Relative Time

This telegram is made available to other control units by the instrument cluster for time calculations. A timer counts the seconds synchronous to the system/vehicle clock. This signal can be used to measure relative times. The clock cannot be used for this purpose, as it can be set by the customer.

The counter runs following reset (e.g. disconnecting the battery) from 0 and counts in second increments from 0 to over 4 billion, which corresponds to approximately 140 years.

The DME (ECM), for example, needs the relative time to determine the immobilization period of the engine (engine OFF) and thus to improve the starting capability of the engine. The immobilization period is calculated by the DME (ECM) from the relative time of terminal R OFF to terminal R ON again.