Description
Main Engine Wiring Harness 1.6 e‑HDi for Citroën C4 Picasso.
This genuine-style engine wiring harness is designed for 1.6 e‑HDi diesel engines used in Citroën and Peugeot models. It links sensors, injectors, actuators and the engine control systems, ensuring reliable communication and power distribution across the engine bay. Supplied with original reference numbers 9674051780, 9670855680 and 6585L0 (cross reference 9678303980), this harness is a direct-fit replacement for vehicles in the Stellantis group and is aimed at professional garages and experienced DIY mechanics who maintain Citroën C4, C4 Picasso and compatible Peugeot models such as the 308. Including the correct OE codes in your search will significantly improve findability and compatibility matching.
Technical Information
- Manufacturer: Stellantis
- Model: Citroën C4; Citroën C4 Picasso; Peugeot 308 (1.6 e‑HDi)
- Product Codes: 9674051780, 9670855680, 6585L0
- Additional Numbers: 9678303980
Function And Application
The engine wiring harness routes power and signals between the engine control unit, fuel injectors, common‑rail system components, glow plugs, sensors (such as crankshaft position sensor, coolant temperature sensor, MAP/pressure sensors) and engine actuators. Correct connector orientation, secure grounding and intact insulation are essential for stable engine management and emissions control.
Replacement Procedure
Replacement typically requires moderate mechanical experience and common workshop tools. Typical steps:
- Park the vehicle on a level surface, engage the handbrake and disconnect the negative battery terminal.
- Remove obstructing components as required (airbox, battery tray, engine covers) to gain clear access to the harness routing.
- Carefully label and disconnect all electrical connectors, vacuum lines and earths from the old harness—note routing clips and protective conduit.
- Unclip the harness from brackets and grommets and withdraw the old loom, taking care not to damage nearby components.
- Install the new harness following factory routing, secure all clips, reconnect connectors and restore removed components.
- Reconnect the battery and perform a controlled engine start. Check for fault codes and test all related functions (idle, cold start, warning lights).
Estimated fitment time for an experienced mechanic: 1.5–3 hours depending on vehicle access and additional parts removal.
Installation Recommendations
- Always Disconnect The Battery Before Starting Work To Avoid Short Circuits And Potential Damage.
- Inspect Connector Pins And Seals For Corrosion Or Damage Before Reuse; Replace Any Compromised Clips Or Grommets.
- Use Correct Cable Ties And Mounting Clips To Prevent Chafing Against Engine Components Or Sharp Edges.
- When Reconnecting, Ensure Connectors Click Securely And Any Sealing Boots Are Properly Positioned To Prevent Moisture Ingress.
- After Installation, Clear Relevant Fault Codes And Monitor For Intermittent Faults; Load The Engine To Confirm Stable Operation.
Common Failure Reasons
- Heat Damage: Prolonged exposure to high under‑bonnet temperatures can harden insulation and cause cracks or short circuits.
- Mechanical Wear: Vibration and movement can lead to chafing at attachment points, resulting in exposed conductors or broken cores.
- Corrosion And Moisture Ingress: Damaged seals or wet conditions can corrode connector pins and cause poor contacts or intermittent faults.
- Rodent Damage: Chewing can sever wires or damage protective sheathing, particularly on parked vehicles.
- Connector Failure: Bent or pushed‑out pins and damaged latches cause signal loss to sensors and actuators, leading to engine misfires, rough idle or fault codes.
Symptoms Of A Faulty Engine Wiring Harness
Owners or technicians may observe multiple warning lights, rough running, misfires, loss of power, failed injector circuits, or engine management codes relating to sensors and actuators. Intermittent faults that change with engine temperature or vehicle movement often point to wiring or connector issues rather than sensors themselves.
Compatibility And Search Tips
When searching for this part, use OE numbers 9674051780, 9670855680, 9678303980 or 6585L0 together with vehicle keywords (Citroën C4, C4 Picasso, Peugeot 308, 1.6 e‑HDi) to narrow results. Professional installers should verify engine code and build year to ensure correct routing and connector variants.
Final Notes
This wiring harness is intended as a direct replacement for the listed models and part numbers. Proper installation and securing of the harness are crucial for long service life; do not route the wiring near hot exhaust components or sharp edges without protective sleeving.
