DTC P189F-00: Electrical Supply Unit (ESU) Power Supply - Low Input: Outline

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC P189F:00 (PCM, SKYACTIV-G) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	Electrical supply unit (ESU) power supply: Low input
Detection condition	The PCM detects a short to ground or open circuit in the electrical supply unit (ESU) power supply circuit.
Fail-safe	Inhibits the i-ACTIV AWD control.
Possible cause	Electrical supply unit (ESU) connector or terminals malfunction Short to ground or open circuit in electrical supply unit (ESU) power supply circuit Electrical supply unit (ESU) malfunction PCM malfunction
Courtesy of MAZDA MOTORS CORP.