The fast-off identification function can also apply when the vehicle approaches a corner.
Rapidly releasing the accelerator may inhibit an upshift if the vehicle is not already in top gear.
But if upshift has been avoided by fast-off identification, it is still not desirable to upshift on the actual corner, even if the accelerator is depressed again.
So, upshifts are prevented when a pre-set rate of lateral acceleration is exceeded.
The radius of the curve is determined by comparing the rotating speeds of the inner, and outer front wheels, when the vehicle is not travelling in a straight line.
This data from the wheel sensors, added to road speed, allows a sufficiently accurate estimate of lateral acceleration.
If corners are taken at a particularly high rate of lateral acceleration, down-shifts are also inhibited.
For data from the wheel sensors to be accurate, it is essential the two front wheels have the same dynamic circumference.
This is monitored continuously by the diagnostic circuits. Any discrepancies, perhaps from different tyre pressures, will deactivate the corner identification.
