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


U1146 Description


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.