AC Problem with my ‘13 450h
Next morning it was 95 when I left my house and I turned it on and was coming out regular air and not cold for a bit then started coming out cold for a couple minutes but then completely stopped.
I opened my hood and I noticed my AC Compressor kept short cycling, turning on and off, I have a video of it
After I went home I left the car under my carport and after a couple hours when it cooled down at around 8 or 9pm the ac worked again.
Now today , the ac only barely works if the fan setting is set less than half way, it blows cold but sometimes it still won’t work it just keeps short cycling. I hope someone can help me with this issue since I’m not sure if it’s an expensive fix or an easy fix. One thing I also noticed about this is that the AC Compressor doesn't have a Clutch, it just relies on my high voltage hybrid battery.
► HERE is the Lexus TSB for the HVAC Servo Motor Malfunction problem.
A Lexus service department can flash reprogram the air conditioning amplifier assembly, which often fixes the problem. But it should be noted that the air conditioning amplifier flash reprogram is only performed ONE TIME if the air conditioning amplifier has NOT been flash reprogrammed previously.
The Lexus tech should follow the procedure exactly as outlined in Service Bulletin L-SB-0001-18 'Techstream ECU Flash Reprogramming Procedure' and flash the air conditioning amplifier with the NEW calibration file update.
I hope this helps you!
[edit add] ►See POST #7 in this thread by @jgscott in which he says the problem might be the A/C Compressor Flow Sensor.
Last edited by bclexus; Jul 11, 2024 at 05:23 AM. Reason: orthography
No, you are misunderstanding the 'secondary coverage'.
Some people have received a repair estimate as much as $4,000 to $6,000.
The Lexus Basic Warranty for your 2013 model year Lexus has long since expired. The original TSB states the applicable warranty for this repair is covered under the Lexus Basic Warranty. This warranty was in effect for 48 months or 50,000 miles, whichever occurs first, from the vehicle’s in-service date.
You may be referring to the following 'Customer Support Program' with 'secondary coverage' applicable for 7 years or 125,000 miles from the date of first use, whichever occurs first.
The 'secondary coverage' of 7 years or 125,000 miles from the date of first use, whichever occurs first - has also expired on your 2013 model year Lexus due to age.
Last edited by bclexus; Jul 7, 2024 at 06:30 PM. Reason: orthography
This is what you need to focus on instead of possibly needing to actually replace the servos. Hopefully your problem can be fixed by the 'Techstream ECU Flash Reprogramming Procedure'.
You'll need to talk with your Lexus dealer's service department advisor about it - and now you have the Service Bulletin L-SB-0001-18 about it!

A Lexus service department can flash reprogram the air conditioning amplifier assembly, which often fixes the problem. But it should be noted that the air conditioning amplifier flash reprogram is only performed ONE TIME if the air conditioning amplifier has NOT been flash reprogrammed previously.
The Lexus tech should follow the procedure exactly as outlined in Service Bulletin L-SB-0001-18'Techstream ECU Flash Reprogramming Procedure' and flash the air conditioning amplifier with the NEW calibration file update.
I hope this helps you!
Last edited by bclexus; Jul 7, 2024 at 07:15 PM. Reason: orthography
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@jgscott - Correct, the OP's problem may very well be the A/C Compressor Flow Sensor!
That would be better than a servo motor problem.@Ykeviinn - You should drop by most any auto parts store to have an employee use their diagnostic tool to see if your car has recorded DTC B1479 diagnostic trouble code, which is the code for a failed/failing A/C compressor flow sensor.
If the A/C compressor's flow sensor is found to be the problem, it's an easy fix with a new $40 flow sensor and 45 seconds using a pair of snap ring pliers!

Last edited by bclexus; Jul 11, 2024 at 06:51 AM. Reason: orthography
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