Main code 56 indicates a failed range verification speed sensor ratio test. Range verification ratio test (between shifts) 5 The ratio test occurs after a shift and determines if a clutch has lost torque carrying capability. If output speed is above programmed output speed for a range but the correct speed sensor ratio is not present, the DO NOT SHIFT response is commanded and a range which can carry the torque without damage is commanded or attempted. Turbine and output speed sensor readings are used to calculate the actual ratio that is compared to the commanded ratio. Main code 56...

Main code 56 indicates a failed range verification speed sensor ratio test. Range verification ratio test (between shifts) 6 The ratio test occurs after a shift and determines if a clutch has lost torque carrying capability. If output speed is above programmed output speed for a range but the correct speed sensor ratio is not present, the DO NOT SHIFT response is commanded and a range which can carry the torque without damage is commanded or attempted. Turbine and output speed sensor readings are used to calculate the actual ratio that is compared to the commanded ratio. Main code 56...

Main code 56 indicates a failed range verification speed sensor ratio test. Range verification ratio test (between shifts) R The ratio test occurs after a shift and determines if a clutch has lost torque carrying capability. If output speed is above programmed output speed for a range but the correct speed sensor ratio is not present, the DO NOT SHIFT response is commanded and a range which can carry the torque without damage is commanded or attempted. Turbine and output speed sensor readings are used to calculate the actual ratio that is compared to the commanded ratio. Main code 56...

Main code 57 indicates failure of the range verification C3 pressure switch test. Range verification C3 pressure switch while in 1st. The test occurs when a range is commanded that does not use the C3 clutch (neutral, 1, 2, 4, and 6). The code is set if the C3 pressure switch is closed when it should be open. If C3 clutch comes on when not needed, three clutches are applied and a transmission tie-up occurs. The ECU will command a range which does not use the C3 clutch and activate the DO NOT SHIFT response. Allison WTEC II Fault Code:...

Main code 57 indicates failure of the range verification C3 pressure switch test. Range verification C3 pressure switch while in 2nd. The test occurs when a range is commanded that does not use the C3 clutch (neutral, 1, 2, 4, and 6). The code is set if the C3 pressure switch is closed when it should be open. If C3 clutch comes on when not needed, three clutches are applied and a transmission tie-up occurs. The ECU will command a range which does not use the C3 clutch and activate the DO NOT SHIFT response. Allison WTEC II Fault Code:...