P0669 Powertrain/Engine/Transmission Control Module PCM/ECM/TCM Internal Temperature Sensor "A" Circuit High
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P0669 – OBD-II Trouble Code Technical Description
Trouble code P0669 indicates that the powertrain control module (PCM), engine control module (ECM), or transmission control module (TCM) internal temperature sensor circuit voltage is too high (compared to the manufacturer's specification).
What does the fault code mean P0669?
Trouble code P0669 indicates that the engine control module (ECM), transmission control module (TCM), or powertrain control module (PCM) internal temperature sensor circuit voltage is too high. This means that the signal coming from the temperature sensor exceeds the normal values set by the manufacturer. This usually indicates a problem with the engine or transmission cooling system. Code P0669 may cause the Check Engine Light to appear on your vehicle's dashboard and requires further diagnosis and repair of the problem. Errors may also appear along with this error: P0666, P0667 и P0668.
Possible reasons
Possible Causes of DTC P0669
- Defective temperature sensor: The temperature sensor may be damaged or failed, causing the temperature to be read incorrectly and causing the P0669 code to occur.
- Wiring and connections: The wiring connecting the temperature sensor to the control module (ECM, TCM, or PCM) may be damaged, broken, or poorly connected, resulting in high voltage in the circuit.
- Cooling system problems: Improper operation of the engine or transmission cooling system can cause the temperature to rise, resulting in a high voltage in the temperature sensor circuit and a P0669 code.
- Control module malfunction: The control module itself (ECM, TCM or PCM) may be faulty, causing the temperature sensor data to not be processed correctly and an error to appear.
- Grounding problems: Insufficient grounding of the temperature sensor can also cause high circuit voltage and P0669.
These are just a few possible causes of the P0669 code, and it is recommended that you have your vehicle diagnosed using specialized tools and equipment to determine the exact cause.
What are the symptoms of a fault code? P0669?
Symptoms associated with DTC P0669 may include the following:
- Check Engine Light: The appearance of the Check Engine light on your car's dashboard is one of the most common signs of a problem.
- Loss of power: Engine performance may be reduced, especially when accelerating or operating at low speeds. This may occur due to malfunctioning engine control based on incorrect temperature data.
- Unstable engine performance: Rough engine operation, shaking when idling, or unstable rpm may be noticed.
- Increased fuel consumption: Incorrect operation of the engine management system due to incorrect temperature data can lead to increased fuel consumption.
- Gearbox behavior: If the error code is related to the transmission control module (TCM), there may be problems with shifting, such as hesitation, jerking, or unusual noises.
These symptoms may occur to varying degrees depending on the specific problem and the type of vehicle.
How to diagnose a fault code P0669?
The following steps are recommended to diagnose DTC P0669:
- Check the Check Engine Light: If the Check Engine Light illuminates on your vehicle's dashboard, it may be a sign of P0669. However, if the light does not come on, this does not rule out the problem, since not all cars can instantly activate the light when an error is detected.
- Use a diagnostic scanner: Connect the diagnostic scanner to the OBD-II port of your car. The scanner will read trouble codes, including P0669, and provide information about other parameters and sensors that can help with diagnosis.
- Explore additional error codes: Sometimes the P0669 code may be accompanied by other error codes that may provide more information about the problem. Check any other codes that may be registered in the system.
- Check wiring and connections: Check the wiring connecting the temperature sensor to the control module (ECM, TCM or PCM) for damage, corrosion or breaks. Make sure all connections are secure and free of oxidation.
- Check the temperature sensor: Check the condition and functionality of the temperature sensor. You may need to check the sensor resistance at different temperatures using a multimeter.
- Additional tests and checks: Depending on the specific vehicle type and engine management system, additional tests may include cooling system performance, oil pressure, and other parameters that may be related to engine or transmission temperature.
- Consult with a professional: If you are unsure of your skills or experience in diagnosing automotive systems, it is recommended that you contact a qualified auto mechanic or service center for a more detailed diagnosis and resolution of the problem.
Diagnostic errors
When diagnosing DTC P0669, the following errors may occur:
- Ignoring additional error codes: Trouble P0669 may be accompanied by other error codes that may provide additional information about the problem. The error may be caused not only by high voltage in the temperature sensor circuit, but also by other factors that may be reflected in additional codes.
- Insufficient diagnostics of wiring and connections: The wiring connecting the temperature sensor to the control module may be damaged or have poor contact. Failure to sufficiently check this wiring may result in the cause of the error being incorrectly determined.
- Replacing the sensor without first checking: Replacing the temperature sensor without first diagnosing it may not be effective if the cause of the problem lies elsewhere, such as in the wiring or control module.
- Insufficient cooling system check: High voltage in the temperature sensor circuit may be due to problems in the engine or transmission cooling system. Failure to properly diagnose this system may result in the problem being missed.
- Skip control module check: The control module (ECM, TCM or PCM) can also be the cause of P0669. Skipping diagnostics on this component may result in insufficient resolution of the problem.
To avoid these errors, it is important to conduct a comprehensive diagnosis, including checking all possible causes of the P0669 code, and contact qualified technicians if necessary.
How serious is the fault code? P0669?
Trouble code P0669 should be considered serious as it indicates potential problems with the internal temperature of the engine or transmission. Possible consequences of this error may be as follows:
- Loss of power: Inaccurate temperature data may result in incorrect engine management system settings, which may cause loss of power.
- Increased fuel consumption: Incorrect fuel and ignition management due to incorrect temperature data may result in increased fuel consumption.
- Engine damage: If the engine is not cool enough or overheated, serious problems may occur such as damage to the cylinder head, cylinder head gaskets, piston rings, etc.
- Transmission damage: If the problem also affects transmission control, incorrect temperature data may cause incorrect gear shifting and even damage to the transmission.
While the P0669 code may be considered serious, it is important to consider that in some cases it may be caused by a temporary glitch or a minor defect that can be easily fixed. However, if the P0669 code persists or occurs again after correction, it is recommended that you contact a professional for more detailed diagnosis and repair.
What repair will help eliminate the code? P0669?
Troubleshooting the P0669 trouble code may require several possible actions depending on the specific cause of the problem. Here are some typical repair methods:
- Replacing the temperature sensor: If the error is caused by a faulty temperature sensor, it may need to be replaced. It is recommended to use original spare parts or high-quality analogues to avoid further problems.
- Checking and repairing wiring: If the cause of the error is due to damage or broken wiring, it is necessary to check and, if necessary, repair the wiring, ensuring a reliable connection between the temperature sensor and the control module.
- Diagnostics and replacement of the control module: If all system components are working properly but P0669 still occurs, the cause may be a faulty control module (ECM, TCM or PCM). In this case, diagnostics may be required to determine the malfunction and replacement or repair of the control module.
- Checking and fixing cooling system problems: If the cause of the error is problems with the temperature of the engine or transmission, additional diagnostics of the cooling system must be carried out. This may include checking for coolant, thermostat condition, leaks, or pump problems.
- Programming and software updates: In some cases, the cause of the P0669 code may be problems with the control module software. Updating or reprogramming the software may help resolve the problem.
It is important to note that it is recommended that you contact a qualified auto mechanic or service center to accurately determine and correct the cause of the P0669 code, especially if you do not have experience working with automotive systems. Improper repairs or diagnosis may result in additional problems or damage.
P0669 – Brand-specific information
Trouble code P0669 can be found on different brands of cars, and its interpretation may vary slightly depending on the specific manufacturer, a list of several popular brands of cars with brief explanations of the P0669 error code:
- Toyota / Lexus: Engine temperature sensor circuit voltage is too high.
- Honda/Acura: PCM/ECM/TCM Internal Temperature Sensor “A” Circuit: Signal High.
- Ford: Engine or transmission temperature sensor circuit voltage is too high.
- Chevrolet / GMC: High voltage in the engine temperature sensor circuit.
- BMW/Mini: PCM/ECM/TCM Internal Temperature Sensor “A” Circuit: Signal High.
- Mercedes-Benz: Engine or transmission temperature sensor circuit voltage is too high.
- Volkswagen/Audi: High voltage in the engine temperature sensor circuit.
- Nissan/Infiniti: PCM/ECM/TCM Internal Temperature Sensor “A” Circuit: Signal High.
This is just a small list of examples, and each car brand may have its own context for the P0669 code. For more accurate information, it is recommended that you consult the specific documentation, service manuals, or qualified personnel for your specific vehicle make and model.
