PRE-RELEASE
Programming the Speedometer
| Programming the Speedometer |
The ABS control module reads 29 impulses for each wheel revolution. Depending on the size of the tyres and rims (physical circumference), one kilometre will correspond to a different number of impulses when the main instrument unit receives the ABS value. Therefore, it is possible to change how the main instrument unit interprets the total number of impulses per kilometre so that they correspond to the size of tyre fitted on the car. Programming must take place so that the speedometer and odometer will display the correct information to the driver. In many countries, it is a legal requirement that the speedometer show between 0 and 10 km/h too much.
| Note | ||
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If the speedometer is not correctly programmed, the speed displayed to the driver can be lower than the actual road speed and SID will give erroneous information on the fuel quantity and time of arrival. |
Current tyre size is programmed using Tech 2. There are three types of tyre to choose from. Tyre type 1 has the largest circumference and tyre type 3 the smallest.
If the speedometer is programmed for a certain tyre type and new wheels with larger circumference are fitted, the speedometer will show a speed that is tool low compared with the desired speed display.
| Important | ||
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The car must be approved for fitting 17" wheels. |
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Tyre types in Tech 2:
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Type 1
215/45 R17 |
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Type 2
205/50 R16 |
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Type 3
195/60 R15 |
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