Lexus IS Solar Sensor Error

Hey, I have an IS too, although I can't remember the year. I had a similar heating issue not too long ago. Low heating output is the worst. I remember the mechanic mentioning something about a sensor fault related to the heating system. I'm no expert, but I think the solar sensor tells the system about the sun's intensity, so the system needs to adjust things like the AC and stuff to compensate. Did you try calibrating the sensor? Does the diagnostic tool give you any specific error codes?

Thanks for the quick reply! I haven't tried calibrating the solar sensor yet. I'm not even sure how to do that, to be honest. I have a basic OBD2 scanner, but it doesn't give me much beyond the generic error code. I'll have to see if I can find a procedure for calibrating it. When you say 'sensor fault,' do you remember if it was specifically the solar sensor, or a different temperature sensor in the system?

Okay, so I vaguely remember more details. It was a temperature sensor, BUT the mechanic told me that the Lexus system uses info from multiple sensors to control the cabin temperature. He called it a 'solar sensor' because it factors in sunlight, but it could be multiple things. Honestly, I'd recommend taking it to a good workshop with diagnostic tools that can read the Lexus-specific codes. They'll pinpoint the problem and calibrate the sensor. I took mine in and they fixed my issue for a reasonable price. Definitely worth the money instead of blindly replacing parts.

Thanks so much for the advice! I think you're right. I'll book an appointment with a workshop that specializes in Lexus vehicles and has the right diagnostic equipment. I've gotten a quote for 95€, which sounds reasonable. Hopefully, they can sort it out quickly. I'll post the resolution once I have it.