Theory Of Operation
WARNING: This page is about a different variant/trim than selected.
The purpose of the diagnostic is to detect rationality failures of the Input Speed Sensor signal. This diagnostic checks if the Input Speed Sensor signal is within the calculated tolerance bands:
- The upper threshold of the first tolerance band is the greater value of either the engine speed or calculated input speed, plus a calibrated offset. The calculated input speed is based upon the output speed signal multiplied by the gear ratio factor. This factor corresponds to either the target gear or current gear depending on which gear provides the greater ratio.
- The lower threshold of the first tolerance band is the lesser value of either the engine speed or calculated input speed, minus a calibrated offset. The calculated input speed is based upon the output speed signal multiplied by the gear ratio factor. This factor corresponds to either the target gear or current gear depending on which gear provides the lesser ratio.
- The thresholds of the second tolerance bands are calculated using the same method described above. In place of the output speed signal, the wheel speed signal via BUS is used for the calculation.
| 1 - Upper threshold of first tolerance band (Calculated input speed from output speed plus a value) | 6 - Wheel Speed |
| 2 - Upper threshold of second tolerance band (Calculated input speed from wheel speed plus a value) | 7 - Engine speed |
| 3 - Input Speed | 8 - Lower threshold of first tolerance band (Calculated input speed from output speed plus a value) |
| 4 - Engine speed upper threshold | 9 - Lower threshold of second tolerance band (Calculated input speed from wheel speed plus a value) |
| 5 - Output Speed | 10 - Lower threshold of first/second tolerance band (Engine speed minus a value) |