ON-VEHICLE INSPECTION
PROCEDURE
1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
HINT:
The following examples show the readings of a manifold gauge set and the corresponding air conditioning system problems.
(a) Read the manifold gauge pressure when the following conditions are met:
(1) Normally functioning air conditioning system Gauge Reading
|
|
(2) Abnormally functioning air conditioning system
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system periodically cools and then fails to cool |
Probable Cause |
Moisture in air conditioning system freezes at expansion valve orifice, causing refrigerant to temporarily stop circulating |
After system stops and warms up again, ice melts and normal operation is temporarily restored |
|
Diagnosis |
Cooler dryer (integrated into condenser tank) saturated with moisture |
Moisture in air conditioning system is freezing at expansion valve orifice and blocking circulation of refrigerant |
|
Corrective Actions |
Replace cooler dryer |
Remove moisture by repeatedly evacuating air from air conditioning system |
|
Recharge air conditioning system with proper amount of new or purified refrigerant |
HINT:
For the example above, moisture is present in the air conditioning system.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool effectively |
Insufficient cooling performance |
|
Probable Cause |
Refrigerant leaks from air conditioning system |
Diagnosis |
Insufficient refrigerant |
Refrigerant leaking |
|
Corrective Actions |
Check for refrigerant leaks and repair if necessary |
Recharge air conditioning system with proper amount of new or purified refrigerant |
|
If gauges indicate pressure of close to 0, then it is necessary to evacuate air conditioning system after repairing leaks |
HINT:
For the example above, there is insufficient refrigerant.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool effectively |
Frost exists on pipe from condenser to evaporator unit |
|
Probable Cause |
Refrigerant flow is obstructed by dirt inside pipes of condenser core |
Diagnosis |
Condenser is clogged |
Corrective Actions |
Replace condenser |
HINT:
For the example above, there is poor circulation of refrigerant.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool effectively (system may cool occasionally) |
Frost or condensation is seen on piping on both sides of receiver/dryer or expansion valve |
|
Probable Cause |
Refrigerant flow is obstructed by moisture or dirt in air conditioning system |
Expansion valve is stuck closed |
|
Diagnosis |
Refrigerant does not circulate |
Corrective Actions |
Replace expansion valve |
Replace condenser |
|
Evacuate air conditioning system and recharge with proper amount of new or purified refrigerant |
HINT:
For the example above, the refrigerant does not circulate.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool effectively |
Probable Cause |
Unable to provide sufficient performance due to excessive amount of refrigerant |
Cooling effectiveness of condenser is insufficient |
|
Diagnosis |
Excessive amount of refrigerant in air conditioning system because excessive refrigerant was added during recharging |
Cooling effectiveness of condenser is insufficient because condenser fins are clogged or cooling fan is faulty |
|
Corrective Actions |
Clean condenser |
Check operation of condenser cooling fan |
|
If condenser is clean and fan operation is normal, check amount of refrigerant and recharge air conditioning system with proper amount of new or purified refrigerant |
HINT:
For the example above, the air conditioning system is overcharged or cooling effectiveness of condenser is insufficient.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool |
The low pressure piping is too hot to touch |
|
Probable Cause |
Air in air conditioning system |
Diagnosis |
Air present in air conditioning system |
Insufficient vacuum purging when evacuating air conditioning system |
|
Corrective Actions |
Replace cooler dryer |
Check compressor oil to see if it is dirty or insufficient |
|
Evacuate air conditioning system and recharge it with new or purified refrigerant |
NOTICE:
These gauge indications occur when the air conditioning system has been left open and then recharged without evacuating the system.
HINT:
For the example above, air is present in the air conditioning system.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool effectively |
Frost or large amount of condensation on piping on low pressure side |
|
Probable Cause |
Expansion valve may be stuck open or metering refrigerant incorrectly |
Diagnosis |
Excessive refrigerant in low pressure piping |
Expansion valve open too wide |
|
Corrective Actions |
Replace expansion valve |
HINT:
For the example above, there is an expansion valve malfunction.
*a |
LO |
*b |
HI |
Symptom |
Air conditioning system does not cool effectively |
Probable Cause |
Internal leak in compressor |
Diagnosis |
Low compression |
Leak from damaged valve or other compressor component |
|
Corrective Actions |
Replace compressor |
HINT:
For the example above, there is insufficient compressor compression.
(3) Gauge readings (Reference)
*a |
Pressure on Low Pressure Side kPa (kgf/cm2, psi) |
*b |
Pressure on High Pressure Side kPa (kgf/cm2, psi) |
*c |
Blower High Zone |
*d |
Blower Low Zone |
Toyota CH-R Service Manual > Combination Meter: Disassembly
DISASSEMBLY
CAUTION / NOTICE / HINT
NOTICE:
When removing and installing the combination meter glass, make sure
not to touch the display panel.
Do not allow any dirt (fingerprints, grease, etc.) to adhere to the
combination meter glass. If the glass is dirty, wipe it clean wit ...
Toyota CH-R Service Manual > Air Conditioning System(for Automatic Air Conditioning System With Top-mounted
Air Conditioner Pressure Sensor): Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
HINT:
Use the table below to help determine the cause of problem symptoms.
If multiple suspected areas are listed, the potential causes of the symptoms
are listed in order of probability in the "Suspected Area" column of the
table. Check each sy ...