The brief
Desmond's 640i came in for its service, and the inspection flagged the battery as getting on, slow to crank, so he had it changed while the car was in. On a BMW a battery change isn't just a drop-in, the new one has to be registered with IBS, the battery management system, so the charging system knows it's fresh and charges it correctly. So it was a service plus a battery, done properly. A service runs through the whole car, oil and filters, fluids, brakes, suspension, electrics, a scan, and the battery test is part of it. When the battery's tired you change it, and on a BMW you code the new one in so the IBS recognises it. A worn battery doesn't recover, so it needs replacing and coding, the kind of thing that's worth seeing done right.
The diagnosis
The service check went through everything. The engine oil and filter were due, the air and cabin filters near the end, a couple of fluids wanting topping, and the battery test had it down, failing the load test and unable to hold voltage, the alternator charging fine. The brakes, belts, hoses and underbody checked out, no fault codes stored otherwise. So it was a service plus a battery replacement: the wear items refreshed, the fluids freshened, a fresh battery coded in with IBS.
The work
The engine oil was drained and refilled with the correct BMW-spec oil and a new oil filter fitted, the air and cabin filters replaced, the fluids topped, and a full diagnostic scan run. The old battery was removed and a new genuine BMW battery of the correct type and rating fitted, the terminals cleaned and the clamp torqued, then registered with IBS so the charging system recognised it as fresh, and the low-voltage faults cleared. A quick run confirmed a clean start, steady running, a strong crank, steady voltage, and nothing leaking.
The outcome
A clean bill of health on the 640i, fresh oil and filters, fluids topped, a clean scan, and a strong start on a fresh battery registered with IBS. The car went home serviced and sorted. A tired battery turns into a no-start, and on a BMW the new one has to be coded in, so doing the service and the battery together with the IBS coding done properly put it right in one visit.
