127
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5
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.malfaction, cause and correction
Malfuction
Cause
Correction
Vehicle cannot
start
Fuel pump.
fuel injector
IVM523
Check for operation by CHECK—UP1
Tachometer
senser.
Check wring, sensor resistance and installation of the
sensor.
Dual relays
Check for function, connector connection and blown fuse.
35——pin
connection
Check for the wiring connection to ECU.
Difficult to start;
idling speed too
high or too low
Engine idling
speed control
solenoid.
Check for solenoid operation and 4—pin connection by
CHECK—UP1.
Warning light on
During idling,
λ
sensor
Check for the wiring, proper sensor tightening torque and
the sensor heater’s operation
Warning light on
for a long time
Diagnosis
warning light
Check for the signal wiring grounding.
Warning light
doesn’t turn on
Diagnosis
warning light
The bulb is broken or circuit is open
Rough idling at
high temperature.
Throttle valve
sensor or water
temperature
sensor
The throttle valve opening angle and water temperature
signal displayed by CHECK—UP1 should match the engine
operation.
Rough idling at
low temperature.
Coolant
temperature
sensor or
intake air
temperature
sensor
The temperature indicated should be in the vicinity of the
ambient temperature.
Idle intermittent
wave
1—Throttle
valve body
30MM4
1.check the throttle valve cable for proper adjustment,
smooth movement. 2.if the throttle valve cable is correctly
adjusted and may move smoothly, remove it. Check the
throttle valve for resistance by turning it with a hand (for
friction)
；
3.display the throttle valve position by
CHECK—UP1. If both 1 and 2 are correct and engine speed
is still high, while CHECK—UP1 displays “angle is greater
than the allowable angle”, then the malfunction is positively
determined. It is necessary to replace the throttle valve
potentiometer. If the angle is within the specified range,
sensor wiring and connector should be checked.
Idling speed
fluctuates
continuously at
high temperature.
1.Throttle
valve body 1.2
Seal 1.3
Vacuum
connection
1. Check the above item 1,2,3 for intermittent idling speed
functions; 1.2 Check the seal between cylinder head and
throttle valve body; 1.3 Check the vacuum lines to the two
vacuum passages, which are of absolute pressure. Check the
fuel vapor recirculation passages, which are connected to
the throttle valve body and intake manifold. Check the
vacuum tube sealing in intake manifold for brake servo.
Vehicle
performance
deteriorates
1—Fuel supply
system
1. Check for fuel supply. If fuel pressure is 1
±
0.1bar, it
is ok; 2. If malfunction still remains after upper throttle
body (30mm12) is replaced, with a pressure regulator in the
upper throttle body, check fuel filter and fuel pipes.
