P0691

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

1. Read OBD-II codes and record all data
2. Check the operation of the cooling fan visually and using a scanner
3. Measure the voltage in the fan control circuit 1
4. Check the fan relay and its connector
5. Check the fan motor for operation (direct power supply)
6. If the external circuit is working properly - ECU diagnostics

Related codes

Error P0691 by Vehicle Brand