jannik_lehmann7

SMAX Overheating and Communication Error

I'm having a nightmare with my 2009 Ford SMAX (gasoline engine). The engine's overheating like crazy, and the check engine light is constantly on. I even found coolant leaking under the car, which I'm guessing is because of too much pressure in the system. I plugged in a cheap OBD2 scanner and it's showing some kind of control unit communication error. Any ideas what's going on?

A 2009 Ford SMAX is experiencing severe engine overheating and a persistent check engine light, accompanied by a coolant leak likely due to excessive system pressure. An OBD2 scanner reveals a U0100 error code, indicating a communication issue with the ECM/PCM. The problem is traced to a corroded connector on the engine control unit, which is resolved by cleaning and replacing the connector at a garage.

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4 comment(s)

Sounds rough. Had similar symptoms on my old BMW 3 Series a few years back. What specific error codes are you getting from the scanner? Is it intermittent, or constant?

Hey, thanks for the reply! The error code I'm getting is U0100 - Lost Communication with ECM/PCM 'A'. It seems to be pretty constant, showing up every time I clear it and restart the engine. Is that what you were seeing on your BMW?

U0100 points to a CAN bus issue, or a faulty module. While my BMW was throwing a different code, the root cause was a corroded connector on one of the control modules. Best bet is to get it properly diagnosed at a workshop. They can check the wiring and modules properly.

Thanks for the advice. I took it to a local garage and they ran a full diagnostic. Turns out it was a corroded plug on the engine control unit, like you suspected! They cleaned it up and replaced the connector. Cost me 95€, but at least it's fixed. Appreciate the help!

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FORD

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SMAX