Bosch AHUW036A2 Service Manual page 37

EEV valve operation
A
a
Fig. 35 EEV valve operation
[A] Valve open angle
[P] Pulse
[1] Close
[2] Open
[3] Fully open 1350 pulses
EEV failure check method
Failure mode
Microcomputer driving circuit
failure
EEV locking
EEV motor coil short or
misconnection
Table 41 EEV failure check method
Split ODU – 6 720 817 722 (2015/06)
1
2
3
P
6 720 817 722-31.1I
Diagnosis
1. Disconnect the EEV connector from
control board and connect testing
LED
2. Main power ON, pulse signal is out
from EEV for 17 seconds. If the LEDs
do not turn on, or are in on state
continuously, then the driving circuit
is abnormal
1. If EEV is locked, in no load state, the driving motor rotate
and clicking sound always occurs
1. Check the resistance between coil terminal (red-white, red-
yellow, red-orange, red-blue)
2. If the estimated resistance value is in 52 3 then the EEV
is normal
1. Check the resistance between coil terminal (brown-white,
brown-yellow, brown-orange, brown-blue)
2. If the estimated resistance value is in 150 10 then the
EEV is normal
• At power ON, open angle signal of 1400 pulses output and valve
position is set to
a
If valve operates smoothly, no noise and vibration occur and if valve
is closed. Noise occurs.
• Noise from the EEV can be confirmed by touching the EEV surface
with a screw driver and listening to the EEV noise.
• If liquid refrigerant is in EEV, the noise is lower.
Repair process
Check and replace unit control
board
1K LED
Replace EEV
Replace EEV
Replace EEV
Electronic expansion valve
Remark
Unit
37