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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 82 (Heating / Air Conditioning System - Diagnostic Codes (2 Of 3)) >> AIR CONDITIONING SYSTEM (for PHEV Model) >> DTC B3A01-12: A/C Evaporator Front Magnetic Valve Circuit Short to Battery [08/2023 - ] >> Description

DTC B3A01-12: A/C Evaporator Front Magnetic Valve Circuit Short to Battery [08/2023 - ]: Description

WARNING: This page is about a different car, the 2025 Lexus RX 450h+ and 2024 Lexus RX 450h+. However, it is still accessible from the selected car via links, so may be relevant.

The evaporator front magnetic valve (No. 2 magnet valve assembly) is installed to the air conditioning tube and accessory assembly and is open when the ignition switch is turned off. When the ignition switch is turned to ON, the evaporator front magnetic valve (No. 2 magnet valve assembly) opens and closes according to heat pump air conditioning control. When heat pump air conditioning control is performing heating/single battery cooling/gas injection heating, the evaporator front magnetic valve (No. 2 magnet valve assembly) is closed according to signals from the heat pump ECU assembly. When heat pump air conditioning control is performing parallel dehumidification heating, the evaporator front magnetic valve (No. 2 magnet valve assembly) is open.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory DTC Output from Priority Note
B3A01-12 A/C Evaporator Front Magnetic Valve Circuit Short to Battery Diagnosis condition:
  1. Evaporator front magnetic valve (No. 2 magnet valve assembly) operating

Malfunction status:
  1. Short to +B in evaporator front magnetic valve (No. 2 magnet valve assembly) circuit

Detection time:
  1. Continuously for 4 seconds or more
  • Heat pump ECU assembly
  • Harness or connector
Does not come on Memorized Air Conditioner A -