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.