Vehicle speed
Vehicle speed |
The ABS control module sends a vehicle speed signal to pin 39 of the Trionic ECM. The signal is a square-wave which varies between 0 V and Batt+ 29 times/ wheel rotation. This speed signal is used to:
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decide which gear is engaged at
the time
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activate the SHIFT UP lamp (does not apply to 5th gear)
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limit the boost pressure in Reverse, 1st and 2nd gears
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activate fuel shut-off in 3rd, 4th and 5th gears
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activate speed limiting (by limiting the boost pressure at 230 km/h)
If there is no speed signal, the above functions do not occur and the boost pressure, on cars with manual transmission, is limited. |