Chery A21 2005 Service Manual page 266

Fault descriptio n:
Badnes s idle speed, badness acceleration, badness tail gas, over fuel
consume et c.
Fault analysis：
Moist ure enterin g inside of s ensor, then the temper ature is ch anged and t he pin is br oken;
the sensor i s poisoned（ Pb,S,Br,Si）
:
Troubleshoot
（1） Disassemble joint， Put digital multimeter to ohm shift, connect meter pen to No.1
（white）and No.2（white） pins of the sensor. Normally the resistance value is 1~6Ω.
（2） Connect the joint and keep it at idle speed status. When the oxygen sensor reaches to
its working temperature 350℃, keep digital m ultimeter to DC volt shift and connect meter pen to
No.3 （gray） and No.4（ black） pins of sensor. Now the voltage should be fluctuate between
0.1- 0.9V quickly （the data also can be gotten from data f low inspected by diagnosis meter）.
（8）Vehicle speed sensor
Vehicl e speed sen sor
T he 1st pin of the vehicle speed s ensor connect t o power
T he 2nd pin conn ect to ground
T he 3rd pin is th e vehicle speed s ignal, it conne c t to the
59 th pin of engin e ECU.
Figur e9-12 Ve hicle spee d sensor a nd its circ uit
（9）A/C pressure switch
A/ C high/low pr essure
switch
The 2nd pin of A/C high/l ow pressure swit ch connect to the 75th pin of ECU; the 3rd pin conne ct to the
60th pin of ECU; the 1st 4th pin connect to the B19 switch of A/C module.
、
Fig ure9-13 A/C pressure switch and its ci rcuit
18
（10）Clutch pedal switch
ECU
59
T o fuse FB5
（11） Power steering switch
3
1 2
Ve hicle spe ed senso r
ECU
75 60
V/W Br/B
2 3
High/Low
pressure Switch
1 4
To The
Air Conditioner
Module B19 (AC Switch)
The 1st pin of clutch pedal swit ch is connec tted
to the 74 th pin of ECU, and the other pin is
connect ted to grou nd.
Clutch pedal switch
Figu re9-14 Clutch pedal swit ch and it s circuit
E CU
76
L
Pow er
In stallation position of
Steering Switch
power steering switch
Figure9-15 Power St eering switch and it s circuit
ECU
74
Sb/B
ECU/A1/7
Clutch
Pedal
Switch
The 1st pin of the power steering
switch is connectted to the 76th
pin of engine ECU, and the
other pin is connectted to ground.