Explanation
The secondary encoder in the shift demand sensor does not appear to be working properly; the PCM received a signal that is
below the valid limit.
Possible Causes
• Wiring problem
• Defective sensor
Summary of Fault Correction Possibilities
• Correct the wiring problem.
• Replace the sensor.
ShiftPos_RangeHigh
Fault Type:
Horn: Guardian: UFC: Transmission to Helm: Freeze Frame Priority:
Sticky Critical 50% 1021‑24 Yes 2
Explanation
The primary shift position encoder in the shift actuator does not appear to be working properly; the PCM received a signal that
is above the valid limit. Power is limited to prevent engine damage.
Possible Causes
• Wiring problem
• Mechanical issue in gearcase
• Failed shift actuator
Summary of Fault Correction Possibilities
• Inspect the wiring to the shift actuator, repair as needed.
• Inspect the gearcase for proper shifting.
• Replace the shift actuator.
ShiftPos2_RangeHigh
Fault Type:
Horn: Guardian: UFC: Transmission to Helm: Freeze Frame Priority:
Sticky Critical 50% 1023‑24 Yes 2
Explanation
The secondary shift position encoder in the shift actuator does not appear to be working properly; the PCM received a signal
that is above the valid limit. Power is limited to prevent engine damage.
Possible Causes
• Wiring problem
• Failed shift actuator
Summary of Fault Correction Possibilities
• Inspect the wiring to the shift actuator, repair as needed.
• Replace the shift actuator.
ShiftPos_RangeLow
Fault Type:
Horn: Guardian: UFC: Transmission to Helm: Freeze Frame Priority:
Sticky Critical 50% 1021‑25 Yes 2
Explanation
The primary shift position encoder in the shift actuator does not appear to be working properly; the PCM received a signal that
is below the valid limit. Power is limited to prevent engine damage.
Fault Codes
90-8M0146617 eng JULY 2018 © 2018 Mercury Marine Page 4A-37