Mini Clubman Diesel Control Unit Communication Error

Overheating, coolant loss, and a check engine light on your Mini Clubman diesel sounds serious. A control unit communication error could definitely be the culprit, especially if it's affecting the cooling system. When you say "control unit communication error," do you have a specific diagnostic trouble code (DTC) you can share? Knowing the exact code would help narrow down the potential issues. Also, have you checked for any obvious signs of damage to the wiring harness or connectors related to the engine control module (ECM)?

The car diagnostics indicated a communication fault on the CAN bus. I've visually inspected the wiring loom around the ECM and haven't spotted anything obvious – no chafing, corrosion, or loose connections. Is there a specific component or area known to be problematic on these models that I should focus on?

A CAN bus communication fault with those symptoms definitely points towards a potential wiring issue or a failing control module. The CAN bus, or Controller Area Network, is how different electronic control units (ECUs) in your car communicate with each other. If there's a break in the communication, it can cause all sorts of problems. Given you've checked the ECM wiring, it might be worth having a workshop perform a more in-depth car diagnostics to pinpoint the exact source of the communication breakdown. It could be a faulty sensor, a damaged wire somewhere else in the harness, or even a failing control module itself.

Confirmed. Root cause traced to a defective plug connection on a control module. Seems the CAN bus was being disrupted intermittently. Replacing the connector and associated wiring solved it. Total cost was 95€. Thanks for the pointers.