Programming Speedometer

The ESP control module reads 29 pulses per wheel revolution. Depending on the dimensions of the tire and rim (physical circumference), one kilometer will correspond to a different number of pulses when the main instrument unit receives the value from ESP. It is therefore possible to change how the main instrument unit interprets the total number of pulses per kilometer so they correspond to the tire dimension fitted on the car. Programming must be carried out so that the speedometer and odometer can give the driver the correct information. On certain markets, it is a legal requirement that the speed the speedometer shows is between 0 and 10 km/h too high.

NOTE: If the speedometer is not programmed correctly, the speed that is displayed to the driver may be lower than the actual speed and SID will provide incorrect information on the fuel quantity and time of arrival.

Fig 1: Programming Speedometer

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The current tire dimension is programmed with Tech 2. Select the correct tire from the list in Tech2 or choose to program the dynamic circumference of the tire manually.

If the speedometer is programmed for a certain tire and new wheels with larger circumference are fitted, the speed indicated by the speedometer will be too low.