DS4 Control Unit Communication Error

It sounds like a wiring issue. The symptoms you're describing could be related to a faulty cable or plug connection to one of the engine management components. The overheating and coolant spill, coupled with the check engine light, suggests the ECU might be receiving incorrect data, causing it to mismanage the cooling system. It's like a short circuit in your house, causing lights to flicker and appliances to malfunction. Have you checked the condition of the wiring harnesses and connectors around the engine? A visual inspection might reveal obvious signs of damage or corrosion.

Thanks. Regarding the wiring harnesses and connectors, is there a particular area or component I should focus on initially? I'm familiar with basic car diagnostics, but I'm not an expert in control modules. Could you suggest a starting place for my investigation?

Given the mileage and build year, focus on any connectors near the coolant temperature sensor and the thermostat housing first, as these are directly related to the overheating issue. Also check the main ECU connector itself. The vibration and temperature changes under the hood can cause connections to become loose or corroded over time. If those look okay, it may be necessary to get a professional diagnostic check as the problem may be more complex. Consider a workshop visit.

I appreciate your advice. You were spot on; it was indeed a defective cable at the component connection. A professional looked at it, and the cable was replaced. It seems excessive pressure in the cooling system was causing the coolant spill. Repair costs were 95€.