Allison WTEC II Fault Code: 61 PID: SPN: 00 FMI: Retarder oil temperature sensor, failed low

Posted by PerDiezel Solutions on January 10, 2026

Main code 61 indicates the ECU has detected a hot fluid condition in the output retarder.

Possible causes (but not all causes) for hot fluid are:
1. Prolonged retarder use.
2. Low fluid level.
3. High fluid level.
4. A retarder apply system that allows the throttle and retarder to be applied simultaneously.
5. Cooler inadequately sized for retarder.

Allison WTEC II Fault Code: 57 PID: SPN: 99 FMI: Range verification C3PS test, N1 or N4

Allison WTEC II Fault Code: 57 PID: SPN: 88 FMI: Range verification C3PS test, N1

Allison WTEC II Fault Code: 57 PID: SPN: 66 FMI: Range verification C3PS test, 6th

Allison WTEC II Fault Code: 57 PID: SPN: 44 FMI: Range verification C3PS test, 4th

Allison WTEC II Fault Code: 57 PID: SPN: 22 FMI: Range verification C3PS test, 2nd

Allison WTEC II Fault Code: 57 PID: SPN: 11 FMI: Range verification C3PS test, 1st

WARNING!