What is P0691 fault code? What’s the reason for the Cooling Fan 1 Control Circuit Low error code How do you fix the P0691 fault code What are the causes and symptoms of the P0691 error code?
What is the P0691? What is Fault Code? What does it signify?
If the powertrain control module, PCM detects a low voltage signal in an electric cooling fan control circuit, a code P0691 will be generated. Some vehicles may have two cooling fans. The problem is due to the cooling fan number 1.
Motor fans equipped with electric motors cool the radiator of vehicles. The PCM controls the temperature of the coolant temperature sensor (ECT) to turn these engines on or off. The PCM turns the fans on when the ECT reaches a predetermined temperature. When the ECT reaches a normal temperature, the PCM switches off the fans.
The PCM turns the fans on by sending ground signals to the cooling fan relay. The voltage signal will be close to the battery voltage when it is off. The voltage signal should be close zero when the relay is turned on and grounded. The PCM will set the P0691 error code if it detects a low voltage signal (10% lower than manufacturer specifications) when the relay switch is turned on.
Vehicles susceptible to the P0691 fault code include but aren’t limited to various models of Volkswagen and Ford, Opel Audi or Saab, Opel Opel Audi, Opel Opel Peugeot, Opel and Skoda.
What is the P0691 Fault Code?
Below are some reasons to set fault code P0691:
- – Defective cooling fan relay 1
- – Defective cooling fan motor 1
- – Short-circuited, damaged, melted or broken cables
- – Corroded and/or loose electrical connectors
- – 1 blown cooling fan fuse
- – Failure of cooling fan control module (if applicable).
- – Defective engine coolant temperature sensor
- – The PCM has become faulty or requires reprogramming
What are the Symptoms of Malfunction Code P0691?
You may experience the following symptoms if your vehicle has the code P0691:
- – Illumination and control of the check engine light
- – Not working cooling fan
- – Engine overheating
- Air conditioner not working correctly
- – Reduced engine performance
How do I fix the P0691 fault code?
When dealing with problems in electrical circuits, it is important to test the battery voltage. With the engine running, the battery voltage should be approximately 12.6V.
Bloated cooling fan fuse is the most common reason for this fault code. It is important to locate the fuse and inspect it visually before removing it. The correct amperage fuse should be used to replace the fuse if it blows. If the fuse blows again after you have installed the new fuse, it is likely that there is a short circuit between the relay and the fuse. The cooling fan motor may be defective if the fuse blows before the engine reaches operating temperature. If the engine is not running and the ignition switch is off, turn the fan blades manually. The fan motor must be replaced if the blades do not rotate freely.
If the fuse works, the problem is probably the cooling fan relay. There may be one relay on some vehicles, while others have two. Look at the diagram on top of the fuse box to locate the relay and fuses. You can refer to the vehicle manual for a diagram if you don’t have one. The majority of applications use a 5-pin relay. These pins can be identified by the numbers 85, 86 or 87a, and 30 respectively. A multimeter can be used to verify the reliability of the relay. It is easiest to replace the relay with one that is identical. If the problem persists, replace the relay with another one. It is important to be cautious when working with moving parts.
Note: It is important to ensure that the relay being replaced is the same. The PCM can be damaged if the relay is not installed correctly. The relays on Nissan vehicles are different, but they look almost identical. Although socket inputs look the same, their characteristics can be different which can cause damage to the PCM.
There are several repairs that can resolve the P0691 fault code.
- Relay cooling fan failure
- – Replacing an exploded fuse
- – Repair of short-circuited, damaged, melted, corroded or broken cables
- – Repair of damaged or rusty electrical connectors
- – Replacement or repair of the cooling fan motor.
- – If applicable, replacing the cooling fan control module.
- – Test the coolant temperature sensor and replace it if it is not up to manufacturer specifications
- – Reprogramming and replacing the PCM
The fan motor can appear to be defective in rare instances, but it is actually fluid leakage from the power steering. The hydraulic pressure of the power steering pump is part of what drives the cooling fan motor. If this happens, it can impact the fan motor’s performance. If this happens, the power steering leak must be fixed or replaced.
How serious is the P0691 fault code?
While the code P0691 does not stop the vehicle starting, it can cause excessive heat to the engine and make the air conditioning not work properly. This code should be fixed as soon possible because of the potential damage to the engine caused by excessive heat.
