• Restricted oil pickup
• Mechanical problem in lubrication system
Summary of Fault Correction Possibilities
• Fill the engine with oil.
• Correct the wiring problem.
• Replace the sensor.
• Inspect the oil pump pickup screen.
• Check the mechanical oil pressure.
• Check the bearing clearances, oil pump, and oil pump relief valve.
Guardian_Oil_Temp_Derate
Fault Type:
Horn: Guardian: UFC: Transmission to Helm: Freeze Frame Priority:
Nonsticky Caution Variable 2021‑23 Yes 4
Explanation
Engine Guardian is active due to excessively high or low oil temp. Power will be limited to prevent engine damage.
Possible Causes
• Low engine oil
• High engine coolant temperature
• Sensor wiring problem
• Defective sensor
Summary of Fault Correction Possibilities
• Fill the engine with oil.
• Repair the cooling system.
• Correct the wiring problem.
• Replace the sensor.
Guardian_Overheat
Fault Type:
Horn: Guardian: UFC: Transmission to Helm: Freeze Frame Priority:
Nonsticky Caution Variable 2081‑23 Yes 4
Explanation
Engine Guardian is active due to engine overtemperature. Power will be limited to prevent engine damage.
Possible Causes
• Restricted water flow
• Restricted thermostat
• Blockage in cooling system
• Damaged water pump impeller
Summary of Fault Correction Possibilities
• Flush the cooling system.
• Inspect the thermostat.
• Inspect the cooling system.
• Inspect the water pump impeller.
Fault Codes
90-8M0146617 eng JULY 2018 © 2018 Mercury Marine Page 4A-21