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P0691 Fault-Error Code Fan 1 Control Circuit Low Voltage

Updated: Oct 3

What is the P0691 Fault-Error Code ?

 

The P0691 Fault-Error Code indicates a problem with the vehicle's cooling system or fan circuits. This error typically refers to a low voltage or current in the vehicle's fan circuit detected by a sensor. The "Fan 1 Control Circuit Low" error typically indicates a low voltage or current in the control circuit of a cooling fan, commonly referred to as fan 1.

 

What are the symptoms of the P0691 Fault-Error Code ?

 

Symptoms of P0691 Fault-Error Code may include:

 

High Engine Temperature: If the cooling system is affected by a problem with the fan circuit, the vehicle's engine temperature may be higher than normal. This is usually noticed when the thermometer indicates overheating.

 



Malfunction Light On: If the malfunction light (usually the "Check Engine" light) is illuminated on your vehicle's dashboard, it may indicate the presence of the P0691 error code, which indicates that low voltage or current has been detected in the fan circuit.

 

Fans Not Working or Operating Abnormally: A problem with the fan circuit can cause the fans not to work at all or to operate abnormally. Fans should normally operate to reduce engine temperature, so if the fans do not come on or operate at low speed, the cooling system will be affected.

 



Decreased Engine Performance: When the cooling system is not working properly, the performance of the engine can be adversely affected. Performance problems such as decreased engine power or fluctuations can occur.

 

What Could Be the Causes of the P0691 Fault-Error Code ?

 

Possible causes for P0691 Fault-Error Code may include:

 

Connection Problems: There may be corrosion, loose connections, or shorts at the connection points related to the fan circuit or fan control module. These connection problems can cause low voltage or current.

 



Fan Motor Failure: The fan motor may be faulty or overloaded. This may cause low voltage or current in the fan circuit.

 

Fan Control Module Failure: The fan control module used to control the vehicle's cooling system may be faulty. This can reduce the fans' operating level or stop them completely.

 

Sensor Failure: The sensors that control the voltage or current of the fan circuit may be faulty or giving false readings.

 



Electrical Issues: A general problem with the vehicle's electrical system can cause low voltage or current in the fan circuit.

 

Short Circuits in the Fan Circuit: A short circuit in the fan circuit can cause low voltage or current. Short circuits are usually the result of damage or incorrect connections in the electrical wiring.

 

What Steps Should Be Followed to Resolve the P0691 Fault-Error Code ?

 

To resolve the P0691 fault/error code, the following steps can be followed:

 

Checking the Connections: First, check the connection points related to the fan circuit or fan control module. The connections may be corroded, loose or shorted. If any problems are found, the connections should be repaired or replaced.

 



Testing the Fan Motor and Control Module: Using a multimeter or suitable electrical tester, the fan motor and control module should be tested. Questions such as whether the fan motor is operating properly and whether the control module is responding appropriately should be sought.

 

Checking the Sensors: The sensors that control the voltage or current of the fan circuit should be checked. These sensors should be tested to see if they are giving correct readings. If the sensors are faulty, they should be replaced.

 



Electrical Tests: Electrical tests should be performed on the fan circuit. These tests can be performed to verify voltage and current levels in the circuit. Check for shorts or open circuits.

 

Fan Control Module Replacement: If a fault is detected in the fan control module, this module must be replaced. A new control module must be installed accordingly.

 

Fan Motor Replacement: If the fan motor is faulty or performing poorly, this motor should be replaced.

 



General Check and Test: A general check should be made to ensure that all components are properly installed and the fan circuit is operating normally. The vehicle should be subjected to a test drive and the engine temperature and fan operation should be observed.

 


P0691

What Are the Long-Term Effects of the P0691 Fault-Error Code ?

 

Long-term effects of fault/error code P0691 may include:

 

Engine Damage: If the cooling system is affected due to a problem with the fan control circuit, the engine is likely to overheat and become damaged. In the long term, continued overheating can cause permanent damage to the engine and shorten its life.

 



Electrical Issues: Faults or low voltage in the fan control circuit can cause general problems in the vehicle's electrical system. This can affect other electrical components and reduce the vehicle's overall reliability.

 

Costly Repairs: Long-term problems with the fan control circuit can be costly when repeated repairs or constant replacement of components are required. This can increase the maintenance and repair costs of the vehicle.

 



Decreased Engine Performance: When the cooling system is not working properly, engine performance can be adversely affected. Performance problems such as decreased engine power or fluctuations can occur.

 

Safety Risk: A problem with the fan control circuit can cause the motor to suddenly stop or lose power.




 

Loss of Driving Comfort and Efficiency: When the cooling system does not work properly, vehicle driving comfort may decrease and fuel efficiency may be adversely affected.

 

For these reasons, it is important to quickly diagnose and resolve the problem caused by the P0691 fault/error code. For this, it would be best to contact a specialist service or an authorized mechanic .



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