Speedometer with odometer and trip meter
| Speedometer with odometer and trip meter |
The main instrument unit is fitted with an electronic speedometer. The ABS control module receives information on vehicle speed from the rear left-hand wheel speed sensor. This information is processed and conveyed continuously to terminal 10 (K12) of the main instrument unit's control module.
The information, which is in the form of a square wave pulse, varies periodically between B+ and 0 V. The main instrument unit supplies current to the output and the ABS control module grounds it. This happens 29 times during each wheel revolution.
With the wheels stationary, the voltage may be either B+ or 0 V.
The main instrument unit uses the frequency to calculate the vehicle speed.
The speedometer is supplied with current and controlled by the main instrument unit's control module which converts the frequency-modulated signal to km/h. This is then corrected in accordance with the programmed tyre size, following which the speed information sent out on the bus.
| Odometer/trip meter |
The main instrument unit's control module stores the distance driven and shows it on the odometer display. The display contains a six-digit counter which the control module continuously updates from 000000 to 999999 km (or miles). The trip meter has a four-digit counter which starts at 000.0 and runs to 999.9 km (or miles). With the ignition ON, the trip meter is zeroized with the reset button. The display will be activated for 20 seconds if the reset button is pressed with the ignition OFF. An odometer reading is then obtained.
The main instrument unit sends distance driven information out on the bus. This information is used by the SID unit.
Diagnostics
If the vehicle speed information exceeds 270 km/h, diagnostic trouble code B1705 is set.This project is supported by memberships and donations. If you use this site, please consider Joining SCNA and/or making a donation.
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