Home >> Jaguar >> 2013 >> XKR-S 2D Convertible >> Repair and Diagnosis >> Quick Lookups >> DTC Index >> Diagnostic Trouble Code Index DTC: Headlamp Control Module A (HCM) -- XK/X150 >> Diagnostic Trouble Code Index DTC: Headlamp Control Module A (HCM) >> Description And Operation >> Headlamp Control Module [HCM] >> DTC U0121-86: Lost communication with Anti-lock Brake System (ABS) Control Module - Signal invalid >> Possible Causes