Speedometer with odometer and trip meter (TC/ABS)
| Speedometer with odometer and trip meter (TC/ABS) |
The main instrument unit has an electronic speedometer. The TC/ABS control module receives speed information from all the wheel speed sensors. The information is processed and sent continuously to the P-bus. The main instrument unit reads the speed information from the rear left wheel and converts it to km/h. Information from the rear right wheel will be used if information from the rear left wheel is missing.
The information from the wheel sensors to TC/ABS is a square wave pulse that varies periodically between B+ and 0V. This takes place 29 times per wheel revolution.
With the wheels stationary, the voltage may be either B+ or 0 V.
The speedometer stepping motor is pulsed and controlled internally by the main instrument unit control module, which also forwards the speed information to the bus.
| Odometer/trip meter |
The main instrument unit control module stores the distance covered and shows the mileage on the odometer display. The display has a six-digit counter which the control unit continuously updates from 000000 to 999999 km (or miles). The trip meter has a four-digit counter which starts at 000.0 and goes up to 999.9 km (or miles). The trip meter is zeroed when the ignition is turned to ON. The display will come on for 20 seconds if the reset button is pressed and the ignition is OFF so that the odometer reading is made visible.
Information on the driven distance is sent to the buses by the main instrument unit. The information is used by e.g. SID.
Diagnostics
If the vehicle speed information exceeds 270 km/h, diagnostic trouble code B1705 is set.The function has its own diagnostics in the sending system.
This project is supported by memberships and donations. If you use this site, please consider Joining SCNA and/or making a donation.
Our Friends
