Replace Your Vehicle’s Original RD4 Head Unit With A Direct-Fit Blaupunkt RD4 CD Radio (OE-Fit For Citroën/Peugeot). This unit Is A Robust Option For Workshops And Experienced DIYers Looking For An OEM-Style Replacement: It Provides Reliable Radio Reception And CD Playback In Vehicles Where The RD4 Standard Was Factory-Fitted. Ideal For Mechanics Searching By Part Number (9664769677, 657932, 6579PC, N1-02), The Unit Integrates With Original Wiring Harnesses And Preserves Factory Aesthetics When Properly Installed And Coded.

Technical Information

Manufacturer: Blaupunkt / Stellantis (Original Equipment)

Model: RD4 N1-02 (CD)

Product Codes: 9664769677

Other Numbers: 657932, 6579PC, N1-02

Compatible Models

Citroën Berlingo (B9), Citroën C2, Citroën C3, Citroën C3 Picasso, Citroën C3 Pluriel, Citroën C4, Citroën C8, Peugeot 207, Peugeot 307 II, Peugeot 807, Peugeot Partner Tepee.

Function And Typical Faults

The RD4 Head Unit Provides AM/FM Radio Reception And CD Playback With Integration Into The Vehicle’s Electrical System. Common Failure Modes Include Faulty CD Mechanism (Mechanical Wear Or Jamming), Display Or Button Malfunctions Due To Age, Power Loss From Blown Fuses Or Corroded Connectors, And Software/Immobiliser Locking That Requires Diagnostic Pairing To Restore Full Functionality. Electronic Components Such As Electrolytic Capacitors May Degrade Over Time, Causing Intermittent Power Or Audio Issues.

How Often Units Fail And Why

Failures Are Most Likely In Vehicles Older Than A Decade, Especially Where Units Have Been Exposed To High Humidity, Temperature Cycles, Or Frequent Use Of The CD Mechanism. Mechanical Wear On Moving Parts (Tray/Spindle/Laser) And Connector Corrosion Are The Most Frequent Causes. Electrical Faults Caused By Poor Grounding Or Aftermarket Modifications Can Also Lead To Unit Malfunction.

How To Replace

1. Disconnect The Negative Terminal Of The Battery Before Starting Work To Avoid Short Circuits Or Data Loss.
2. Remove Surrounding Trim Panels Carefully Using Plastic Trim Tools To Avoid Damage.
3. Unscrew The Factory Head Unit Fasteners And Slide The Unit Out Gently.
4. Disconnect The Antenna Cable, Wiring Harnesses, And Any Additional Connectors (Steering Wheel Control, Microphone If Present). Inspect Connectors For Corrosion Or Bent Pins.
5. Install The Replacement Unit By Reversing The Procedure: Connect Harnesses, Secure The Unit, Refit Trim.

Pairing And Coding

This Radio Requires Diagnostic Pairing/Coding To The Vehicle. Pairing Is Typically Performed With A Compatible PSA Diagnostic Tool (DiagBox/Lexia/PP2000) Or Equivalent Workshop Equipment To Unlock Features And Ensure Proper Communication With The Vehicle’s Bus Systems. If The Unit Is Not Coded, It May Remain Locked Or Exhibit Limited Functionality.

Installation Recommendations

Installations Should Be Performed By Experienced Technicians Or Skilled DIYers Familiar With PSA Electrical Systems. Check And Replace Any Blown Fuses Before Assuming The Radio Is Faulty. Ensure All Earth Connections Are Clean And Tight. If Retaining Steering Wheel Controls Or Other Vehicle Integrations, Verify That Adapters Or Interface Modules Are Compatible With The RD4 Standard. After Installation, Perform Diagnostic Pairing And Verify Radio, Antenna, And Control Functions.

Reason Why The Part Most Commonly Fails

The Most Common Reason For Failure Is Mechanical Wear Of The CD Mechanism And Connector Corrosion Leading To Power Or Signal Loss. Environmental Factors (Moisture, Heat), Age-Related Component Degradation, And Electrical Issues Caused By Poor Grounds Or Aftermarket Modifications Are Frequent Contributors.

Original Blaupunkt RD4 CD head unit designed for many PSA vehicles. This unit restores factory audio functions with a direct OEM fit, offering reliable CD playback and radio reception while maintaining the vehicle’s original dashboard appearance. Ideal for professional workshops and experienced DIYers who need a proven replacement part identified by common product numbers (9659138977 / 657932 / 6579PC).

Compatibility

• Citroën Berlingo (B9)
• Citroën C2
• Citroën C3
• Citroën C3 Picasso
• Citroën C3 Pluriel
• Citroën C4 (selected versions)
• Citroën C8 (selected versions)
• Peugeot 207
• Peugeot 307 (including Mk2)
• Peugeot 807
• Peugeot Partner Tepee

Technical Information

• Manufacturer: Blaupunkt
• Model: RD4 CD
• Product Codes: 9659138977, 657932, 6579PC
• Additional Numbers: PSA/Stellantis references commonly listed under the above codes

Installation Recommendations

Before starting any work, always disconnect the vehicle battery to prevent damage to the unit and vehicle electronics. Remove surrounding trim panels and the securing bolts to extract the original radio. Carefully unplug the antenna lead and electrical connectors; inspect connectors and wiring for corrosion or damage. Fit the replacement unit by reversing removal steps, ensuring all plugs are fully seated and the antenna is secure. Verify the correct fuse rating before reconnecting the battery.

Programming and Coding

This radio requires coding to the vehicle via diagnostic equipment to function correctly. Use PSA diagnostic tools such as DiagBox / PP2000 (or equivalent compatible diagnostic interfaces) to register and initialise the unit. Without proper coding the radio may have limited functionality or may not be recognised by the vehicle CAN network. If you are not experienced with PSA coding procedures, commissioning the programming to a technician with appropriate diagnostic equipment is recommended.

Most Common Causes Of Failure

• Worn CD mechanism or laser pickup failure after many years of use.
• Water ingress or moisture causing corrosion to internal electronics or connectors.
• Electrical issues such as poor ground, blown fuses, or voltage spikes damaging power circuits.
• Corroded or loose connectors leading to intermittent audio or power loss.
• Software/compatibility issues when installing an uncoded or incorrectly coded unit.

How To Replace

1. Disconnect the negative battery terminal and wait a few minutes.
2. Carefully remove trim surrounding the radio using appropriate trim tools to avoid damage.
3. Unscrew the head unit mounting bolts and slide the unit out of the dash.
4. Unplug the antenna cable and electrical connectors, noting connector positions.
5. Fit the replacement radio, connect all leads and the antenna, then secure with mounting bolts.
6. Reconnect the battery and use diagnostic equipment to code/register the radio to the vehicle.
7. Perform a full function test: radio, CD playback, controls, and any integration with steering wheel or vehicle systems.

Why This Unit

The Blaupunkt RD4 CD is a factory-style replacement that preserves original vehicle aesthetics and basic audio functions. Using the correct product codes (9659138977 / 657932 / 6579PC) ensures you receive a unit compatible with PSA dashboards. Suitable for mechanics and competent DIY installers who can perform the physical swap and arrange the necessary diagnostic coding.

This Blaupunkt RD4 unit is an OEM-style CD radio commonly fitted to a range of Citroën and Peugeot models. It appears under several part numbers used by Stellantis and aftermarket suppliers, making it easy to find by product code (for example 9660646877). Ideal for professional workshops and DIY mechanics who replace or repair factory head units, this radio restores factory audio functions and original dashboard appearance.

Technical Information

• Manufacturer: Blaupunkt
• Model: RD4
• Product Codes: 9660646877
• Other Numbers: 9659138977, 9647521077, 657932, 6579PC

Compatibility

Commonly fitted to: Citroën C2, Citroën C3 (first generation), Citroën C4, Citroën C8, Peugeot 207, Peugeot 307 II, Peugeot 807. Always cross-check the unit faceplate and connector layout against the vehicle before installation.

Function and Features

The RD4 unit provides FM/AM radio reception and CD playback with the standard RD4 control interface used across many PSA vehicles. When correctly programmed, it integrates with the vehicle’s audio system and maintains original dashboard ergonomics.

Installation

Basic replacement steps:

• Disconnect the vehicle battery before starting work to avoid short circuits and protect electronic modules.
• Remove surrounding trim panels carefully to access the head unit retaining screws.
• Unscrew the unit, pull it out gently and disconnect the antenna and wiring harnesses.
• Fit the replacement unit, reconnect harnesses and antenna, secure with screws and reinstall trim.
• Program the radio to the vehicle using PSA diagnostic tools (DiagBox/Lexia/PP2000) to restore full functionality and anti-theft alignment.

Installation Recommendations

Always follow manufacturer procedures and safety precautions. If you are not experienced with vehicle electronics, programming or dashboard removal, entrust the final coding and setup to a qualified technician with PSA diagnostic equipment. Before disconnecting any connectors, ensure you have a clear workspace and the correct tools to avoid damaging plastic clips or connectors.

Most Common Failure Reasons

• Worn or jammed CD mechanism caused by age and frequent use.
• Electrical surges or poor battery connection causing internal electronic faults.
• Corroded or loose connector pins and antenna connections leading to intermittent operation.
• Moisture ingress from leaks or high-humidity environments damaging internal components.
• Firmware or configuration issues that require reprogramming with diagnostic tools.

Expected Service Life

Service life depends on usage and vehicle environment. Many RD4 units remain operational for many years, but mechanical parts such as the CD mechanism and age-related electronic degradation make failures more likely after long service (typically many years of use).

Notes

This unit is supplied as indicated by the part numbers above. The radio requires vehicle-specific programming to enable full functionality and anti-theft alignment.

Product Overview

Reliable Blaupunkt RD4 B5 N1 CD head unit designed for a range of PSA cars. This original-style radio offers AM/FM reception with RDS and an integrated single-disc CD player, matching the factory look and controls of compatible Citroën and Peugeot models. Ideal for mechanics and DIY enthusiasts looking to replace a faulty factory radio while keeping vehicle functions such as steering wheel controls and dash integration intact.

Technical Information

• Manufacturer: Blaupunkt
• Model: RD4 B5 N1 (CD Radio)
• Product Codes: 9647521077, 9659138977
• Other Numbers: 657932, 6579PC
• Compatible Models: Citroën C2, Citroën C3 (including C3 Pluriel), Citroën C4; Peugeot 207, Peugeot 307 II, Peugeot 807, Peugeot C8

Installation Recommendations

• Always disconnect the vehicle battery before starting removal or installation to avoid short circuits and damage to vehicle electronics.
• Use the correct radio removal keys or tools to avoid breaking trim and retain all fastening clips and screws for reassembly.
• Mark or photograph connector positions before unplugging to ensure correct reconnection of antenna, power, speaker and control connectors.
• After mechanical installation, perform the required diagnostic coding to register the radio to the vehicle using PSA diagnostic tools (e.g., DiagBox/Lexia/PP2000) so that all integrated functions operate correctly.
• Verify antenna connection and radio reception, operation of the CD mechanism, and steering wheel control functions after coding.

How The Part Is Replaced

1. Remove the trim surrounding the radio using appropriate trim tools.
2. Extract the old radio using radio removal keys and unscrew mounting brackets if present.
3. Disconnect the antenna and all electrical connectors from the rear of the unit.
4. Install the replacement unit, reconnect all connectors and antenna, and secure mounting brackets.
5. Reconnect the battery and perform diagnostic coding/registration of the radio to the vehicle.
6. Test all functions—radio reception, CD play, RDS, steering wheel controls and sound output—before reassembling the trim.

Most Common Causes Of Failure

Failure of RD4 units is usually caused by age and mechanical wear of the CD mechanism (laser failure or tray jams), accumulation of dust or debris, moisture ingress leading to corrosion on connectors or internal circuit boards, and voltage surges affecting internal electronics. Faulty or loose antenna/plug connections can also cause poor reception or intermittent operation. Regular use over many years increases the likelihood of mechanical faults in the CD drive.

Search And Identification

Customers commonly search by product code. Use reference numbers 9647521077, 9659138977, 657932 or 6579PC when looking up compatibility and listings for this Blaupunkt RD4 unit.