What does it mean?
U1166 is a Network (CAN bus, module communications) fault code. It indicates: Lost Communications With Memory Seat Module .
Symptoms
- Memory buttons no longer recall seat positions
- Some or all seat adjustment directions inoperative, or the seat working only from certain switches
- Mirrors, steering column or pedals that normally move with the memory function staying put
- Easy entry and exit function no longer working
- A message that the memory function is unavailable
- The seat module missing from the scan tool module list
Likely causes
- Harness under the seat pinched, stretched or cut by the seat rails as the seat is moved
- Connector under the seat kicked loose or left unplugged after cleaning, seat removal or upholstery work
- Liquid spills, snow or salt from shoes corroding the module and its connector
- Blown fuse or a poor ground for the memory seat module
- Open or shorted bus wiring between the seat module and the body control module
- Seat motor or position sensor drawing excessive current so the module protects itself
- Internal failure of the memory seat module
How to fix it
- Move the seat through its full travel while monitoring communication with the scan tool to catch an intermittent break
- Inspect the under-seat harness for pinch points, cut insulation and connectors that are unplugged or full of debris
- Check for corrosion caused by spills and road salt on the module and its pins
- Measure supply voltage and ground at the module under load and check the relevant fuse
- Test the bus wiring between the seat module and the body control module for continuity and shorts
- Check the seat motors and position sensors for a seized motor or a jammed track that overloads the module
- Replace the memory seat module last, then carry out the seat position calibration and store new memory positions