What is the P0666 fault code and description? What is the description for the error code P0666 PCM/ECM/TCM Internal Temperature Sensor Circuit? How can I fix the P0666 fault code What are the symptoms, causes, and solutions for the P0666 fault code?
What is the P0666 Fault code? What does it signify?
The internal temperature sensor circuit has the code P0666. This circuit contains the powertrain control module, engine control module and/or transmission control modules (TCM). Some vehicles don’t include ECM or TCM. These modules are combined and called PCM.
The internal temperature sensor monitors the temperature of control modules. The fault code P0666 is set when the PCM/ECM/TCM detects an error in the internal temperature sensor circuit. This will cause the engine and transmission fault lamps to activate. The control module will shut down in order to prevent damage in the event of an overtemperature.
Vehicles susceptible to the P0666 fault code include but aren’t limited to various Nissan, Opel and Ford models as well as Mazda, Honda, Dodge and BMW models.
What is the P0666 Fault Code?
Here are some reasons why P0666 should be set.
- – Corroded and damaged wires or connectors, melting, corroded, corroded and/or damaged. This can cause a short circuit in one of the control module’s control modules.
- – The engine and transmission are overheated (this is both cause & effect).
- – Defective control module (PCM/ECM/TCM)
A malfunctioning radiator or transmission cooler can cause excessive heat, clogged transmission line, and P0666. In this instance, the fault codes are also set.
What are the P0666 Malfunction Code Symptoms
You may experience the following symptoms if your vehicle has the code P0666:
- – Illumination and control of the check engine light
- – The transmission warning light is on
- Engine stalling
- – Engine is not running
- – Faulty gear changes in an automatic transmission
- – Engine overheating
- – Gearbox overheating
How to Fix the P0666 Fault Code
Each control module is equipped with temperature sensors to aid in self-diagnosis, and protection in the event of failure. Sometimes it is easy to find the module in fault mode. Start by checking the power and ground circuits, then compare them to the factory specifications and making any repairs. All codes should be cleared, and the system should then be retested. The module could be defective if the ground and power circuits work properly. You will need to replace the module and reprogram it.
There are several repairs that can resolve the P0666 fault code.
- – Making repairs and testing control module circuits
- Repair of corroded and melted cables and connectors
- – Repair and replacement of ground and power wires
- Repair of malfunctions that lead to engine or transmission overheating
- – Replacing defective control modules (PCM/ECM/TCM))
How Serious Is the P0666 Fault Code
A code P0666 will set the vehicle off. Although it’s rare that the vehicle is able to be driven, the engine will most often stop running. The vehicle will then not start until the problem has been resolved. This is a problem that you should address immediately.
