Eaton Gen 2 (AutoShift) Fault Code: 41 PID: SID 56 FMI: 7 Range Failed to Engage

Overview:
Fault Code 41 indicates the transmission is unable to complete a shift across the range. The range is either stuck in HI or LO, or cannot complete engagement into HI or LO.

Detection:
The transmission attempts the same range shift 5 consecutive times and determines the shift cannot be completed based on the speeds across the back box.

Fallback:
This fault causes a 5-speed fallback and the transmission stays in either LO range or HI range. When the vehicle comes to a stop, an attempt to shift into LO range is made.

Possible Causes:
1) Low air pressure
2) Contaminated air supply
3) Air leak
4) Range valve
5) Range Synchronizer
6) Range Actuator, Cylinder, Piston or Yoke

Shop Talk:
Operate vehicle and perform several range up shifts and down shifts. The failure is detected after 5 consecutive attempts to complete the same type of range shift. Several shifts (10 or more) may be necessary before the controller confirms the failure.