BMAX Control Unit Communication Error

Good day. I am writing to this forum to seek assistance with a problem I am experiencing with my vehicle. It is a 2012 Ford BMAX, diesel engine, with 182013 km on the clock. I am encountering a perplexing issue related to a control unit communication error. The symptoms manifest as overheating of the engine, accompanied by the check engine light illuminating on the dashboard. Furthermore, I have observed coolant spilling under the vehicle, indicative of excessive pressure within the cooling system. My initial assessment, based on available resources, suggests a potential defect within the cable or plug connection of the component. Could a software glitch also trigger this behaviour? Any insights would be greatly appreciated.

4 comment(s)

Interesting issue. I have a BMAX as well. Those symptoms do suggest a few possibilities. The overheating coupled with the coolant spill makes me think it's more than just a software issue, although a wonky control unit can cause all sorts of havoc. Have you had a diagnostic trouble code (DTC) read from the car's computer? It could point you to the specific control unit that's causing the problem. Was the coolant spill recent?

Thank you for your reply. Yes, I had a diagnostic scan performed, and it indicated a communication error with one of the control units, but it was not specific which unit. The coolant spill is a rather recent development, occurring simultaneously with the overheating episodes and the check engine light activation. Does that clarify the symptoms further, or do you have any advice what component I should be checking first?

Alright, a vague communication error combined with a coolant leak... that's not ideal. I had a similar problem about a year ago, it turned out to be a corroded CAN bus connection near the engine control module. In my estimation, while you may be able to trace the wiring visually, without more specific diagnostic equipment, you will be unable to determine root cause of the electrical issue. Given the risk of further engine damage from overheating, and potential cost of different spare parts, perhaps have an experienced workshop technician investigate the car? This is likely the most effective way.

I appreciate the advice. Based on your experience and suggestions, I will take the vehicle to a reputable workshop for a thorough inspection. Indeed, I found a faulty plug (near the engine control module) and the workshop confirmed also a broken wire. The technician replaced the wire harness and cleaned up the plug, recoding the car's software. Total cost was 95€ . Thank you again for sharing your insights.

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