Caterpillar Fault Code
Free · no signupSPN 168 FMI 2
Lights flickering; Radio resetting; Random "ghost" codes across different systems; Hard starting.
System
Not specified
Symptom
Lights flickering; Radio resetting; Random "ghost" codes across different systems; Hard starting.
Diagnosis & fix steps
System Voltage Intermittent
LOGIC: Battery voltage is "noisy" or dropping below 9V momentarily.
ACTION: Perform a load test on batteries. Check the "Clean Machine Ground" (usually a small wire directly to the battery negative). Inspect alternator belt tension.
FIX: Clean/tighten battery terminals; replace batteries or alternator.
Red Seal field insights
On CAT machines, 90% of intermittent electrical issues are caused by a loose or corroded main ground stud on the frame. Clean it down to shiny metal.
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