2011 Lexus RX350's AC is NOT blowing cold air. Scanner showed code B1479. It's related to the "A/C Pressure Sensor Switch".

However, some websites said this sensor is built into the AC compressor. Pleas see https://www.clublexus.com/forums/rx-3rd-gen-2010-2015/824215-rx350-2010-2011-air-conditioning-dtc-b1479-cheap-solution.html

However, I found this on Lexus's part website: https://parts.lexus.com/t/Lexus_2011_RX-350-VIN-starts-with-2/SENSOR--AIR-CONDITIONER-PRESSURE.html

So who is correct here? Also, please see the following picture, is the red arrow pointing to the same sensor?

enter image description here

1 Answer 1


Your Lexus may be using two sensors, one for monitoring pressures and another for monitoring refrigerant flow. The compressor has a replaceable flow sensor (without removing refrigerant) on the compressor, using a circlip to hold it in place. The error code B1479 relates to this sensor on the compressor. The image with red arrow is most likely the pressure sensor monitoring high side pressures. The pressure sensor protects the compressor from self destruction by sending pressure related signals to the ecm; if pressures are too high or below a specified amount (from service manuals), like a leak or crash resulting in rupturing any ac part that results in releasing refrigerant, this sensor informs the ecm. The ecm disables power to the compressor clutch until repairs are made. There's a trick one video shows of a mechanic using a magnet on an extendable wand to place it above the compressor flow sensor; with engnine idling and ac turned on but compressor not running, the flow sensor was tricked into sending signals to the ecm triggering ac compressor operation. You might be able to do this, however beware of other issues. Loss of refrigerant is a main cause of inoperative ac systems. If incorrect diagnosing occurs, you may be knee deep in ac repairs. Ac repairs are not diy friendly. Refrigeration gauges are needed to assess, indirectly, loss of refrigerant while monitoring operating pressures whether performed with engine at idle or higher rpm (specified in service manuals).

  • Thank you for your answer, I working with a mechanic friend on fixing this. I just want to help on the side. Bought this part already: shop.advanceautoparts.com/p/… Aug 21 at 19:20
  • Our first fix attempt was to refill the refrigerant. Aug 21 at 19:21
  • Unless you're familiar with vehicle ac systems, it may be wiser not to attempt refilling your system since you have no idea if refrigerant leaked out, the flow sensor is faulty or both. You risk over filing a system that can result in overloading the compressor that can shut down from excessive high pressures. Try the magnet method to see if ac turns on and determine if cooling returns. If cold air returns, replace the flow sensor first. Use the ac as is. Refrain from adding refrigerant that may be full.
    – F Dryer
    Aug 22 at 0:07

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