Allison
Allison WTEC II Fault Code: 54 PID: SPN: 54 FMI: Oncoming ratio test (after shift), 5 to 4
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 5?4 downshift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
Allison WTEC II Fault Code: 54 PID: SPN: 56 FMI: Oncoming ratio test (after shift), 5 to 6
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 5?6 upshift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
Allison WTEC II Fault Code: 54 PID: SPN: 64 FMI: Oncoming ratio test (after shift), 6 to 4
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 6?4 downshift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
Allison WTEC II Fault Code: 54 PID: SPN: 65 FMI: Oncoming ratio test (after shift), 6 to 5
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 6?5 downshift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
Allison WTEC II Fault Code: 54 PID: SPN: 70 FMI: Oncoming ratio test (after shift), R to L
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. R?L shift The ratio test after a shift is failed when the ECU has commanded the end of a shift and has not seen the transmission shift into the target range (comparing turbine and output speeds). Erratic readings from speed sensors are a likely cause of an oncoming ratio test failure. If conditions for a shift still exist, the shift will be retried one more time. If the ratio test is still not met, a code is logged and the DO NOT SHIFT response is commanded. If the code is set...
