Description
Car radio with CD RD4 D2 N2, has 2 antenna inputs. The radio must be coded to the vehicle using diagnostics. It is from Peugeot 407.
Product Overview
This original-equipment RD4 CD radio is a direct-fit audio unit taken from a Peugeot 407. It is a robust OE-style head unit designed for workshops and DIY mechanics who need a reliable replacement radio with CD playback and improved reception thanks to dual antenna inputs. The unit is widely searched by its product numbers, so listing the reference codes below will help you find the correct fit quickly.
Key Features
- RD4 D2 N2 CD head unit — factory standard for many PSA models
- Two Antenna Inputs — supports antenna diversity or connection to external aerial/amplifier systems for better reception
- CD Playback plus AM/FM radio functionality
- Designed as a direct OE replacement for vehicles originally fitted with RD4 units
- Supplied used (original vehicle unit) — requires diagnostic coding to enable full operation in the replacement vehicle
Technical Information
- Manufacturer: Stellantis / Peugeot-Citroën
- Model: RD4 D2 N2
- Product Codes: 9646871777, 7643141392
- Additional Numbers: 6564W5, 6564W6, 16085109YW
Compatibility
The unit originates from a Peugeot 407 and is intended as a replacement for vehicles originally equipped with the RD4 series radio. Many buyers search for this item using the product codes listed above. Ensure your vehicle originally used an RD4-type unit before installation to avoid wiring or coding issues.
Function And Behaviour
The RD4 radio provides CD audio playback and FM/AM reception. Dual antenna inputs improve signal quality and can support external amplifier connections or antenna diversity systems used on some PSA models. When installed and coded correctly, the unit integrates with vehicle audio systems and steering wheel controls where applicable.
Replacement Procedure (General Guide)
- Prepare tools: trim removal tools, radio removal keys (if required), Torx/screwdriver set.
- Disconnect the negative battery terminal before starting to avoid electrical damage or faults.
- Remove dashboard trim panels carefully to access the radio mounting frame.
- Unscrew and slide out the radio; disconnect the main harness, antenna connectors (note there are two), and any separate amplifier or CAN connectors.
- Fit the replacement unit by reversing removal steps. Secure mounting screws and refit trim panels.
- Perform diagnostic coding to pair the radio to the vehicle (see Coding section below).
Coding And Commissioning
This RD4 unit requires diagnostic coding to enable full functionality in the replacement vehicle. Without proper coding (performed with compatible PSA diagnostic tools), features such as radio enablement, display messaging and steering wheel controls may not work. Coding must be performed by a workshop with PSA-capable diagnostic equipment.
Installation Recommendations
- Always Disconnect The Battery Before Removal/Installation To Prevent Electrical Damage.
- Use Proper Trim Tools To Avoid Breaking Dash Clips And Finish Panels.
- Label Or Photograph Connectors Before Disconnecting To Ensure Correct Reassembly.
- Have A Professional With PSA Diagnostic Equipment Perform The Final Coding/Activation If You Do Not Have The Required Tools.
Why This Part Most Often Fails
Common causes of RD4 radio failures include:
- Mechanical Wear In The CD Mechanism — frequent use and age can cause the loader or laser assembly to fail.
- Moisture Ingress And Corrosion — water or humidity can corrode connectors or internal boards, especially when dash seals are compromised.
- Thermal Stress And Solder Joint Fatigue — repeated heating/cooling cycles can lead to cracked solder joints and intermittent faults.
- Connector Or Wiring Issues — poor contacts or damaged antenna leads reduce reception or cause the unit to lose power/functions.
Notes For Workshops And DIY Mechanics
Because the radio is an original PSA unit, installation and coding workflows are standard for Peugeot/Citroën workshops. Having the product codes to hand will speed up parts lookup and compatibility checks. This unit is ideal for mechanics looking for a cost-effective, direct-fit replacement for vehicles originally equipped with RD4 radios.
