Description
Automatic Transmission Control Unit – Siemens SV_BVA_TA2005_CEM0
Suitable for Citroën C4 and Peugeot 307
This Siemens TA2005 transmission ECU is a direct-fit control unit for automatic gearbox management on selected Citroën C4 and Peugeot 307 models. Designed for professional workshops and experienced DIY mechanics, the unit controls shift logic, torque converter lock‑up and adaptive learning to ensure smooth gear changes and optimal drivability. The part is often searched by its product codes (e.g. 9659838680), so listing the reference numbers helps technicians and parts buyers find the correct unit quickly.
Key Benefits
Reliable control of automatic shifting behavior with factory‑level logic. Reduces Gear Hunting And Improves Fuel Efficiency When Properly Configured. Straightforward replacement for compatible vehicles when paired with the correct diagnostic procedures and adaptation.
Technical Information
- Manufacturer: Siemens
- Model: SV_BVA_TA2005_CEM0 (TA2005)
- Product Codes: 9659838680, S126024101
- Other Numbers: 9661983980, 253034
- Application: Citroën C4; Peugeot 307 (verify model/engine/code before installation)
Installation Recommendations
Follow these steps to reduce the risk of damage and to ensure correct operation after fitment:
- Disconnect the negative battery terminal before any work to prevent electrical damage and short circuits.
- Observe electrostatic discharge (ESD) precautions when handling the ECU; avoid touching connector pins directly.
- Inspect wiring harnesses and connectors for corrosion, bent pins or water ingress; repair any damaged wiring before installation.
- Fit the unit securely using the original mounting points; ensure connectors are fully engaged and locking tabs are in place.
- After mechanical installation, perform gearbox adaptation/learning and any required coding using an appropriate PSA diagnostic tool (e.g. DiagBox/Lexia) to restore full functionality.
- Always consult the vehicle manufacturer’s workshop manual for location, removal torque values and specific procedures for the exact model and year.
Why This Part Fails Most Often
Transmission ECUs commonly fail due to electrical and environmental stresses rather than purely mechanical wear. Typical causes include:
- Water Ingress Or Corrosion In Connectors Leading To Short Circuits Or Intermittent Signals.
- Thermal Stress And Repeated Heating/Cooling Cycles Causing Component Or Solder Joint Failures.
- Voltage Spikes Or Poor Grounding Which Damage Internal Electronics.
- Vibrations And Mechanical Shock Over Time That Loosen Internal Components.
- Secondary Damage From Faulty Sensors Or Wiring Causing Abnormal Loads On The Unit.
Common Symptoms Of A Failing Transmission ECU Include Erratic Shifting, Gear Slippage, Transmission In Limp Mode, Illuminated Gearbox Faults (Check Engine Or Transmission Warning Lamps), And Stored Diagnostic Trouble Codes Related To Gearbox Control.
