AC Low Pressure Switch

This procedure covers the replacement of the AC low pressure switch on a 2019-2024 Toyota RAV4 with the 2.5L I4 gas engine. The switch monitors refrigerant pressure and is typically located on the AC suction line near the accumulator.

Warnings

Tools required

Parts

• AC low pressure switch × 1 — Use OEM specification
• O-ring for pressure switch × 1 — Usually included with switch

Fluids

• PAG 46 refrigerant oil — 0.1 qt
• R-134a refrigerant

Preparation

1. Verify AC system malfunction is related to low pressure switch (code P0533 or similar)
2. Ensure engine is cold and has not been running for at least 30 minutes
3. Park vehicle on level surface and engage parking brake
4. Have AC system professionally evacuated and refrigerant recovered if not already done

Procedure

1. 1

   Access the low pressure switch
   Open hood and locate the AC low pressure switch on the suction line (larger diameter line) between the evaporator and compressor. It is typically mounted on the accumulator/drier near the firewall on the passenger side. Clean the area around the switch with a shop towel to prevent contamination.
2. 2

   Disconnect electrical connector
   Press the tab on the electrical connector and pull straight back to disconnect it from the AC low pressure switch. Inspect the connector terminals for corrosion or damage.
3. 3

   Remove the old pressure switch
   Using a 19mm wrench, carefully unscrew the low pressure switch counterclockwise from the AC line fitting. Once loosened, remove by hand and immediately cap or cover the opening to prevent moisture and contamination from entering the system. Inspect the old O-ring for damage.
4. 4

   Prepare the new switch
   Remove the new AC low pressure switch from its packaging. If the new O-ring is separate, install it onto the switch threads. Lightly coat the O-ring with clean PAG 46 refrigerant oil (approximately 0.5ml) using a clean finger. Do not use petroleum-based lubricants.
5. 5

   Install the new pressure switch
   Thread the new pressure switch into the AC line fitting by hand, turning clockwise until hand-tight. Ensure the O-ring seats properly and the switch threads smoothly without cross-threading. Using a torque wrench and 19mm socket, tighten to specification.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
6. 6

   Reconnect electrical connector
   Push the electrical connector onto the new AC low pressure switch until it clicks into place. Ensure the connection is secure by gently pulling on the connector.
7. 7

   Evacuate and recharge AC system
   Connect AC recovery/recharge machine to the service ports. Evacuate the system for a minimum of 30 minutes to remove any moisture. After evacuation, verify system holds vacuum for at least 10 minutes. Recharge with R-134a refrigerant to the specification on the underhood label (typically 18-20 oz for this model). Add additional PAG oil if required per machine recommendations.

Reassembly

1. Verify all electrical connections are secure and properly locked
2. Ensure no tools or shop towels are left in engine compartment
3. Close hood securely

Verification

• Start the engine and turn AC to maximum cold with fan on high
• Verify compressor engages and cycles properly
• Check for refrigerant leaks around the new pressure switch using electronic leak detector or soap solution
• Confirm AC blows cold air with center vent temperature between 38-45°F at idle
• Using scan tool, verify no AC pressure-related diagnostic codes are present
• Test drive vehicle and confirm AC operates normally under various conditions

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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