John Deere Fault Code
Free · no signupSPN 1638 FMI 0
Overheating Alarm.
System
Not specified
Symptom
Overheating Alarm.
Diagnosis & fix steps
LOGIC: Hydraulic oil temperature high.
ACTION: Clean hydraulic cooler with low-pressure air; check thermal bypass valve operation.
Red Seal field insights
On John Deere forestry equipment, wood debris often packs in between the radiator and oil cooler. You have to split the coolers to see the blockage.
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