, interior electronics and communicates with the instrument cluster and immobiliser. It is often searched by part numbers such as 9664059080, 1663370780, 657064 or K04-00 — include these numbers when searching to locate the correct unit quickly. This description is written for professional technicians and experienced DIY mechanics who service Citroën/Peugeot vehicles.

Technical Information

• Manufacturer: Johnson Controls
• Model: Citroën C4 Grand Picasso (From 2008)
• Product Codes: BSI04EV, K04-00, 9664059080, 02 1663370780, 657064, 1663370780
• Other Numbers: BOOT 28120836-4, HARD 28119248-3B

Fitment And Compatibility

This BSI unit is fitted to Citroën C4 Grand Picasso models from around 2008 and to vehicles within the PSA group that use the BSI04EV K04-00 hardware. Compatibility must be confirmed by matching the unit’s part numbers listed above. Searching by the OEM numbers (9664059080, 1663370780, 657064) will help you find matching units and cross-references.

Function And Symptoms

The BSI (Body System Interface) is the central comfort electronics module. It manages functions such as central locking, interior and exterior lighting logic, wiper control, convenience features, and data exchange with the dashboard and immobiliser. Faulty BSI units commonly produce symptoms like intermittent or permanent loss of central locking, non-functional interior lights, erratic wiper behaviour, dashboard warning lights, immobiliser or starting problems, and multiple electrical anomalies that are otherwise hard to trace.

Replacement Procedure (Summary)

Replacement of the BSI typically involves these steps: disconnect the negative battery terminal before any work; remove relevant trim or glovebox to access the unit; unscrew mounting fasteners and carefully unplug multi-pin connectors; install the replacement unit and secure connectors; reconnect the battery and perform necessary coding/initialisation (see coding section). Handle the unit with ESD precautions and avoid connector pin damage. If the vehicle has immobiliser integration, additional steps for transponder/key adaptation may be required.

Installation And Coding – Important

• The Unit Is Used And Is “Paired” With The Original Vehicle (VIN/PIN/Keys).
• Options For Commissioning:
1. Cloning Data From The Old Unit (EEPROM/Flash) – After Cloning The Unit Is Plug And Play.
2. Virginisation And Subsequent Initialization/Telecoding Via DiagBox (Or Online) + Key Adaptation.
• Recommended To Be Performed By A Technician With PSA Service Equipment (DiagBox/Lexia/PP2000).
• Always Disconnect The Battery Before Removal/Installation And Follow Manufacturer Procedures To Avoid Damaging The Unit.

Installation Recommendations

Always isolate the battery negative before starting. Inspect and clean connector pins and earth points before fitting the new unit. Protect the module from static discharge and moisture. Tighten mounting bolts to original torque and ensure no wiring is pinched behind trim. After mechanical installation, perform the appropriate coding or cloning procedure using DiagBox/Lexia/PP2000 to restore full functionality.

Why This Part Fails Most Often

Common failure causes include water ingress and corrosion (especially in vehicles with compromised seals), thermal stress and solder joint fatigue, voltage spikes from poor battery/alternator regulation, and connector corrosion. Electrically induced damage from incorrect jump-starting or short circuits can also destroy internal components. Regular failure signs are intermittent electronics, sporadic central locking, or complete loss of certain comfort functions.

Notes For Mechanics And DIYers

When diagnosing BSI-related faults, always check fuses, grounds and connector integrity before replacing the module. If uncertain about coding or immobiliser adaptation, seek assistance from a technician equipped with PSA diagnostic tools. Use the listed part numbers to ensure you obtain the correct BSI04EV K04-00 version for the vehicle.

Overview

The BSI (Body Systems Interface) BSI04EV K04-00 is a comfort / central body control unit used in Citroën and Peugeot vehicles. Manufactured by Johnson Controls and fitted on selected Stellantis models, this module manages a wide range of vehicle convenience and safety functions such as central locking, interior lighting, wiper and washer logic, power windows, alarm and keypad/remote interactions. Technicians and DIYers commonly identify this part by its reference numbers and module code listed below.

What This Unit Does

This BSI acts as the central gateway for many low-voltage vehicle functions: it receives inputs from switches and sensors, processes the information and commands actuators or other modules. Typical responsibilities include managing door locks, interior lighting timing, remote key recognition, comfort delays, alarm triggers and sometimes CAN-bus communication handling between subsystems.

Fitment And Compatibility

Primary fitment: Citroën C4 Grand Picasso (from 2010) and closely related platform derivatives. The module is labeled with multiple manufacturer and product numbers (see Technical Information). Because BSI variants and software/hardware revisions exist, always compare the module codes listed in the Technical Information with the part fitted in the vehicle to confirm compatibility.

Replacement Procedure (General Guidance)

1. Preparation: Park the vehicle on a level surface, engage the handbrake and remove ignition key. Wear an anti-static wrist strap if available. Before any work on the BSI, disconnect the negative battery terminal to avoid short circuits and to protect the electronics.
2. Access: The BSI is typically located behind the glovebox or under the dashboard on the passenger side depending on the model. Remove trim panels or glovebox as required to gain clear access to the unit.
3. Disconnect: Carefully unplug electrical connectors—press release clips and avoid pulling on wiring. Note connector positions and retaining screws.
4. Swap Unit: Replace the module and re-fit connectors and fasteners. Reconnect the battery only after the module is mechanically secured.
5. Coding and Initialization: Most BSI replacements require cloning or coding to the vehicle (see Installation and Coding – Important). After vehicle-side procedures are completed, verify central locking, lights, windows and alarm functions before reassembling interior panels.

Installation And Coding – Important

• The Unit Is Used And Is “Paired” With The Original Vehicle (VIN/PIN/Keys).
• Options To Put The Unit Into Service:
  1. Cloning Data From The Old Unit (EEPROM/Flash) – After Cloning The Unit Is Plug And Play.
  2. Virginization And Subsequent Initialization/Telecoding Via DiagBox (Or Online) + Key Adaptation.
• Recommended To Be Performed By A Specialist With PSA Service Equipment (DiagBox/Lexia/PP2000).
• Before Removal/Installation Always Disconnect The Battery And Follow The Manufacturer Procedure To Avoid Damaging The Unit.

Why This Part Fails Most Often

Common failure causes include water ingress from leaking seals or sunroof drains, corrosion of connectors, electrical surges (battery disconnects performed incorrectly or jump-starting errors), and internal component wear after many years in service. Intermittent faults often present as erratic central locking, loss of remote functions, blown fuses, or multiple seemingly unrelated convenience features failing at once—typical signs of BSI malfunction or communication errors on the vehicle network.

Recommendations For Installation

Have access to proper diagnostic and coding tools when replacing a BSI. If cloning is chosen, ensure a verified full EEPROM/Flash dump is obtained from the original unit. If virginizing and coding, use DiagBox or an approved PSA solution and follow the exact initialization sequence. Always disconnect the negative battery terminal before work, avoid static discharge, and inspect connector pins for corrosion or damage. After installation, run a full vehicle scan and test all convenience functions before refitting trim panels.

Technical Information

Manufacturer: Johnson Controls / Stellantis Compatibility
Model: BSI04EV K04-00
Product Codes: 9664059080, 1663370780, 657064, K04-00
Additional Numbers: 28119248-3B, 28120836-4

Useful Notes For Mechanics

Search and ordering are commonly performed by the module reference numbers above. When diagnosing, check fuses and wiring integrity first—many faults attributed to the BSI are actually caused by power supply issues or poor ground connections. For coding and key adaptation follow PSA procedures and consider professional service for vehicles with immobilizer and key programming requirements.

This BSI (Body System Interface) module BSI04EV K04-00 originating from a Citroën C4 Picasso is a critical central control unit for comfort and body systems. Supplied as a used automotive electronic part, it is aimed at professional mechanics and competent DIY enthusiasts who prefer an efficient, cost-effective replacement by part number.

Function And Benefits

The BSI controls and coordinates multiple comfort and body electronics including central locking, interior and exterior lighting logic, power windows, alarm/immobiliser interfaces and various switch inputs. Replacing a faulty BSI can immediately restore erratic or lost functionality of these systems and avoid more invasive repairs.

Compatibility And Fitment

Primary fitment: Citroën C4 Picasso. The module is commonly referenced by the part numbers printed below; compatibility should always be confirmed against the vehicle VIN and the exact part number (9664059080 01). Some PSA Citroën & Peugeot models sharing the same BSI family may accept this unit—verify cross-references before installation.

Replacement And Installation Notes

Typical replacement steps (general guidance):

• Disconnect the vehicle battery before starting to avoid short circuits.
• Remove necessary trim panels in the dash or glovebox area to access the BSI housing.
• Unplug all connectors carefully, noting their positions; remove mounting fasteners and extract the old unit.
• Install the replacement BSI, reconnect connectors and reassemble trims.
• Re-connect the battery. In many vehicles, the replacement module will require diagnostic confirmation, coding or immobiliser synchronization using a PSA-compatible diagnostic tool to restore full functionality.

Estimated labour time: typically 0.5–1 hour depending on access and whether coding is required.

Common Failure Causes And Service Life

BSI failures are most often caused by moisture ingress, corrosion on connector pins, voltage spikes, thermal stress or aging electronic components. Symptoms include intermittent or permanent loss of central locking, inconsistent lighting behavior, or failure of powered windows. Regular inspection of connectors and protection against water exposure can prolong service life.

Technical Information

Manufacturer: Johnson Controls
Model: Citroën C4 Picasso
Product Codes: BSI04EV K04-00
Other Numbers: 9664059080 01, 657064, 1663370780, BOOT 28120836-4, HARD 28119248-3

This unit has been made available for immediate installation. Always confirm compatibility by part number and, where required, plan for diagnostic coding or synchronization to the vehicle after fitting.