What does it mean?
B2188 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Communication Line (UART Line) Driver's MPCS Unit cannot receive UART messages from Front Passenger's MPCS Unit. .
Symptoms
- Passenger memory seat functions completely inoperative
- Driver memory functions partly working, mirrors or column may recall but not the passenger seat
- Rear wiper stuck on or dead if the wiper definition applies
- Scan tool cannot reach the passenger seat control unit
- Warning message about a seat or comfort system fault
- Code returns immediately after clearing
Likely causes
- Rear wiper switch stuck closed or a grounded select wire in the tailgate loom
- Passenger seat control unit with no power because of a blown fuse or an unplugged connector
- Communication wire between the two seat control units broken, usually under the carpet in the tunnel or the sill
- Connector under the passenger seat loose, damp or corroded after a spill or a leaking seal
- Passenger seat control unit failed internally and no longer transmitting
- Poor ground for either seat control unit
- Damage to the loom from seat rail movement or from items stored under the seat
- Low or unstable system voltage disturbing the serial link
How to fix it
- Confirm the manufacturer definition for this vehicle, the two meanings need different tests
- Check the fuse feeding the passenger seat control unit and measure its supply and ground
- Try to communicate with the passenger unit directly with the scan tool
- Lift the carpet along the tunnel and sill and inspect the communication wire for pinch damage and corrosion
- Reseat both under seat connectors and check for damp and green terminals
- Measure the communication line for continuity between the two units and for shorts to ground and battery
- For the wiper variant, unplug the rear wiper switch and test the select input for a short to ground
- Repair the wiring or replace the faulty unit, then confirm both seats store and recall their memory positions