Description
Main Engine Wiring Harness 1.6 e-HDI For Citroën C4 Picasso
This used main engine wiring harness is designed for 1.6 e-HDi petrol/diesel engines fitted to selected Citroën and Peugeot models. It restores the electrical backbone between the Engine Control Unit and essential components, ensuring reliable power distribution and signal transmission for injectors, sensors and actuators. Ideal for professional workshops and experienced DIY mechanics searching by OE number, this harness is a cost-effective way to repair electrical faults caused by damaged wiring or connectors.
Application And Fitment
Compatible With: Citroën C4, Citroën C4 Picasso, Peugeot 308 (1.6 e-HDi engine variants). Fitment must be confirmed against the vehicle’s OE part numbers listed below. The harness is intended as a direct replacement for vehicles using the corresponding Stellantis OE codes.
Technical Information
Manufacturer: Stellantis (Citroën / Peugeot)
Model: 1.6 e-HDi Engine Wiring Harness — Citroën C4 Picasso, Citroën C4, Peugeot 308
Product Codes: 9674051780, 9670855680, 9678303980
Additional Numbers: 6585L0
What The Harness Does
The main engine wiring harness routes power and data signals between the engine management system and components such as fuel injectors, pressure and temperature sensors, alternator/starter circuits, and various actuators. A correctly fitted harness ensures stable sensor readings and uninterrupted communication with the ECU, preventing misfires, limp-home modes and electrical faults.
Common Failure Modes And Frequency
Wiring harnesses do not have a fixed replacement interval. Failures typically appear after many years or high mileage, or sooner if the wiring is exposed to harsh conditions. The most common causes are connector corrosion, chafing against metal parts, heat-related insulation degradation, water ingress, mechanical damage from previous repairs or routed cable stress. Rodent damage can also be a frequent cause in parked vehicles. Symptoms include intermittent faults, injector failures, sensors reporting implausible values and engine warning lights.
Installation Recommendations
– Always disconnect the battery before beginning work to avoid short circuits and protect electronic modules.
– Carefully document or label connector locations before unplugging; take photos to ensure correct reconnection.
– Route the harness following original clips and grommets; replace any damaged clips and firewall grommets to prevent chafing and water ingress.
– Secure connectors firmly; inspect and clean mating surfaces. Use appropriate dielectric grease on exposed connector pins to reduce the risk of corrosion.
– Verify all ground straps and earth points are clean and tight.
– After installation, clear any stored fault codes and perform a functional check using an OBD diagnostic tool to confirm sensor readings and injector operation.
Why This Part Is Often Replaced
Engine wiring harnesses are subject to heat cycles, vibration and environmental exposure that progressively degrade insulation and connector integrity. Damage is often localised around engine mounts, turbocharger or exhaust regions where temperatures are highest, or where cables are pinched by previous repairs. Replacing a faulty harness is a common and effective repair to eliminate recurring electrical faults and restore reliable engine management operation.
Notes For Buyers
This is a used OEM wiring harness offered with the OE numbers shown above. Verify that one of the listed product codes matches the part being replaced on the vehicle to ensure correct fitment. Suitable for professional installation; recommended for experienced mechanics and competent DIYers familiar with engine-level electrical work.
