U1146 Code: Meaning, Causes, and Symptoms | OBD2 Codes
U1146 – Lost Communication With External Memory
U1146 Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
U1146 Possible Causes
Faulty Transmission Control Module (TCM),Transmission Control Module (TCM) harness is open or shorted,Transmission Control Module (TCM) circuit poor electrical connection
The first time the vehicle is started, the Transmission Control Module (TCM) receives hydraulic calibration data from an external EEPROM (located in the transmission) and stores this information in the EEPROM of the TCM. If the TCM can not read the external EEPROM in the transmission this DTC will set. It takes two consecutive failures to turn on the MIL.