Refrigerant Flow Sensor on Variable Displacement Compressor
Variable displacement compressors are hard to diagnose as they are more than just a compressor. In addition to common malfunctions, there are other factors that can cause the compressor to seem as if it’s not working.
One new piece of technology that can add to the confusion is a flow sensor. These are fitted to the compressor and are used to send a signal back to the ECU. It is located in the discharge side and “reports” if there is refrigerant being pumped out of the compressor.
The ECU already knows the flow rate based on the engine speed, angle of the compressor swash plate and environmental factors. If the ECU is not receiving the correct signal, the problem could originate from a defective compressor or receiving an incorrect signal from the compressor, which will stop the compressor from pumping. This incorrect signal could result from a faulty sensor or an aftermarket compressor. The aftermarket manufacturer could be unaware that a flow sensor had been installed from OE..
If you have a system that operates when the engine first starts, but then stops cooling after 15 minutes, try restarting the vehicle. If the fault occurs again, there is a chance it may be the flow sensor turning the compressor off.
One new piece of technology that can add to the confusion is a flow sensor. These are fitted to the compressor and are used to send a signal back to the ECU. It is located in the discharge side and “reports” if there is refrigerant being pumped out of the compressor.
The ECU already knows the flow rate based on the engine speed, angle of the compressor swash plate and environmental factors. If the ECU is not receiving the correct signal, the problem could originate from a defective compressor or receiving an incorrect signal from the compressor, which will stop the compressor from pumping. This incorrect signal could result from a faulty sensor or an aftermarket compressor. The aftermarket manufacturer could be unaware that a flow sensor had been installed from OE..
If you have a system that operates when the engine first starts, but then stops cooling after 15 minutes, try restarting the vehicle. If the fault occurs again, there is a chance it may be the flow sensor turning the compressor off.
Part Number |
Application |
6513069 |
2011 - 2016 Scion tC |
6513068 |
2010 - 2016 Subaru Outback 2010 - 2016 Subaru Legacy |
6512920 |
2011 - 2013 Toyota Corolla |
6512815 |
2012 - 2016 Toyota Camry 2009 - 2012 Toyota Rav4 |

72_refrigerant_flow_sensor-_variable_displacement_compressor.pdf |