Allison
Allison WTEC II Fault Code: 54 PID: SPN: 10 FMI: Oncoming ratio test (after shift), 1 to L
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 1?L 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: 12 FMI: Oncoming ratio test (after shift), 1 to 2
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 1?2 upshift ? incorrect calibration, wide ratio vs. close ratio 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...
Allison WTEC II Fault Code: 54 PID: SPN: 17 FMI: Oncoming ratio test (after shift), 1 to R
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 1?R 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: 21 FMI: Oncoming ratio test (after shift), 2 to 1
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 2?1 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: 23 FMI: Oncoming ratio test (after shift), 2 to 3
Posted by PerDiezel Solutions on
Main code 54 indicates a failed oncoming ratio test. 2?3 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...
