Overview:
The Fuller Advantage transmission may be equipped with an analog shift control device. The Transmission Electronic Control Unit (TECU) supplies the analog Shift Control Device a 5-volt reference through OEM wiring. This voltage is reduced by resistive ladder circuitry in the shift device, based on the position the driver selects. The return voltage to the TECU indicates the position of the Shift Lever. Fault Code 83 indicates the TECU did not identify a Shift Lever position.

Detection:
The TECU monitors Shift Lever position by supplying voltage to the Shift Lever and measuring the returned voltage. When the return voltage received by the TECU does not match any known shift mode this fault code sets Active.

Conditions to Set Fault Code Active:
FMI 14 – Special Instructions: Selected lever position is invalid for 0.5 seconds or longer.

Fallback:
FMI 14
• “F” flashes in gear display.
• Service light flashes (if equipped).
• Transmission may not engage a gear from neutral.
• Transmission enters downshift-only mode.

Conditions to Set Fault Code Inactive:
FMI 14: TECU recognizes a valid Shift Lever position from the Shift Lever after 0.2 seconds.

Possible Causes:
FMI 14
1) Vehicle Analog Shift Device
– Internal failure
– Lever positioned between two modes
2) Eaton Cobra Shift Lever
– Internal failure
– Lever positioned between two modes