Lost Communication With Shifter
Table of contents
U12AA Possible Causes
- Faulty SBW Shifter Control Module
- SBW Shifter Control Module harness is open or shorted
- SBW Shifter Control Module circuit poor electrical connection
- Faulty Transmission Control Module (TCM)
How do I fix code U12AA?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the U12AA code
The cost of diagnosing the U12AA code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
- Engine Light ON (or Service Engine Soon Warning Light)
The Controller Area Network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using F-CAN A and B signal lines. If the Transmission Control Module (TCM) cannot receive the signal sent from the SBW Shifter Control Module for a specified time, or if the received signal is abnormal for a specified duration, the TCM detects a malfunction and stores a Diagnostic Trouble Code (DTC).