Home >> Land Rover >> 2021 >> Defender 90 X >> Repair and Diagnosis (Single Page) >> Quick Lookups >> Common Specs & Procedures >> Diagnostic Trouble Code Index DTC: Gateway Module (GWM) -- Defender/L663 >> Diagnostic Trouble Code Index: Gateway Module (GWM) (G2801686) >> Description And Operation >> Gateway Module (GWM) >> DTC U0037-88: Vehicle Communication Bus B - Bus off >> Possible Causes