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Home >> Lexus >> 2004 >> IS 300 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 249 (Air Conditioning System (Diagnosis)) >> Circuit Inspection >> DTC B1421 Solar Sensor Circuit >> Circuit Description
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Circuit Description

WARNING: This page is about a different car, the 2003 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.

A photo diode in the solar sensor detects solar radiation and sends signals to the A/C amplifier.

Fig 1: Strength Of Solar Radiation - Resistance Of Photodiode Graph
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DTC - B1421 TROUBLE DETECTION REFERENCE

DTC No. Detection Item Trouble Area
B1421 Open or short in solar sensor circuit. Please note that display of diagnostic trouble code B1421 is not abnormal when the sensor is not receiving solar radiation.
  • Solar sensor.
  • Harness or connector between solar sensor and A/C amplifier.
  • A/C amplifier.
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