2003 Lexus GS 300FACTORY OEM SERVICE PROCEDURE

HVAC DTCS

HVAC DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

DTC Description
B1411/11 Room temperature sensor circuit
B1412/12 Ambient temperature sensor circuit
B1413/13 Evaporator temperature sensor circuit
B1418/18 Exhaust gas sensor circuit
B1421/21 Solar sensor circuit (Passenger Side)
B1422/22 All conditions below are detected for 3 sec. or more
  1. Engine speed: 450 rpm or more
  2. Ratio between engine and compressor rpm deviates 20% or more in comparison to normal operation.
B1423/23 Open in pressure sensor circuit Abnormal refrigerant pressure [below 196 kPa (2.0 kgf/cm2 , 28 psi) over 3,140 kPa (32.0 kgf/cm2 , 455 psi)]
B1424/24 Solar sensor circuit (Driver Side)
B1431/31 Air mix damper position sensor circuit (Passenger Side)
B1432/32 Air inlet damper position sensor circuit
B1433/33 Air outlet damper position sensor circuit
B1436/36 Air mix damper position sensor circuit (Driver Side)
B1441/41 Air mix damper control servomotor circuit (Passenger side)
B1442/42 Air inlet damper control servomotor
B1443/43 Air outlet damper control servomotor circuit
B1446/46 Air mix damper control servomotor circuit (Driver side)
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.