My sons' 545i has been getting a recurring CEL with a low coolant temp code. I replaced the thermostat and the coolant temp sensor, but the problem persists.

My son lives pretty close to where he works, and I'm wondering if the problem is that the engine is not getting up to normal operating temperature repeatedly during the week, causing the DMU to think there is a problem and tripping the CEL.

Anybody experience something similar?