Toyota Venza manuals

Toyota Venza: On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

HINT:

This is a method where a manifold gauge set is used to help locate the problem.

(a) Read the manifold gauge pressure when the following conditions are met:

Test conditions:

  • Temperature at the air inlet with the switch set at RECIRC is 30 to 35°C (86 to 95°F).
  • The engine is running at 1500 rpm.
  • The blower speed control switch position is at "HI".
  • The temperature control dial position is at "COOL".
  • The A/C switch is on.
  • Doors are fully open.
  • The ignition switch is in a position that enables the A/C compressor to run.

(1) Normally functioning refrigeration system

Gauge Reading

Pressure Side

Refrigerant Volume

Low

150 to 250 kPa (1.5 to 2.5 kgf/cm2, 22 to 36 psi)

High

1370 to 1570 kPa (14.0 to 16.0 kgf/cm2, 199 to 228 psi)


(2) Moisture is present in the refrigeration system.


Symptom

Probable Cause

Diagnosis

Corrective Action

During operation, pressure on low pressure side cycles between normal and vacuum

  • Moisture in the AC system will freeze at the expansion valve orifice, causing the refrigeration cycle to temporarily stop
  • After the system stops, and warms up again, the ice will melt and normal operation will be temporarily restored
  • Cooler dryer (integrated into condenser tank) in oversaturated state
  • Moisture in refrigeration system freezes at expansion valve orifice and blocks circulation of refrigerant
  1. Replace cooler dryer
  2. Remove moisture in system by repeatedly evacuating air
  3. Supply a proper amount of new refrigerant

(3) Insufficient cooling


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Pressure is low on both low and high pressure sides
  • Bubbles are seen through sight glass continuously
  • Insufficient cooling performance

Gas leaks from the refrigeration system

  • Insufficient refrigerant
  • Refrigerant leaking
  1. Check for gas leaks and repair if necessary
  2. Supply a proper amount of new refrigerant
  3. If the gauge indicates a pressure of close to 0, then it will be necessary to evacuate the system after repairing the leak

(4) Poor circulation of refrigerant


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Pressure is low on both low and high pressure sides
  • Frost exists on pipe from condenser to unit

Refrigerant flow is obstructed by dirt inside the pipes of the condenser core

Receiver is clogged

Replace condenser

(5) Refrigerant does not circulate.


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Vacuum is indicated on low pressure side and very low pressure is indicated on high pressure side
  • Frost or condensation is seen on piping on both sides of receiver/drier or expansion valve
  • Refrigerant flow is obstructed by moisture or dirt in refrigeration system
  • Refrigerant flow is disrupted by gas leaks internally through the expansion valve

Refrigerant does not circulate

  1. Check expansion valve
  2. Replace expansion valve
  3. Replace condenser
  4. Evacuate air and supply a proper amount of new refrigerant
  5. For internal gas leaks at expansion valve, replace expansion valve

(6) Refrigerant is overcharged or cooling effectiveness of condenser is insufficient.


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Pressure is too high on both low and high pressure sides
  • No air bubbles are seen through sight glass even when engine rpm lowers
  • Unable to develop sufficient performance due to excessive use of refrigeration system
  • Cooling effectiveness of condenser is insufficient
  • Excessive refrigerant in cycle → excessive refrigerant was added during recharging
  • Condenser cooling effectiveness is insufficient → condenser fins are clogged at cooling fan
  1. Clean condenser
  2. Check the operation of the condenser cooling fan
  3. If 1 and 2 are normal state, check the amount of refrigerant and supply a proper amount of refrigerant

(7) Air is present in the refrigeration system.


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Pressure is too high on both low and high pressure sides
  • The low pressure piping is too hot to touch
  • Bubbles can be seen through sight glass

Air in system

  • Air present in refrigeration system
  • Insufficient vacuum purging
  1. Check compressor oil to see if it is dirty or insufficient
  2. Evacuate the system and recharge it with new or purified refrigerant

(8) Expansion valve malfunction


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Pressure is too high on both low and high pressure sides
  • Frost or a large amount of condensation on piping on low pressure side

Expansion valve may be stuck

  • Excessive refrigerant in low pressure piping
  • Expansion valve opened too wide

Check expansion valve

(9) Insufficient compressor compression


Symptom

Probable Cause

Diagnosis

Corrective Action

  • Pressure is too high on both low and high pressure sides
  • Pressure is too low on high pressure side

Internal leak in compressor

  • Low compression
  • Leak from a damaged valve, or parts may be broken

Replace compressor

Gauge readings (Reference)


Refrigerant
...

Replacement
REPLACEMENT PROCEDURE 1. RECOVER REFRIGERANT FROM REFRIGERATION SYSTEM (a) Start up the engine. (b) Turn the A/C switch on. (c) Operate the cooler compressor at an engine speed of approximately 1 ...

Other materials about Toyota Venza:

System Description
SYSTEM DESCRIPTION 1. WIRELESS DOOR LOCK CONTROL SYSTEM The wireless door lock control system functions to lock and unlock all the doors from a distance. The system is controlled by a door control transmitter which sends radio waves to the door control r ...

Front Passenger Side Door Entry Lock Function does not Operate
DESCRIPTION If the front passenger door entry unlock function operates normally, but its entry lock function does not, this means that the request code from the front passenger door is being output normally. In this case, a malfunction in the lock sensor ...

Removal
REMOVAL PROCEDURE 1. DISCHARGE FUEL SYSTEM PRESSURE HINT: (See page ). 2. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL CAUTION: When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ). 3. REMO ...

© 2016-2019 Copyright www.tovenza.com

0.2221