Wave band LF MF HF VHF
Radio wave AM FM
Modulation Amplitude modulation Frequency modulationFrequency 30KHZ 300KHZ 3MHZ 30MHZ 300MHZ
2. Area coverage
Scope of AM and FM broadcasting coverage area differs greatly.
Sometimes although AM broadcast may be received clearly, FM
binaural broadcasting cannot be received. Not only listening zone of
FM binaural broadcasting is small, but also static noise or other
cacophony (noise) tends to occur.
3. Receiving problem
Notes:
Besides static noise problem, there is also interference, multiplex
and attenuation. These problems are not caused by electric cacophony,
but the problem of radio wave itself.
(1) Interference
Besides static noise problem, AM broadcast tends to receive
other types of noise, especially at night. This is because ionosphere
reflects AM radio wave at night, these interference electric waves
interfere with signals from the same signal source while entering into
vehicle antenna directly, this kind of noise is called "interference".
(2) Multiplex
Noise caused by radio wave reflected from barrier is called
"multiplex". When radio signal emitted by broadcast antenna is
reflected by high buildings or high mountains, and disturbs directly
received other signals, multiplex phenomenon occurs.
(3) Attenuation
Since its frequency is higher than AM, FM wave is more easily
reflected by high buildings or high mountains. Therefore, FM signal
often disappears gradually, or when vehicle is blocked by barrier, it
cannot receive any signal, such phenomenon is called "attenuation".Audio System -Audio System Description5-38Chapter 5 Audio SystemSection 1 Audio System DescriptionDescription:
1. Radio wave band
Wave bands used in radiobroadcast are as follows:
LF: low frequency MF: medium frequency HF: high frequency VHF: very high frequencyFM (stereo)
FM (non-stereo)
AMInterference
IonosphereMultiplexAttenuation
(1) Check LCD Illumination
a. Turn the ignition switch to ACC
b. Turn on radio assembly
c. Turn on the position light
Standard: The LCD indicator of the radio assembly goes on
Abnormal: go to step (7)
Normal: go to the next step
(2) Control volume and adjust the volume balance
Adjust the volume and its balance of the radio assembly to find out the inaudible speaker.
If all speakers are mute, check and replace the radio assembly
If individual speaker is mute, then respectively check and replace the inaudible speaker.
(3) Tweeter assembly inspection
a. Disconnect the speaker connector
b. Check the resistance
Notice:
Do not remove the speaker during inspection.
Standard Value: 4 ohm
Abnormal: Replace tweeter speaker assembly
Normal: Check wire harness and connector
(4) Check front speaker assembly
a. Disconnect speaker connector
b. Check resistance
Standard Value: 4 ohm
Abnormal: Replace front speaker assembly
Normal: Check wire harness and connector
(5) Check rear speaker assembly
a. Disconnect speaker connector
b. Check resistance
Standard Value: 4 ohm
Abnormal: Replace rear speaker assembly
Normal: Check wire harness and connector
(6) Check wire harness and connector
Abnormal Repair or replace wire harness and connector
Normal Check and replace radio assembly
(7) Check and replace radio assembly (+B, ACC, GND)
a. Check the continuity between terminals under each operating condition as shown in the table below.
Standard:Audio System -Audio System Inspection5-44Tester connection Condition Standard Status
GND Normal ON
Air Conditioning System -General Information5-75Air conditioner pressure switch plug-in unitInspection1. Check pressure switch
(a) Magnetic clutch control:
Check operation of pressure switch
( 1 ) Install manifold instrument
( 2 ) Connect positive meter pen of ohmmeter to terminal 4,
negative meter pen to terminal 1respectively.
( 3 ) As shown in the figure, check connection of each terminal
when refrigerant pressure changes
If operation does not conform to specification, replace
pressure switch.
(b) Check operation of condenser fan
( 1 ) Connect positive meter pen to terminal 2, negative meter pen to terminal 3 respectively.
( 2 ) As shown in the figure, check connection of each terminal when refrigerant pressure changes
If operation does not conform to specification, replace pressure switch.
2. Compressor magnetic clutch
(a) Connect positive pole of storage battery to binding post, negative pole to compressor shell.
(b) Check magnetic clutch in energized condition.
If abnormal, replace magnetic clutch.
3. Air conditioner thermistorThermistor plug-in unit (a) As shown in the figure, check resistance value of air conditioner thermistor
between terminal 1, 2 at each temperature,
Resistance:1
2Temperature(°C)Resistance
(K ohm)
Step Action of operator Screen displayResult in normal conditionPump motor works
Wheel lockup
Wheel lockup
Wheels may rotate freely,
pedal rebounds, work noise
of pump motor may be heard
Wheels may rotate freely
Wheel lockup, pedal auto-
matically goes down slightlyHydraulic control unit diagnosis -- hydraulic pump testLeft front wheel -- step down brake pedal
Left front wheel -- normally open valve opens,
normally closed valve is closed, wheel lockup?
Left front wheel -- normally open valve is closed,
normally closed valve is closed, wheel lockup?
Left front wheel _ _ normally open valve is closed,
normally closed valve opens, wheels may rotate
freelyLeft front wheel _ _ normally open valve is closed,
normally closed valve is closed, wheels may rotate freelyLeft front wheel -- normally open valve opens,
normally closed valve is closed, wheel lockup?
Release brake pedal 01
02
03
04
05
06
07
08Step down brake
pedal and hold
* Perform testing of the above steps 2-8 for each wheel. Sequence is as follows: left front right front left
rear right back.
* If result of one of the above steps is different from the result in normal condition, it shows that corresponding
actuator fails to work normally, please check corresponding actuator.
* Here as long as "return " position appears on the screen, it may finish the testing via "ESC " key and returns
to function menu.VI. Troubleshooting quick index tableMK-60 ABS system - ABS Diagnosis5-100Diagnostic
codeFault description Diagnosis contentCheck
list No.Reference
page
65535
01276
00283
00285
00290
00287
01044
00668
01130Electronic control unit
ABS hydraulic pump
Left front wheel sensor
Right front wheel sensor
Left rear wheel sensor
Right rear wheel sensor
ABS coding error
Supply terminal 30
ABS works abnormallyDamaged
Motor cannot work
Electric and mechanical failure
Signal lacks of conformity5-103
5-104
5-106
5-106
5-107
5-107
5-108 1
2, 3, 4
5
6
7
MK-60 ABS system -ABS System Check5-106Fault code is 00283, 00285, 00290, 00287 4
[Description]When identifiable open circuit, short circuit etc faults exist on
sensor, this fault code will appear.
[Prompt ] It might because poor contact of sensor, short circuit of coil or
wiring harness or faulty sensor signal processing circuit in ABS
ECUPossible cause
Sensor socket connector
or coil is disconnected
Sensor coil appear is
shorted
Sensor plug or wiring har-
ness is shorted with earth or
power supply
ABS ECU sensor signal
processing circuit failsCheck sensor of each wheel
Replace ABS ECURemove ABS ECU plug, check
whether resistance value between
the following terminals conforms
to standard value or not?
Standard value : 1.0-1.3K ohm¸
Left front : 45-46
Right front :33-34
Left rear : 36-37
Left rear: 42-43Check corresponding sensor
plugWhether fault recursCheck wiring harness between ECU and sensorRefer to key point for re-
pair of occasional fault Repair socket connector
Normal
No
YesAbnormal
AbnormalNormal Normal
Fault symptom
Flameout, poor idle speedChapter 9 Engine EFI SystemI. Outline This system includes sensor that detects engine functioning. Engine ECU utilizes sensors installed at differ-
ent parts of engine to measure various working parameters of engine, accurately control oil injection quantity
according to control procedure set in engine electronic control unit, so engine could work in optimum mode
under various operating conditions, i. e. optimal power output, the most economical oil consumption, optimal
exhaust emissions. Engine ECU is capable of start up control, idle speed closed-loop control, air fuel ratio
closed-loop control, canister control, transient operation control, angle of ignition control, knocking control, air
conditioning control, coasting fuel cutoff and overspeed fuel cutoff control, ternary catalyst heating and protec-
tion control, system self-diagnosis etc.II. Inspection of control element1. Manifold intake pressure temperature sensor
(1) The part to measure intake pressure is piezo type sensor, could provide controller with "load signal "
according to the difference between atmospheric pressure and manifold pressure; controller will supply 5V
voltage, and feed back 0-5V voltage to controller according to different intake pressures. The part to measure
intake temperature is NTC type (negative temperature coefficient) sensor, resistance changes with intake
temperature, this sensor conveys a voltage representing intake temperature change to the controller.
(2) Simple measuring method:
Temperature sensor part: (remove joint) turn digital multimeter
to Ohm position, two meter pens connect sensor 1 #, 2 # pinrespectively, rated resistance is 2. 5k ohm±5% at 20°C, correspond-ing resistance value may be measured from the above characteristic
curve. Simulation method may also be used for measurement, spe-
cific procedure is to use electric drier to blast sensor (pay attention not
to be too close), observe change of sensor resistance, here resistanceEngine EFI System-Engine EFI System5-120Possible cause
There is abnormal high voltage or reverse heavy current during useVacuum
unit is damaged during repair
Repair precautions: it is prohibit to use high pressure gas to impact vacuum unit during repair; when replace
sensor case of trouble, check whether generator output voltage and current is normal or not.1 2 3 4Manifold intake pressure temperature
sensor Intake pressure sensor feature cureIntake temperature feature curve
Output voltageAbsolute pressureTemperatureResistance
Fault symptom Possible cause
Poor speedup etc Man made fault1 2 3Throttle position sensorFault symptom Possible cause
Difficult to start Man made fault Repair precautions: pay attention to mounting position.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with sensor 1 #, 2 # pin respectively, its resistance
value at room temperature is 2k ohm±20 %. Connect two meter pens
with 1 #, 3# pin respectively, rotate throttle, its resistance value shows
linear change with opening of throttle, while situation is reverse for
2 #, 3# pin.
Note: when observe change of resistance value, pay attention to observe whether has large leap.
3. Coolant temperature sensor
(1) This sensor is a negative temperature coefficient (NTC) thermistor, its resistance value decreases with
increase of temperature, but not a linear relationship. This thermistor is installed in a copper heat conducting sleeve.Engine EFI System-Engine EFI System5-121should drop.
Pressure sensor part: (connect joint), turn digital multimeter to DC voltage position, black meter pen is earthed,
red meter pen is connected with 3#, 4# pin respectively. In condition of idle speed, 3# pin should have reference
voltage of 5 V, 4 # pin voltage should be about 1. 3 V (specific value is related with vehicle type); in no-load
condition, open the throttle slowly, change of voltage of 4 # pin is not large; open the throttle quickly, voltage of
4 # pin may reach about 4V in no time (specific value is related with vehicle type), then it drops down to about
1. 5 V.
2. Throttle position sensor
(1) This sensor is actually corner potentiometer with linear output characteristic. Potentiometer tumbler is
mounted coaxially with throttle, when throttle rotates, it drives potentiometer tumbler to slide to certain position,
potentiometer outputs voltage signal proportional to throttle position. Mounting torque: 20 N.m(Max)
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with sensor pins respectively,rated resistance at 20°C is 2.5 k ohm± 5%. Simulation method may also be used for measurement, specificprocedure is to put sensor work area into boiled water (pay attention to soak for sufficient time), observe changeof sensor resistance, now resistance should drop down to 300 ohm-400 ohm (specific value subjects to temperatureof boiled water).
Resistance value (K ohm)
No.Temperature
(°C) Temperature tolerance ±1°C Temperature tolerance ±0°C
Min. Max. Min. Max.
1 8.16 10.74 8.62 10.28 -10
2 2.27 2.73 2.37 2063 +20
3 0.290 0.354 0.299 0.345 +80
4. Knocking sensor
(1) Knocking sensor is a vibration acceleration sensor. Mounted on engine cylinder body. Sensing element of
the sensor is a piezocrystal. Vibration of engine cylinder body is transferred to piezocrystal via mass block in the
sensor. Since pressure generated by vibration of mass block is applied to piezocrystal, it generates voltage on two
polar planes and turns vibration signal into voltage signal for output.5-122Symptom
Poor accelerationPossible cause
Various liquids, such as engine oil, cooling fluid, brake fluid, water etc
contact the sensor for a long time, which cause corrosion to the sensor. Mounting torque: 20 ± 5 N.M
Repair precautions: sensor must be fitted closely to cylinder body with its metal surface, any type of washer
is not permitted for installation. For wiring of sensor signal cables, note that do not let resonance occur to signal
cables, otherwise they might be broken. Energizing of high voltage between sensor 1 # and 2 # pins must be
avoided, otherwise piezoelectric element might be damaged.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with sensor 1 #, 2 # pin
respectively, its resistance value at room temperature should exceed 1M ohm. Turn digital multimeter to millivolt
position, use a hand hammer to tap near knocking sensor, now voltage signal output should be available.
5. Oxygen sensor
(1) Its sensing element is a ceramic tube, outside is open to exhaust, inside is open to atmosphere. When
temperature of sensing ceramic tube reaches 350°C, it will have the characteristic of solid state electrolyte. Just
utilizing this characteristic, it converts concentration difference of oxygen into electric potential difference, thus
forms electrical signal output. If mixed gas is a bit concentrated, inside and outside oxyanion concentration
difference of ceramic tube is high, electric potential difference is a bit high.
A large number of oxyanions move from inside to outside, output voltage is high (approximate 900mV); if
mixed gas is a bit thin, inside and outside oxyanion concentration difference of ceramic tube is low, electric
potential difference is low, only a small quantity of oxyanions move from inside to outside, output voltage is low
(approximate 100mV).
Possible cause
1. humid water vapor ingresses inside of sensor, temperature
changes rapidly, probe is broken.
2. oxygen sensor "is poisoned". (Pb, S, Br, Si) Symptom
Poor idle speed, poor speedup, tail gas
overproof, too high oil consumption1 2 3 4Oxygen sensor Mounting torque: 40-60 N.m
Repair precautions: it is prohibited to use cleaning fluid, oily liquid or volatile solid on oxygen sensor during
repair.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with sensor 1# (white), 2# (white) pin respectively, its
resistance value at room temperature is 1- 6 ohm.
(Connect joint) in idle speed condition, when oxygen sensor
reaches its working temperature of 350°C, turn digital multimeter to
DC voltage position, connect two meter pens with sensor 3# (grey),Engine EFI System-Engine EFI System