Theory Of Operation

This diagnostic checks the rationality of the actual odd clutch speed with four different tests. When one of these tests fail the diagnostic will be considered failing. The first diagnostic verifies that the actual odd clutch speed is different from the sensor reading of 0 RPM in three different vehicle situations. The first situation is verified when the odd clutch is closed and the actual gear is not the Neutral. The second situation is verified when the odd clutch is closed beyond the touch point (the "touch point" is defined as the point where the clutch first touches the flywheel, but short of the full clutch engagement position). The third situation is verified when the driveline speed is above a threshold and the actual gear is an odd gear (1st, 3rd, 5th or Reverse). The second diagnostic verifies that the rate of change of the odd clutch speed varies within a calibrated limit. The third diagnostic compares the odd clutch speed signal to the engine speed and to an estimated clutch speed when the odd clutch is closed, there is no gear shift in progress and the actual gear is an odd gear (1st, 3rd, 5th or Reverse). The fourth diagnostic compares the odd clutch speed signal to an estimated clutch speed when the driveline speed is above a threshold and the actual gear is an odd gear (1st, 3rd, 5th or Reverse).