Transit says oil level is low but the dipstick reads full - oil level sensor

A low oil level warning when the dipstick shows a full sump is a known issue on early Transit MK8 models. The usual cause is the oil level sensor in the sump or outdated ECU software that misinterprets its reading. Before replacing the sensor, make sure the opposite problem is not occurring. On vans used for short trips, frequent DPF regenerations can allow unburned diesel to enter the sump, causing the actual oil level to rise above maximum. Oil diluted with fuel loses its lubricating properties. In an engine with a wet timing belt, this can rapidly accelerate belt deterioration, so oil above the maximum mark must be replaced, not simply drained down to the correct level.