Allison
Allison WTEC II Fault Code: 51 PID: SPN: 46 FMI: Offgoing ratio test (during shift), 4 to 6
Posted by PerDiezel Solutions on
Main code 51 indicates a failed offgoing ratio test. 4?6 upshift An offgoing ratio test occurs during a shift and uses turbine and output speed sensor readings to calculate the ratio between them. The calculated speed sensor ratio is then compared to the programmed speed sensor ratio of the commanded range. After a shift is commanded, the ECU, after a period of time, expects the old ratio to be gone. If the ratio does not change properly, the ECU assumes the offgoing clutch did not release. The shift is retried if conditions still exist to schedule the shift. If the...
Allison WTEC II Fault Code: 51 PID: SPN: 53 FMI: Offgoing ratio test (during shift), 5 to 3
Posted by PerDiezel Solutions on
Main code 51 indicates a failed offgoing ratio test. 5?3 downshift An offgoing ratio test occurs during a shift and uses turbine and output speed sensor readings to calculate the ratio between them. The calculated speed sensor ratio is then compared to the programmed speed sensor ratio of the commanded range. After a shift is commanded, the ECU, after a period of time, expects the old ratio to be gone. If the ratio does not change properly, the ECU assumes the offgoing clutch did not release. The shift is retried if conditions still exist to schedule the shift. If the...
Allison WTEC II Fault Code: 51 PID: SPN: 64 FMI: Offgoing ratio test (during shift), 6 to 4
Posted by PerDiezel Solutions on
Main code 51 indicates a failed offgoing ratio test. 6?4 downshift An offgoing ratio test occurs during a shift and uses turbine and output speed sensor readings to calculate the ratio between them. The calculated speed sensor ratio is then compared to the programmed speed sensor ratio of the commanded range. After a shift is commanded, the ECU, after a period of time, expects the old ratio to be gone. If the ratio does not change properly, the ECU assumes the offgoing clutch did not release. The shift is retried if conditions still exist to schedule the shift. If the...
Allison WTEC II Fault Code: 51 PID: SPN: 65 FMI: Offgoing ratio test (during shift), 6 to 5
Posted by PerDiezel Solutions on
Main code 51 indicates a failed offgoing ratio test. 6?5 downshift An offgoing ratio test occurs during a shift and uses turbine and output speed sensor readings to calculate the ratio between them. The calculated speed sensor ratio is then compared to the programmed speed sensor ratio of the commanded range. After a shift is commanded, the ECU, after a period of time, expects the old ratio to be gone. If the ratio does not change properly, the ECU assumes the offgoing clutch did not release. The shift is retried if conditions still exist to schedule the shift. If the...
Allison WTEC II Fault Code: 51 PID: SPN: XY FMI: Offgoing ratio test (during shift), X to Y
Posted by PerDiezel Solutions on
Main code 51 indicates a failed offgoing ratio test. X to Y shift An offgoing ratio test occurs during a shift and uses turbine and output speed sensor readings to calculate the ratio between them. The calculated speed sensor ratio is then compared to the programmed speed sensor ratio of the commanded range. After a shift is commanded, the ECU, after a period of time, expects the old ratio to be gone. If the ratio does not change properly, the ECU assumes the offgoing clutch did not release. The shift is retried if conditions still exist to schedule the shift....
