B1421
Book Code B1421 Inspection
Automotive Climate Control
Low / Normal Under Shade
⚠️ Normal in Shade
Code B1421 - Solar Sensor Circuit (Passenger Side) - Toyota / Lexus
Code B1421 in Toyota and Lexus vehicles indicates that the passenger-side solar sensor is not detecting direct sunlight or has a circuit abnormality.
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Critical Advice for Drivers (Save Your Money):
Crucial Notice: If you scan the car inside an indoor workshop, at night, or under shade, code B1421 is 100% normal and NOT a defect! The solar sensor simply requires direct sunlight or an inspection light to clear.
Safe to Drive? ✅ Yes, Safe
Estimated Repair Cost 0 - 250 SAR
Common Makes Toyota, Lexus
System Category sensor
Symptoms of Trouble Code B1421:
- ⚠️ Minor inconsistency in blower fan speed when in AUTO climate mode
- ⚠️ Code appears on OBD-II diagnostic scanner without triggering Check Engine light
- ⚠️ AC cools normally under manual control settings
Common Causes Behind Code B1421:
- 🔍 Scanning the vehicle indoors or under shade (95% of cases)
- 🔍 Dust accumulation or dashboard mat blocking the sensor lens
- 🔍 Sensor connector unplugged during dashboard upholstery or Android screen installation
- 🔍 Actual photovoltaic sensor cell degradation (rare)
Diagnostic Procedure Recommended by Auto Save Technicians:
- 1 Move vehicle into direct sunlight or shine a high-lumen flashlight directly over the dashboard sensor
- 2 Clear diagnostic trouble codes with scanner and re-scan climate control unit
- 3 If code clears, the sensor is completely healthy and requires zero repair
- 4 If code persists in direct sunlight, inspect the harness connector under the dashboard
Specialist Recommendation:
Request Parts & Repair Quote
Do not pay to replace the sensor before testing the car in broad daylight!
Associated Components: Solar Sensor Photodiode HVAC Wiring Harness
Frequently Asked Questions: Code B1421
Does code B1421 cause the AC to blow warm air?
No, code B1421 only relates to sunlight intensity measurement and never affects freon pressure or compressor function.
Where is the B1421 sensor located in Toyota Camry and Land Cruiser?
It is located on top of the dashboard near the front windshield on the passenger side, looking like a small dark coin-sized dome.