DTC U2138-00: Communication Error With Rear Side Radar Sensor (LH) [Vehicle Control Module]: Outline

DTC U2138:00 [VEHICLE CONTROL MODULE] DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	Communication error with rear side radar sensor (LH)
Detection condition	The vehicle control module (VCM) detects that the rear side radar sensor (RH) cannot receive the CAN signal from the rear side radar sensor (LH) for 15 s.
Fail-safe	(See DTC TABLE [VEHICLE CONTROL MODULE (US)] .)
Possible cause	Rear side radar sensor (LH) connector or terminal malfunction Short to ground or open circuit in rear side radar sensor (LH) power supply circuit Rear side radar sensor (LH) ground circuit malfunction Rear side radar sensor (RH) connector or terminal malfunction Short to ground in local CAN circuit Short to power supply in local CAN circuit Open circuit in local CAN circuit Rear side radar sensor (LH) malfunction Rear side radar sensor (RH) malfunction Vehicle control module (VCM) malfunction (built into body control module (BCM))
Courtesy of MAZDA MOTORS CORP.