P0A3B
Generator A Over Temperature
What it means
P0A3B means Generator A Over Temperature.
Check these first
- A failing generator A bearing or internal fault
- Low or degraded generator coolant flow
- A failed generator temperature sensor
- Overloading from extended high-load operation
What to do next
- Check the generator coolant level and flow
- Compare the generator A temperature reading against a known-good value
- Inspect the generator cooling passages for blockage
- Check for abnormal noise or drag from generator A
- Replace the generator or temperature sensor after testing
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-08-30.