DTC U0422-86: Error Signal Received From BCM [Electrical Supply Unit (ESU)]: Notes

DTC U0422-86: (ELECTRICAL SUPPLY UNIT) DETECTION CONDITION AND POSSIBLE CAUSE

Description	Error signal received from BCM
Detection condition	Any of the following conditions is met with the ignition switched ON (engine off or on): The electrical supply unit (ESU) received a headlight LO on request signal error signal from the BCM for 2 s or more. The electrical supply unit (ESU) received a headlight HI on request signal error signal from the BCM for 2 s or more. The electrical supply unit (ESU) detected a mismatch in the following signal combinations received from the BCM for 2 s or more. Headlight variation information signal Headlight LO on request signal The electrical supply unit (ESU) detected a mismatch in the following signal combinations received from the BCM for 2 s or more. Headlight variation information signal Headlight HI on request signal
Fail-safe	Not applicable
Possible cause	DTCs are stored in the BCM. 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 BCM malfunction Electrical supply unit (ESU) malfunction
Courtesy of MAZDA MOTORS CORP.