Electrical system 9119 · 9003 Analogue speedometer General information on on-bo

Electrical system 9119 9003 Analogue speedometer General information on on-board computer func- tions The speed of all four wheels is used to de- termine the vehicle speed. The speed signal Range on remaining fuel is transmitted from the PSM control unit to the instrument cluster via the CAN interface. During a journey, the range on remaining If a wheel-speed fault is detected for one of fuel is continuously recalculated based on the wheels (e.g. faulty wheel-speed sensor), the fuel content of the fuel tank, and current the vehicle speed is determined using the and average consumption. speed signals from the remaining wheels. The display reacts more spontaneously as the level of fuel in the tank drops. For this reason, ranges below 15 kilometresSpeedometer A output (speed signal) (9 miles) are not displayed. The speedometer A signal continues to be generated as long as term. 15, term. 58 or The varying inclination of the vehicle during term. 86 S is switched on. the journey or when refuelling may lead to The output frequency is derived directly imprecise range information. from the determined wheel speed. As before, the speedometer A signal supplies Note 8 pulses per wheel revolution. If a nearly empty tank is refuelled with only a small amount of fuel, this is not registered 1709 Sensor for oil level indicator for the calculation of the remaining fuel range. A sensor (probe) which consists of a heating wire and simultaneously functions as a PTC Average consumption and average speed (electrothermal measuring method) is used to measure the oil level. The displayed values refer to the journey The sensor is installed in the engine. It is made since the average consumption and immersed in the oil and is briefly energised average speed displays were last reset to during the measuring process. zero. It is possible to determine the oil level from It is possible to set the starting point for the start and end voltage of the energisation measurement before or during the journey. phase. The measurements are not reset when the ignition is switched off. The values can, therefore, be collected over long periods. The average consumption and average speed memories are erased if the vehicle battery is disconnected. Outside temperature The outside temperature display should not be used as an ice warning. The road surface may be icy even if tem- peratures above 0 °C are displayed. 9 - 14 Service Information 2002