OBD
P0691
Fan 1 Control Circuit Low
What it means
P0691 means Fan 1 Control Circuit Low.
Check these first
- A failed fan 1 relay
- A blown fan control fuse
- A short to ground in the fan control wire
- A failed fan motor
- A weak battery
What to do next
- Command fan 1 on with a scan tool
- Check the fan control fuse
- Test the relay and its control wire
- Measure voltage at the fan motor
- Replace the relay, fuse, or fan motor
- Clear the code and retest
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Updated
Generic SAE J2012 definition. Last updated 2026-10-10.