Toyota Sienna Service Manual: Refrigerant

On-vehicle inspection

1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

(a) This method uses a manifold gauge set to locate problem areas. Read the manifold gauge pressure when these conditions are established.

Test conditions:

• Temperature at the air inlet is 30 to 35°C (86 to 95°F).
• Engine is running at 1,500 rpm.
• All doors are fully open.
• Blower speed control switch is at HI.
• Temperature control switch is at MAX. COOL.
• A/C switch is ON.

(b) Gauge readings (Reference)

(1) Normally functioning refrigeration system

Gauge reading

(2) The A/C system periodically changes between normal and improper function due to moisture in the refrigerant system.

(3) The A/C system does not function effectively due to insufficient cooling.

(4) The A/C system does not function effectively due to poor circulation of the refrigerant.

(5) The A/C system does not function intermittently because the refrigerant does not circulate.

(6) The A/C system does not function effectively due to overcharged refrigerant or insufficient cooling of the condenser.

(7) The A/C system does not function due to air in the refrigeration system.

(8) The A/C system does not function effectively due to an expansion valve malfunction.

(9) The A/C system does not function due to a defective compressor.

Gauge readings (Reference)