If you own or repair Citroën or Peugeot vehicles, this ECU is an excellent choice for replacing or repairing your existing unit. It offers reliable operation and comes from a trusted source of high-quality used auto parts, providing an affordable solution without compromising performance.

When replacing this ECU, it is highly recommended to consult with a professional technician to ensure proper installation and compatibility with your vehicle’s systems. Correct installation guarantees restored engine efficiency, smooth operation, and optimized fuel consumption.

Technical Information:

Manufacturer: Siemens
Model: Peugeot 407 2.0 HDI RHR
Product Codes: 9655534080, 9661835480, 5WS40264E-T, 1940ZR, 1942YL, 1942YN, 1940ZS
Additional Numbers: The extensive list of product codes allows easy verification of compatibility with your vehicle.

This ECU is vital for accurate fuel injection control and motor management. Common ECU failures can cause engine misfires, reduced power output, or increased fuel consumption. By replacing a faulty unit with this quality part, you can effectively resolve such issues and extend the lifespan of your Peugeot 407.

Take advantage of this opportunity to equip your vehicle with a professionally sourced and cost-effective replacement ECU, ensuring full functionality and reliability. Remember that proper installation and maintenance are key to sustaining your vehicle’s optimal performance over time.

Product Overview

This genuine Siemens fuel injection control unit (ECU) is designed for Peugeot 407 2.0 HDi engines with RHR injection systems. Ideal for professional workshops and experienced DIY mechanics, the unit matches common OEM numbers 5WS40167G-T, 9655041480 and 9656171180 and is suitable where part references such as 1940ZR, 1942YL, 1618G2, 1942YN or 1940ZS are requested. Replacing a faulty ECU restores engine management functions including injection timing, fuel quantity control and safety interlocks, helping to recover drivability and emissions performance.

Technical Information

• Manufacturer: Siemens
• Model: Peugeot 407 2.0 HDi (RHR)
• Product Codes: 5WS40167G-T, 9655041480, 9656171180
• Other Numbers: 1940ZR, 1942YL, 1618G2, 1942YN, 1940ZS

Function And Benefits

The ECU controls diesel injection timing, fuel metering and interacts with sensors such as crankshaft position, camshaft position, MAP and coolant temperature to ensure reliable engine operation. Replacing a malfunctioning unit can resolve issues such as rough idle, loss of power, frequent stalling, excessive smoke or failed diagnostics related to engine management. Using a correctly coded or cloned unit keeps immobilizer functionality and prevents starting problems.

Replacement Procedure

General replacement steps for experienced technicians:

• Disconnect Battery: Always isolate the battery before starting to avoid electrical damage.
• Access Unit: Remove protective covers and locate the ECU (position can vary by model year and body configuration).
• Unplug Connectors: Carefully release locking tabs and disconnect wiring harnesses; inspect pins and seals for corrosion or damage.
• Remove Mounting: Unbolt the ECU from its bracket and remove it from the vehicle.
• Install New Unit: Fit the replacement, secure mounting, reconnect harnesses and covers, then reconnect the battery.
• Coding/Initialization: Unit will usually require cloning or programming to match the vehicle immobilizer and engine settings (see Installation and Coding – Important).

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. Virginization 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.

Why This Part Fails Most Often

• Water Ingress And Corrosion: Moisture penetrating connectors or casing causes short circuits and degraded solder joints.
• Thermal Stress And Ageing: Repeated heating cycles and age can lead to component failure or cracked solder traces.
• Electrical Faults: Voltage spikes, poor grounding or faulty alternator regulation can damage internal electronics.
• Connector Damage Or Contamination: Bent pins, oxide layers or contaminated seals lead to poor signal transfer and intermittent faults.
• Immobilizer Locking: ECU mismatch or lost immobilizer data prevents normal engine start without proper cloning or coding.

Installation Recommendations

• Check Related Systems First: Verify sensors, grounds and charging system to avoid repeated ECU failure.
• Inspect Connectors And Wiring: Clean or replace corroded plugs and ensure harness seals are intact.
• Use Proper Tools And Diagnostics: Perform cloning or coding with DiagBox/Lexia/PP2000 or equivalent to restore immobilizer and engine parameters.
• Handle With Care: Avoid touching connector pins, and protect the unit from static and mechanical shocks during installation.
• Document Original Unit: Note original part numbers and store removed unit safely in case cloning is required.

Compatibility And Keywords

Fits Peugeot 407 2.0 HDi (RHR) applications where part numbers 5WS40167G-T, 9655041480, 9656171180 or engine codes 1940ZR / 1942YL / 1618G2 / 1942YN / 1940ZS are specified. Useful search terms: Peugeot 407 ECU, Siemens SID803, 5WS40167G-T, 9655041480, 1940ZR.

Notes For Professionals

This description is intended for mechanics and experienced DIYers. Follow manufacturer service manuals and safety procedures when working on vehicle electronics. Proper cloning or programming is essential to restore full functionality and immobilizer compatibility.

Compatible models include the Peugeot 407 2.0 HDI RHR, ensuring high efficiency and smooth operation. Regular replacement of the ECU may be necessary due to wear and tear from continuous use, which can affect engine performance over time. This Siemens unit offers reliability and enhances the vehicle’s performance, making it an excellent choice for repairs and upgrades.

When replacing the ECU, proper installation is crucial. Mechanics should follow manufacturer specifications for disconnecting the battery and removing the old unit before installing the new ECU, ensuring all connections are secure.

Technical Information

• Manufacturer: Siemens
• Model: SID 803
• Product Codes: 5WS40167H-T, 9655041480
• Additional Numbers: 1940ZR, 1942YL, 1942YN, 1940ZS