Allison
Allison WTEC II Fault Code: 54 PID: SPN: 71 FMI: Oncoming ratio test (after shift), R to 1
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. R?1 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...
Allison WTEC II Fault Code: 54 PID: SPN: 72 FMI: Oncoming ratio test (after shift), R to 2
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. R?2 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...
Allison WTEC II Fault Code: 54 PID: SPN: 80 FMI: Oncoming ratio test (after shift), N1 to L
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 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 during a...
Allison WTEC II Fault Code: 54 PID: SPN: 81 FMI: Oncoming ratio test (after shift), N1 to 1
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. N1?1 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...
Allison WTEC II Fault Code: 54 PID: SPN: 82 FMI: Oncoming ratio test (after shift), N1 to 2
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. N1?2 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...
