Code result
U3003
Battery Voltage
Moderate severity
What it means
The control module detected battery voltage outside its acceptable operating window. Either too low (drained battery, weak charging) or too high (charging system overvoltage).
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Battery aged or sulfated
highOne of the most commonly reported causes for this code — check this first.
Alternator regulator fault (over- or undervoltage)
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
Related help
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