Chery A21 2005, Service Manual, Page: 352 / 475

CHERY
·
A21 SERVICE MANUAL ENGINE EFI SYSTEM
29
Short circuits from low-speed relay line to
ground
Open circuits of low-speed relay line
Engine coolant temperature sensor failure
Engine intake air temperature sensor failure
3.15 AIR CONDITIONER CONTROL
1)Working principle
Switch on the air conditioner and blower; air
conditioner
pressure is regular; evaporator
temperature sensor inspect the right data;
requirement signal of air conditioner is sending by
these switches to ECU, and ECU controls air
conditioning relay attracting and provide rotating
speed signal to step motor and open the electronic
fan and air conditioning chart to work.
2)Air conditioner control strategy
a) The air condition can be switched on after 5
seconds of the engine starts.
b) Cut off the air conditioner when temperature of
intake air higher than 140.3
℃
.
c) Cut off air conditioner when the coolant
temperature higher than 114.8
℃
; resume the air
conditioning control after its lower than 11.8 .
℃
d) Cut off air conditioner when the engine speed is
higher than 6520rpm or lower than 520rpm.
e) Cut off air conditioner when the pressure inside
of air conditioner high pressure pipe is higher
than 20bar and resume the control when the
pressure is lower than 9.5bar.
f) Cut off air conditioner when the evaporator
temperature is lower than 1.5
℃
; and resume the
control when it is higher than 4.5
℃
.
g) Cut off air conditioner when the system pressure
is lower than 8.04V; consume the control when
it is higher than 10.01V.
3) Malfunction diagnosis
Air Conditioner Compressor Clutch
Request Signal
Form Air
Conditioner
Power Supply
Chart 3-27 Air conditioner control
schematic
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