Chery A18. Manual — part 24

6) Unstable idle speed at all time

Yes

Fix the indicated

malfunction

1

Turn the ignition switch to “ON”
position. Inspect with the diagnostic
tester to see whether there is any
malfunction information record.

No

Proceed to next step.

Yes

Repair or replace idle

speed actuator

2

Verify that the EWD3 idle speed actuator
or idle speed actuator with step motor is
jammed.

No

Proceed to next step.

Yes

Inspect the wiring

harness and plug in

connector

3

Connect the ignition switch and verify
that the links between water temperature
sensor, idle speed step motor and ECU
are properly connected.

No

Proceed to next step.

Yes

Proceed to Step 8

4

Run the engine at idle speed and cut off
the cylinders one by one in order to
observe whether the speed is decreasing
or fluctuating.

No

Proceed to next step.

Yes

Proceed to next step.

5

Verify that the fuel injector of each
cylinder functions normally.

No

Inspect the fuel injector

and the wiring harness

Yes

Proceed to next step.

6

Verify that the resistance of each cylinder
high voltage cable is normal.

No

Replace

Yes

Replace

7

Verify that the ignition coil is damaged.

No

Proceed to next step.

Yes

Proceed to next step.

8

Verify that the spark plug is normal.

No

Replace the spark plug

Yes

Proceed to next step.

9

Connect the fuel manometer valve. Short
the 30# and 87# pins of the fuel pump
relay to operate the fuel pump in order to
verify that the fuel pressure is being
maintained at about 350kPa.

No

Proceed to Step 13.

Yes

Proceed to Step 12.

10

Provide a voltage supply of 12V with
special connector between the battery and
the fuel injector, and verify that the fuel
injector functions normally.

No

Proceed to next step.

Yes

Proceed to next step.

11

After washing and cleaning the fuel
injector, verify again that it can function
normally.

No

Replace the fuel injector

Yes

Replace the fuel

12

Verify that the fuel is deteriorated or
contaminated with water.

No

Proceed to Step 18

Yes

Proceed to next step.

13

Verify that the fuel pressure is lower than
350kPa.

No

Proceed to Step 17.

14

Close the fuel manometer valve. Connect

Yes

Proceed to next step.

the ignition switch again to re-operate the
fuel pump in order to verify that the fuel
pressure can be established.

No

Proceed to Step 16.

Yes

Replace the fuel pressure

regulator

15

Open the fuel manometer valve and
clamp the fuel return pipe with the fuel
tube clamp to stop the fuel return in order
to verify that the fuel pressure can be
established quickly.

No

Repair or replace the fuel

injector or fuel pipe

Yes

Repair or replace the fuel

air inlet pipe

16

Verify that the fuel inlet pipe has any
leakage or blockage.

No

Replace the fuel pump

Yes

Repair or replace the fuel

return pipe

17

Verify that the fuel return pipe has any
leakage or bending.

No

Replace the fuel pressure

regulator

Yes

Clean

18

Verify that the sensing holes of the
pressure and temperature sensor of air
intake manifold have any blockages.

No

Proceed to next step.

Yes

Proceed to next step.

19

Run the engine at idle speed. When the
coolant

temperature

reaches

the

temperature of activating the close- loop
control, verify that oxygen sensor
functions normally. (Fluctuating within
the range of 0-1V)

No

Inspect the oxygen

sensor and the wiring

harness

Yes

Fix the leakage

20

Verify that the engine air intake system
has any leakage.

No

Proceed to next step.

Yes

Proceed to next step.

21

Verify that the pressure of engine
cylinder is normal.

No

Fix the malfunction

Yes

Replace the ECU.

22

Run the engine at idle speed until the
coolant temperature reaches its normal
range in order to verify that the ignition
advance angle is normal.

No

Inspect other items

7) Unstable idle speed during engine warm-up

Yes

Fix the indicated

malfunction

1

Turn the ignition switch to “ON” position.
Inspect with the diagnostic tester to see
whether there is any malfunction information
record.

No

Proceed to next step.

Yes

Proceed to next step.

2

Verify that the air filter is free of any blockage.

No

Replace

Yes

Proceed to next step.

3

Run the engine at idle speed. Verify that the air
intake

manifold pressure

is

maintained

between 35-65 kPa during warm-up.

No

Fix the leakage of air

intake system

Yes

Proceed to next step.

4

Shut down the engine. Turn on the ignition
switch and connect the adaptor between ECU
and the wiring harness. Verify that the voltages
at air intake temperature sensor, water
temperature sensor, and ECU’s pins of 32# and
33# (used as sensor power supply of 4.5-5V)
are normal.

No

Service

Yes

Proceed to next step.

5

Disconnect the connector of idle speed actuator
before ending the engine warm-up and verify
that the engine speed is changed.

No

Replace the idle

speed actuator

Yes

Proceed to next step.

6

Verify that the coolant temperature sensor is
normal.

No

Replace

Yes

Replace the ECU.

7

Run the engine at idle speed until the coolant
temperature reaches its normal range in order
to verify that the ignition advance angle is
normal.

No

Inspect other items

8) Unstable idle speed or stall with load (A/C and etc.)

Yes

Fix the indicated

malfunction

1

Turn the ignition switch to “ON” position.
Inspect with the diagnostic tester to see
whether

there

is

any

malfunction

information record.

No

Proceed to next step.

Yes

Proceed to next step.

2

Turn on the A/C switch and connect the
adaptor between ECU and the wiring
harness. Measure and see whether the
ECU’s A/C switch and pressure signal
have any signal input.

No

Overhaul the A/C

circuit.

Yes

Proceed to next step.

3

Verify that the pressure of A/C system,
the magnetic clutch of compressor and
A/C pump are normal.

No

Repair or replace.

Yes

Proceed to next step.

4

Turn the ignition switch to “ON” position.
Verify that the voltages at ECU’s pins of
65#, 64#, 67#, and 66# (output connected
to idle actuator) are normal.

No

Inspect the control

circuit.

Yes

Repair or replace the

step motor.

5

Remove the step motor to verify that it is
jammed or runs unfreely.

No

Proceed to next step.

Yes

Replace the ECU.

6

Start up the engine and turn on the A/C.
Inspect with the diagnostic tester through
the step amount of step motor to see
whether the idle actuator functions
normally. (The normal step amount will
be provided otherwise)

No

Replace the idle

actuator.