DTC U0140-00: Communication Error With BCM [Electrical Supply Unit (ESU)]: Notes

DTC U0140-00: (ELECTRICAL SUPPLY UNIT) DETECTION CONDITION AND POSSIBLE CAUSE

Description	Communication error with BCM
Detection condition	Electrical supply unit (ESU) could not receive the CAN signal from the BCM for 2 s or more with the ignition switched ON (engine off or on).
Fail-safe	Exterior lighting system  When the ignition is switched ON (engine off or on), the headlights LO, TNS (parking lights), and panel light turn on and other exterior light controls are stopped. Interior light control system  Turn the interior light off when the room light switch is in the DOOR position.
Possible cause	BCM connector or terminal malfunction Electrical supply unit (ESU) connector or terminal malfunction Short to ground in wiring harness between BCM terminal 2Y and electrical supply unit (ESU) terminal 2I Short to power supply in wiring harness between BCM terminal 2Y and electrical supply unit (ESU) terminal 2I Open circuit in wiring harness between BCM terminal 2Y and electrical supply unit (ESU) terminal 2I BCM malfunction Electrical supply unit (ESU) malfunction
Courtesy of MAZDA MOTORS CORP.