361 

 
No. 263 Normal suction pressure and too high exhaust pressure for AC compressor   

Malfunction Cause 

Solution 

Air in system   

1) Air in system: Drain refrigerant and vent air out; pump vacuum and fill 
refrigerant again.   

Too much refrigerant   

2) Too much refrigerant: Discharge exceeding refrigerant.     

Condenser blocked 

3) Clog-up of condenser: Clean or replace condenser; pump vacuum and fill 
refrigerant again.   

Drying reservoir blocked 

4) Clog-up of drying reservoir: Replace drying reservoir; pump vacuum and 
fill refrigerant again.   

Pipeline blocked 

5) Clog-up of pipeline: Clear clog-up; pump vacuum and fill refrigerant 
again.  

Insufficient air amount of 
condenser fan   

6) Insufficient air amount of condenser fan: Replace fan.   

Normal suction 
pressure and too 
high exhaust 
pressure for AC 
compressor while 
running of vehicle 
AC 

High temperature of engine 
water tank   

7) High temperature of engine water tank: find the cause and remove it.   

 

 

Normal suction pressure and too high exhaust 
pressure for AC compressor 

Too much refrigerant 

Condenser blocked 

Air in system 

Drying reservoir blocked 

Pipeline blocked 

Insufficient air amount of condenser fan 

High temperature of engine water tank 

Check and repair 

Discharge 

Check, repair or replace 

Check, repair or replace 

Check, repair or replace 

Check, repair or replace 

Check, repair or replace 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Abnormal 

 
 

 

 

362 

 
No. 264 Too high suction pressure and exhaust pressure for AC compressor   

Malfunction Cause 

Solution 

Overdose of refrigerant   

1) Overdose of refrigerant: Discharge exceeding refrigerant.     

Malfunction of heat expansion 
valve  

2) Malfunction of heat expansion valve: Replace heat expansion valve.   

Broken suction valve segment 
of compressor   

3) Broken suction valve segment of compressor: Replace compressor.   

Over-high temperature of inlet 
air for evaporator   

4) Over-high temperature of inlet air for evaporator: Check if fresh air damper 
is closed tightly; find the cause and remove it.   

Air in system   

5) Air in system: Vent air in system out; pump vacuum and fill refrigerant again. 

Poor heat radiating for 
condenser  

6) Poor heat radiating for condenser: Check if fins of condenser are blocked by 
dirt and if fins are bent or distorted; clean or replace them.   

Insufficient air amount of 
condenser fan   

7) Insufficient air amount of condenser fan: Check if fan circuit is in poor 
contact, if the rotating speed of fan is normal and if there is too much dust on 
fins of condenser; find out the cause and remove it.   

 
Too high 
suction 
pressure and 
exhaust 
pressure for 
AC compressor 
while running 
of vehicle AC 

Loose fixing of temperature 
wrap  

8) Loose fixing of temperature wrap: The temperature wrap contacts badly with 
outlet of evaporator or outer heat isolating part of temperature wrap is broken; 
fix the temperature wrap again to ensure good heat isolating and contact of 
temperature wrap for heat expansion valve.   

 

Too-high suction pressure and exhaust pressure for AC 
compressor 

Overdose of refrigerant 

Fault of heat expansion valve 

Broken suction valve segment of 
compressor 

Too-high temperature of inlet air for 
evaporator

Air in system 

Poor heat radiating for condenser 

Insufficient air amount of condenser fan 

Loose fixing of temperature wrap 

Check and 
repair

Replace 

Check, repair or replace 

Check and 
repair

Check and 
repair 

Check, repair or replace 

Check, repair or replace 

Check and 
repair 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Normal 

Abnormal 

Abnormal 

 
 

 

 

363 

 
No. 265 Too high suction pressure and normal exhaust pressure for AC compressor   

Malfunction Cause 

Solution 

Too high temperature of inlet 
air for evaporator   

1)  Too high temperature of inlet air for evaporator: Check fresh air 

damper for leakage; the doors and windows should be closed to keep 
outside warm air away from carriage;   

Malfunction of heat expansion 
valve  

2) Malfunction of heat expansion valve: Replace heat expansion valve;   

Broken compressor   

3) Broken compressor: Replace compressor;   

Too high suction 
pressure and normal 
exhaust pressure for 
AC compressor 
while AC running   

Loosing or bad heat isolating 
of temperature wrap for heat 
expansion valve   

4) Loosing or bad heat isolating of temperature wrap for heat expansion 
valve: Tighten it to ensure good contact and enhance isolating protection; 

 

Check and 
repair 

Too high suction pressure and normal exhaust 

pressure for AC compressor 

Too high temperature of inlet 
air for evaporator 

Malfunction of heat expansion 
valve 

Broken compressor 

Loosing or poor heat isolating of 
temperature wrap for heat expansion 
valve 

Check and 
repair 

Check, repair or replace 

Replace 

Abnormal

Abnormal

Abnormal

Abnormal

 
 

 

 

364 

Too low suction pressure and exhaust 
pressure for AC compressor 

Insufficient refrigerant in system 

Malfunction of heat expansion 
valve 

Moisture in system 

Broken compressor 

Filling 

Checking, repairing or 
replacing 

Checking 
and repairing 

Checking, repairing or 
replacing 

 
No. 266 Too low suction pressure and exhaust pressure for AC compressor   

Malfunction Cause 

Solution 

Insufficient refrigerant in 
system  

1) Insufficient refrigerant in system: Check system for leakage; repair it and 
supplement refrigerant again;   

Malfunction of heat 
expansion valve   

2) Malfunction of heat expansion valve: Replace heat expansion valve;   

Moisture in system   

3) Moisture in system: Discharge refrigerant, replace drying filter and pump 
vacuum repeatedly (not less than 30 min) and fill refrigerant again;   

Too low suction 
pressure and 
exhaust pressure for 
AC compressor 
while running of 
vehicle AC 

Broken compressor   

4) Broken compressor: Replace compressor;   

 

 
 

Normal

Abnormal

Normal

Normal

Abnormal

Abnormal

Insufficient