Allison
Allison WTEC II Fault Code: 54 PID: SPN: 42 FMI: Oncoming ratio test (during shift), 4 to 2
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 4?2 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: 43 FMI: Oncoming ratio test (after shift), 4 to 3
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 4?3 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: 45 FMI: Oncoming ratio test (after shift), 4 to 5
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 4?5 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: 46 FMI: Oncoming ratio test (during shift), 4 to 6
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 4?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: 53 FMI: Oncoming ratio test (during shift), 5 to 3
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 5?3 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...
