P0691
Fan 1 Control Circuit Low
P0691 is an OBD-II diagnostic trouble code meaning: Fan 1 Control Circuit Low. Common causes: fan control wire short circuit to ground, cooling fan 1 relay malfunction. Estimated repair cost: $11–222.
Symptoms
- The Check Engine light comes on
- Cooling fan does not turn on or runs constantly
- Engine overheating, especially in traffic jams
- Turning on the overheat alarm on the dashboard
- Reduced air conditioner efficiency (if the fan is shared)
Causes
- Fan control wire short circuit to ground
- Cooling Fan 1 Relay Malfunction
- Broken or damaged control circuit wiring
- Cooling fan motor malfunction
- Internal ECU fault
How to Fix
- Read OBD-II codes and record all data
- Check the operation of the cooling fan visually and using a scanner
- Measure the voltage in the fan control circuit 1
- Check the fan relay and its connector
- Check the fan motor for operation (direct power supply)
- If the external circuit is working properly - ECU diagnostics
Related codes
Error P0691 by Vehicle Brand
FAQ
What does the P0691 code mean?
P0691 is an OBD-II diagnostic trouble code that indicates: Fan 1 Control Circuit Low
What causes a P0691 error code?
The most common causes of P0691 include: Fan control wire short circuit to ground; Cooling Fan 1 Relay Malfunction; Broken or damaged control circuit wiring; Cooling fan motor malfunction.
How do I fix a P0691 diagnostic trouble code?
To fix P0691: Read OBD-II codes and record all data. Check the operation of the cooling fan visually and using a scanner. Measure the voltage in the fan control circuit 1. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P0691?
Do not drive — repair immediately
How much does it cost to fix P0691?
The estimated repair cost for P0691 is $11–222. Actual cost depends on your vehicle, location, and labor rates.
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