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Home >> Jeep >> 2014 >> Compass Limited, AWD, Automatic Trans >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 121 (Transmission Control Module (TCM) - Electrical Diagnostics) >> DTC Troubleshooting >> U1146-Lost Communication With External Memory >> Theory Of Operation
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Theory Of Operation

WARNING: This page is about a different car, the 2012 Jeep Patriot and 2012 Jeep Compass. However, it is still accessible from the selected car via links, so may be relevant.

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.