Home >> Land Rover >> 2020 >> Defender 110 First Edition >> Repair and Diagnosis >> General Information >> Specifications Index >> Diagnostic Trouble Code Index DTC: TELEMATIC Control Unit Module (TCU) -- Defender/L663 >> Diagnostic Trouble Code Index - DTC: TELEMATIC Control Unit Module (TCU) (G2400918) >> Description And Operation >> TELEMATIC Control Unit Module (TCU) >> DTC U0028-88: Vehicle communication bus A - Buss off >> Possible Causes