Allison WTEC II Fault Code: 24 PID: SPN: 12 FMI: Sump fluid temperature, cold

Main code 24 indicates the ECU has detected either a high or low fluid temperature in the transmission sump (via the sump temperature sensor in the internal harness). All shifts are inhibited when Code 24 12 is set (only Neutral range operation is allowed). A related code is 33 12 which indicates a temperature reading outside the usable range of the sensor and indicates a probable sensor failure.