P0666 OBD II Trouble Code PCM/ECM/TCM Internal Temperature Sensor Circuit
How to easily troubleshoot and repair, and causes of a P0666 trouble code which indicates a detected internal temp sensor circuit fault in a PCM, ECM, or TCM module.
Symptoms of P0666 OBD II Trouble Code
- Engine will not start
- Engine may stall
- Improper shifting
- Transmission warning lamp illuminated
- Check engine light illuminated
Common Causes of P0666 OBD II Trouble Code
- Corroded or damaged connector
- Loose or defective control module ground strap
- Faulty or damaged wiring
- Defective PCM, ECM, or TCM
Severity of P0666 OBD II Trouble Code
The severity of this code can vary tremendously from just an illuminated check engine light or a transmission warning lamp on a vehicle that starts and runs to an automobile that will stall or not start at all. The code can be serious depending on the specific nature of the problem.