How to Fix Toyota A/C Compressor Not Working Due to Flow Sensor Failure (Code B1479)

Troubleshooting Applicable for Toyota Altis 2010–2013, Camry 2013, and Lexus RX350

The A/C Flow Sensor in many Toyota models often fails after years of use, causing the A/C compressor to stop working.
When this sensor fails, the ECU detects incorrect refrigerant-flow data and triggers DTC Code B1479, preventing the compressor from engaging to protect the system.

This issue occurs even on vehicles with new genuine compressors, because the flow sensor inside the compressor can malfunction from heat, vibration, or manufacturing variation.

Symptoms of Flow Sensor Failure (B1479)

• A/C compressor not engaging

• Cooling fan not operating even when the A/C switch is ON

• No cold air

• Engine temperature still low but A/C does not start

• Scanner shows B1479 – A/C Flow Sensor Circuit

If “ B1479 ” appears → 100% Flow Sensor problem

How to Check the System

1. Start the engine and turn ON the A/C

• Cooling fan does not run

• Compressor does not engage

2. Check the Control Valve Connector (A/C compressor plug)

• Measure DC voltage

• There must be no constant 12V

• If no voltage appears → flow sensor is blocking the ECU from activating the compressor

3. Scan the car

If the scanner displays:

Code B1479 – Flow Sensor Circuit

Then the flow sensor is faulty and the compressor will not start.

🔧 How to Fix or Bypass the A/C Flow Sensor (Using “FLS”)

Troubleshooting You can solve this issue by using an FLS (Flow Sensor Simulator / Bypass Module).

How it works

• FLS bypasses the internal flow sensor

• Sends stable and correct signals to the ECU

• Allows the A/C compressor to operate normally

• No cutting or modifying the wiring

Installation

• Disconnect the original compressor flow-sensor plug

• Connect the FLS unit directly

• Plug-and-play design

• Fits Toyota Altis, Camry, Lexus RX350 (depending on model)

Your A/C system will begin working immediately after the FLS is connected.

🔧 What is FLS ?

FLS (Flow Sensor Simulator) is a plug-and-play module designed to bypass the damaged A/C Flow Sensor inside the Toyota compressor.

✔ No wiring modification
✔ No cutting
✔ Just unplug the old sensor and plug in FLS
✔ 100% compatible with Toyota Altis, Camry, Lexus RX350
✔ Fix the A/C compressor not engaging problem immediately
✔ Professional-grade automotive electronics

Conclusion

If your Toyota Altis, Camry, or Lexus RX350 shows B1479 and the A/C compressor does not work, the most common cause is a failed Flow Sensor.
Troubleshooting You can solve this issue by using an FLS (Flow Sensor Simulator / Bypass Module). Using an FLS Bypass Module is the quickest and safest way to fix the issue without replacing the entire compressor.

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