OBD-II code · Powertrain (generic)
P0691 Cooling Fan 1 Control Circuit Low
Cooling Fan 1 Control Circuit Low: the control-circuit voltage is below the expected range. Reduced cooling-fan control can let the engine or A/C condenser overheat.
Is it safe to drive with P0691?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyFan relay defective
- PossibleWiring shorted to ground
- Less likelyConnector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Cooling Fan, Cooling Fan Relay
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.