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.

Product Description

High-quality OEM Continental RD4N1M CD head unit with MP3 playback designed for many Citroën and Peugeot models. This unit offers reliable radio reception, CD playback and MP3 file support from CD media. It is a direct-fit replacement for vehicles equipped with the original RD4N1M system, making it suitable for workshops and experienced DIY mechanics who need an OE-style audio solution.

Fitment And Compatibility

Common fitment includes Citroën and Peugeot models such as Citroën C2, C3 I, C4, C8 and Peugeot 207, 307 II, 807. The unit is often referenced by OE/product numbers and may be listed under multiple part codes—check the numbers below when searching or ordering.

How It Works And What It Does

The unit functions as an in-dash radio tuner and CD player with MP3 playback capability. It provides audio output to the vehicle speaker system and connects to the vehicle wiring harness and antenna. In many vehicles the head unit must be coded/programmed to the car’s electronics to restore full functionality (see technical note below).

Replacement Procedure (Step-by-step)

1. Before starting, disconnect the vehicle battery to avoid short circuits and protect vehicle electronics.
2. Remove surrounding trim panels carefully using appropriate trim tools to avoid damage.
3. Unscrew and slide the head unit from the dash using the correct removal keys or screws.
4. Unplug the main wiring harness(es), antenna connector and any auxiliary or microphone leads.
5. Install the replacement unit by reversing the removal steps: connect harnesses, secure the unit, re-fit trim and reconnect the battery.
6. Perform the required diagnostic coding/programming so the radio is recognized and fully functional with the vehicle systems.

Installation Recommendations

Always disconnect the battery prior to removal/installation and follow the vehicle manufacturer’s service procedures to avoid damage. Because this radio requires diagnostic coding to the vehicle, coding should be performed with appropriate PSA diagnostic tools. If you are not experienced with PSA programming tools, we recommend installation and coding by a professional workshop equipped for Citroën/Peugeot diagnostics.

Technical Information

Manufacturer: Continental
Model: RD4N1M (CD with MP3)
Product Codes: 9665751777
Additional Numbers: 657992, 657990, 657989, 657937, 657935, 657934, 6579PC

Common Failure Causes

Failures typically result from mechanical wear in the CD mechanism, dust or debris in the loader, moisture ingress or corrosion on connector pins, intermittent power supply (blown fuses or poor ground), and age-related electronic component failures (capacitors, solder joints). Units swapped between cars without proper diagnostic coding can exhibit limited functionality until they are correctly programmed.

Why Choose This Unit

This Continental OE head unit is the correct replacement for vehicles originally fitted with the RD4N1M system and preserves factory look and operation. It is suitable for mechanics and competent DIYers who can perform physical replacement and arrange required diagnostic coding.

OEM Continental RD4N1M head unit offering CD and MP3 playback, designed as a direct replacement for many Citroën and Peugeot models. This unit preserves original mounting, connectors and dashboard integration for a clean factory-like fit. Frequently searched by part numbers, it is intended for professional workshops and experienced DIY mechanics who perform vehicle electronics work and radio coding.

Technical Information

Manufacturer: Continental (Original Equipment for Citroën/Peugeot)
Model: RD4N1M CD
Product Codes: 9664769777, 657992
Additional Numbers: 657990, 657989, 657937, 657935, 657934, 6579PC, 96647697XT
Compatible Models: Citroën/Peugeot 207; 307 II; 807; C2; C3 I; C4; C8

Fitment And Use

This unit is an OEM-style replacement for the listed Citroën and Peugeot models. It mounts into the original radio slot and uses factory wiring plugs, retaining steering wheel control compatibility when properly coded. Many customers locate this radio by its product codes, so check the part number against the unit being replaced before installation.

Installation Recommendations

Before starting, always disconnect the negative battery terminal to avoid risk of short circuits or damage to vehicle electronics. Typical replacement steps:

• Carefully remove trim panels around the radio using appropriate plastic pry tools to avoid damaging the dash.
• Unscrew and slide the radio out of the cage, then disconnect antenna, power and speaker connectors.
• Transfer any brackets or harness adapters if required and connect the new unit in reverse order.
• Reconnect the battery only after the unit is secured and connectors are in place.

After mechanical installation, the radio must be programmed to the vehicle using diagnostic equipment to restore full functionality (coding and security pairing). If you do not have the required diagnostic tool, have the coding performed by a qualified workshop with PSA diagnostic capability.

Why Units Fail And Typical Lifespan

Head units like the RD4N1M can remain functional for many years, but failure rates increase with age and operating conditions. Common causes of malfunction include:

• Heat and prolonged sun exposure causing electronic component degradation.
• Moisture ingress or corrosion at connectors.
• Mechanical wear of the CD mechanism (sticking, skipping or failure to read discs).
• Power surges or interrupted supply during battery changes or jump starts causing software lockups.
• Aging capacitors or solder joints inside the unit.

Regular use, clean environment and careful battery handling extend service life.

Recommended Tools And Skills

Ideal for professional mechanics or experienced DIYers. Recommended tools include trim removal tools, Torx/screwdriver set and, for final commissioning, PSA-compatible diagnostic tool for coding. If steering wheel controls or other integrated functions are not working after installation, diagnostic coding is required.

Notes On Programming

This radio requires diagnostic programming to the vehicle to restore full functionality and security pairing. Make sure coding and initialization are performed by personnel with appropriate diagnostic equipment and experience.

Why Choose This Unit

If you want a factory-fit radio with CD and MP3 playback for your Citroën or Peugeot, the Continental RD4N1M offers direct compatibility with original dashboard integration and connector layout. Purchasing by part number listed above is common practice and helps ensure you receive the correct replacement unit.

Original Blaupunkt RD4 N1 MP3 car radio – 03 for Citroën/Peugeot (used). Ideal replacement for a non-functional unit in PSA models with on-board CAN network. Thanks to the OEM design, you will maintain full integration with the vehicle – controls on the steering wheel, displays on the on-board display, parking sensors and a hands-free/USB box (if it is in the car). Often searched under part numbers 9666403077, 6579FG, 6579PC.

Main advantages
– Original PSA/Blaupunkt part – no compromises in compatibility and sound
– CD/MP3 and RDS support, control on the steering wheel and display on the OEM display
– Full integration with BSI; possibility to set functions (parking sensors, amplifier, AUX/USB) by diagnostics
– Exact replacement for cars with RD4 – just adapt correctly (add to car)

Compatibility
– Citroën: C4 (I), other selected models with RD4 (e.g. C2, C3, C5 II, Berlingo B9) – always check against the OEM code
– Peugeot: 307 II (facelift), further cars with RD4 (e.g. 207, 308 I, 407, Partner B9) – always check against the OEM code
– Vehicle network: CAN (RD4)
– Physical compatibility: rear 1× Quadlock connector + 1× antenna connector (Fakra)
Tip: The surest verification is to compare the OEM numbers 9666403077, 6579FG, 6579PC and the connectors/old unit match.

Technical information
– Manufacturer/type: Blaupunkt RD4 N1 MP3 – 03
– Features: CD player with MP3 support, FM/AM tuner with RDS
– Power: approx. 4×15–20 W RMS (OEM standard)
– Communication: CAN-BUS, pairing via VIN (no PIN code)
– Connectivity: 1× Quadlock (power supply, speakers, CAN), 1× Fakra antenna
– Integration: OEM on-board display, control on the steering wheel; optional external amplifier (JBL) – set by diagnostics
– Part numbers (for search): 9666403077, 6579FG, 6579PC, RD4 N1 MP3

Important for assembly and coding
– The unit must be “added” to the car with diagnostics (e.g. Diagbox/Lexia/PP2000). Without VIN pairing, the radio will emit a warning tone (beep).
– As part of telecoding, set: body type, presence of parking sensors, external amplifier (JBL), AUX/USB, hands-free, etc.
– Recommended professional assembly and inspection of the condition of the connectors/installation in the car.

Package contents and condition
– Supplied as a bare RD4 car radio unit (without display, frame, steering wheel control, antenna or wiring).
– Used original part – see photos/specific condition. Compare with your old unit and OEM numbers before purchasing.

Search keywords
RD4 N1 MP3 Car Radio, Blaupunkt, 9666403077, 6579FG, 6579PC, Citroën C4, Peugeot 307 II, PSA OEM Car Radio, CD MP3, Quadlock, Fakra, CAN, Telecoding, VIN Matching.

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.

High-quality Blaupunkt RD4 CD OEM radio unit designed for a range of Citroën and Peugeot models. This unit is commonly fitted as original equipment and appears under multiple PSA part numbers, making it a frequent replacement for workshops and DIY enthusiasts. It supports CD playback, AM/FM radio and integrates with vehicle systems when properly programmed. Ideal for mechanics and home mechanics looking for a direct-fit replacement with genuine OEM cross-references.

Key Features

• OEM Blaupunkt RD4 CD unit used by Citroën/Peugeot.
• Supports CD playback and standard radio functions (AM/FM).
• Direct-fit replacement for multiple PSA models — plug-in electrical connectors and mounting points.
• Requires diagnostic coding/programming to restore full functionality and disable theft protection.
• Commonly searched by OE numbers (useful for fast lookup in parts systems).

Technical Information

• Manufacturer: Blaupunkt (OEM for Citroën/Peugeot)
• Model: Citroën C2, Citroën C3 (I), Citroën C4, Citroën C8, Peugeot 207, Peugeot 307 (II), Peugeot 807
• Product Codes: 9659138977, 9647521077, 9660646877
• Other Numbers: 657932, 6579PC

Compatibility And Fitment Notes

Fits a range of PSA vehicles where the RD4 CD radio was originally installed. Always check the physical connector layout and bracket positions when replacing to ensure plug-and-play installation. This radio is frequently listed under the OE numbers above and under model groups for Citroën and Peugeot compact and mid-size cars.

Installation Recommendations

– Before starting work, disconnect the vehicle battery to avoid short circuits and protect vehicle electronics.
– Remove trim panels and use the correct radio removal keys or tools to extract the unit without damaging the dash.
– Unplug all connectors carefully, note antenna and auxiliary leads, and transfer any OEM brackets or trim pieces to the replacement unit if necessary.
– Install in reverse order and ensure connectors seat fully. Reconnect the battery only after physical installation is complete.
– The radio must be coded/initialized with a PSA-compatible diagnostic tool (DiagBox/PP2000/Lexia) to unlock anti-theft protection and restore full functionality (steering wheel controls, presets, etc.).

Most Common Failure Reasons

• Anti-theft lock or coding mismatch after replacement — unit appears dead or limited until properly programmed.
• CD mechanism wear or mechanical failure from frequent use or foreign objects in the tray.
• Connector corrosion or poor grounding causing intermittent power or audio issues (common in older vehicles or after water ingress).
• Failed internal components such as display/backlight or power supply capacitors due to age and thermal stress.
• Blown fuse in the vehicle wiring or damaged antenna connection can mimic radio failure.

Practical Tips For Workshops

• Keep diagnostic equipment ready — many of these units require coding to clear theft lock and restore presets.
• Check fuses and connector pins before condemning the radio; many faults are simple to diagnose at the harness level.
• When supplying a used or exchanged unit, verify the part numbers match the vehicle’s original references to minimize programming issues.
• Label removed screws and trim pieces during disassembly to speed up reassembly and avoid dash rattles.

Keywords

Blaupunkt RD4 CD, Citroën radio, Peugeot radio, 9660646877, 9647521077, 9659138977, 657932, 6579PC, OEM radio replacement

Product Overview

The Blaupunkt RD4 CD head unit is a direct-fit radio for many Citroën and Peugeot vehicles and is frequently sought under OEM part numbers. This unit provides reliable AM/FM radio reception, CD playback and integrates with the vehicle’s existing wiring and controls. Ideal for professional workshops and competent DIY mechanics who need a robust replacement radio with original-style operation.

Compatibility

• Citroën C2
• Citroën C3 / C3 Pluriel
• Citroën C4
• Citroën C8
• Peugeot 207
• Peugeot 307 II
• Peugeot 807

Technical Information

• Manufacturer: Blaupunkt (OEM For Stellantis / Citroën & Peugeot)
• Model: RD4 CD
• Product Codes: 9647521077, 9659138977
• Other Numbers: 657932, 6579PC

Features & Function

The RD4 CD unit offers standard factory radio and CD functions designed to match factory controls and dashboard fitment. It uses the vehicle’s wiring harness and antenna connection and communicates with the vehicle electronics for correct operation of steering wheel controls and on-screen information where supported.

How Replacement Is Done

Replacement is straightforward for a trained technician: remove the trim surrounding the radio, undo the mounting brackets or screws, pull the unit out and disconnect the antenna, power and speaker connectors. Install the replacement unit by reversing the steps, ensuring all plugs are fully seated and the antenna connection is secure. After mechanical installation the radio must be coded/paired to the vehicle with diagnostic equipment to restore full functionality.

Installation Recommendations

• Disconnect Battery: Always disconnect the negative battery terminal before starting to avoid electrical damage.
• Preserve Wiring: Retain original connectors and wiring adapters; avoid cutting factory harnesses where possible.
• Coding Required: The Unit Must Be Coded To The Vehicle Using Diagnostic Tools. Coding/Initialization Is Recommended To Be Performed With PSA Service Tools (DiagBox / Lexia / PP2000) To Restore Features Like Steering Wheel Control And Anti-Theft Locking.
• Professional Help: If You Are Not Equipped With PSA Diagnostic Tools Or Lack Experience With Coding, Have The Unit Installed And Coded By A Professional Workshop.

Why This Part Commonly Fails

• Mechanical Wear: CD mechanism and laser assemblies degrade over time, causing read errors or failure to load discs.
• Button / Control Failure: Frequent use and exposure to dust can cause failing knobs, buttons, or the front panel electronics.
• Electrical Issues: Loose connectors, blown fuses, poor grounding or vehicle electrical spikes can interrupt power to the unit.
• Loss Of Coding / Memory Corruption: In some cases the unit will lose stored settings or require re-coding after battery disconnection or electronic faults.
• Environmental Damage: Moisture Ingress Or High Temperatures Can Accelerate Component Failure.

Useful Notes For Buyers

Search By Part Number: This radio is commonly searched by its OEM references (9647521077, 9659138977, 657932, 6579PC) — include these numbers when matching to your vehicle. Ensure The Unit Matches The Dash Aperture And Connector Type For Your Model Year. Retain Any Original Mounting Brackets Or Trim Pieces For Proper Fit.

Why Choose This Unit

Replacing with an RD4 CD ensures compatibility with factory controls and maintains the vehicle’s original appearance and user experience. For workshops and experienced DIYers it provides a cost-effective way to restore radio and CD functionality while keeping integration with vehicle systems intact.