This fault code indicates an open circuit in the signal circuit of the pressure/temperature sensor at the Plate Heat Exchanger (PHE) outlet — Atto 3
This fault code indicates an open circuit in the signal circuit of the pressure/temperature sensor at the Plate Heat Exchanger (PHE) outlet.
In the BYD heat pump thermal management system, the Plate Heat Exchanger is the core component for heat exchange between the refrigerant and the motor coolant.
The outlet pressure sensor monitors the refrigerant pressure (or integrated temperature) after heat exchange, providing closed-loop control data for the Electronic Expansion Valve (EXV) and the electric compressor.
An open circuit fault indicates the control unit (air conditioning controller or thermal management module) detects a continuous sensor signal voltage above 4.8V (typically corresponding to an unshunted 5V reference voltage).
Without real-time pressure data, the system triggers thermal management protection mode.
This mode disables the heat pump function, limits motor power output, and in extreme cases, prohibits high-voltage power-up to prevent heat exchanger overpressure damage or abnormal refrigerant circulation.
Intermittent open circuit in plate heat exchanger pressure sensor on Qin Pro DM after wading
Qin EV300: Wiring harness wear caused open circuit after accident repair
False open circuit caused by a loose thermal management controller connector
Cracked internal PCB in sensor body caused open circuit at low temperatures
Hidden open circuit caused by water ingress and corrosion in the adapter plug