Technician Handbook ! 673 Electronic & Computer Controlled Systems Customization No matter how carefully automobile manufacturers analyze the features that new car buyers want, there will always be those who want a feature to work differently. ECUs have made it much easier for owners to customize many of the vehicle’s convenience features to suit their own preferences. The settings for customizable features are stored in ECU memory. Needless to say, if the memory is lost then any preferences the owner has chosen are also lost. Memory can be lost when the ECU loses its connection to the battery, and also when the ECU is replaced.
SERVICE TIP Before disconnecting the battery, make note of the owner’s customized settings and restore those settings when service is complete. NOTE When one driver changes a customized setting without informing other drivers, another driver may view the change in operation as a malfunction. Be sure to consider the potential role of customized settings on a customer’s concern before beginning a problem diagnosis. 20 Technical Training