Data Stream Name

Ignition Switch

"ON"

Idle Speed

2,500 rpm

When

Diagnosis Description

Average Injector

Pulse Width

0.0 ms

3.2 ms

2.4 ms

Scan tool shows 0-16ms. It indicates that in each
engine cycle, the number of the engine control
module command connected to each injector.
The greater the fuel injector pulse width, the more
the fuel is injected. Injector pulse width (PWM)
increases as the engine load increases. If the
engine receives increasing torque signal, it will
increase the injection time. Many factors affect
the fuel injection time, such as engine coolant
temperature sensor, intake air temperature
sensor, power supply voltage and fuel pressure.

Cylinder No.1 Spark

Advance Angle

0°

6°

33.5°

At normal idle speed, the current ignition system
advance angle is 7° ahead of TDC. This value is
for repair reference only.

Knock Sensor Signal

1

0 V

0 V

0 V

ECM detects knock sensors amplitude and
frequency to control the ignition timing. Ignition
timing is placed in the position close to knocking
to get the maximum torque.

Knock Sensor Signal

2

0 V

0 V

0 V

Cylinder No.1 Ignition

Delay

0.0°

0.0°

0.0°

ECM calculates according to knock sensor
signals. If the knocking is detected, ECM controls
the ignition advance angle delay.

Cylinder No.2 Ignition

Delay

0.0°

0.0°

0.0°

Cylinder No.3 Ignition

Delay

0.0°

0.0°

0.0°

Cylinder No.4 Ignition

Delay

0.0°

0.0°

0.0°

Group 1 Oxygen

Sensor Integral Value

(Short-Term

Correction)

1.00

0.99

1.02

Based on feedback from oxygen sensor, increase
or decrease the basic injection duration with a
temporary value. It is useful only in the closed-
loop control. When it is a positive value, ECM will
increase the amount of fuel injected by increasing
the injection duration. When it is a negative value,
ECM will decrease the injection duration. When
the short-term value is continuously lower or
higher than the theoretical value, ECM will add
this value to the long-term fuel value or deduct it
from the long-term fuel value, in order to achieve
optimum Air-Fuel ratio control.

Engine

Control System JL4G18-D

2-59

Data Stream Name

Ignition Switch

"ON"

Idle Speed

2,500 rpm

When

Diagnosis Description

Group 1 Oxygen

Sensor Voltage 1

(Pre-Catalytic

Oxygen Sensor)

0.4 V

0.1-0.7 V

0.1-0.7 V

Under normal operating conditions, HO

2

S output

is 0.1-0.9V voltage. ECM receives this voltage
signal and measures whether the Air-Fuel ratio is
lean or rich. If ECM input signal voltage is lower
than 0.45V, the Air-Fuel ratio is lean; if the input
signal voltage is above 0.45V, the Air-Fuel ratio
is rich. In the closed-loop control, ECM
continuously detects HO

2

S output signal to

reduce or increase the fuel injection control pulse
width to adjust.

Group 1 Oxygen

Sensor Voltage 2

(Post-Catalytic

Oxygen Sensor)

0.6 V

0.7 V

0.7 V

The Post-Catalytic oxygen sensor is installed
after the catalytic converter or in exhaust pipe.
The Post-Catalytic oxygen sensor output voltage
is between 0 V-1V. Use the Post-Catalytic oxygen
sensor signal to detect the catalytic converter
efficiency. If the conversion efficiency of catalytic
converters is good, the Post-Catalytic oxygen
sensor signal is stable. If the catalytic converter
is aging, toxic or Misfire and so on, the conversion
efficiency of catalytic converters will decrease.
The Post-Catalytic oxygen sensor signal will be
similar to the Pre-Catalytic oxygen sensor signal.

Group 1 Oxygen

Sensor Integral Value

(Long-Term

Adjustments)

1.0

1.0

1.0

The long-term fuel adjustment value is stored in
ECM memory, because it is calculated as part of
the basic injection duration. It will not be deleted
when ignition switch is OFF. It affects the closed-
loop control and open-loop control injection
duration. ECM uses the short-term adjustment
value to modify the long-term fuel adjustment
value. It can not respond quickly to the instant
changes. It only changes when ECM decides to
use the short-term fuel adjustment value to adjust
the long-term fuel adjustment value. Like the
short-term fuel value adjustment, when the long-
term value is 0%, it indicates that the basic
injection duration does not need adjustment.
Positive percentage indicates the fuel injection
increase; while a negative percentage indicates
the fuel injection decrease. The long-term value
is for engine to control the entire range of injection
duration. It is divided into two categories; long-
term idle and long-term under load. When is
engine speed is lower than 920 rpm and the air
volume is 24kg/h, it monitors long-term idle.
Because the relatively small amount of intake air,

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Control System JL4G18-D

Engine

Data Stream Name

Ignition Switch

"ON"

Idle Speed

2,500 rpm

When

Diagnosis Description

Ultimate Long-term

Adjustment Factor

2.2%

2.2%

2.2%

adding more fuel or decrease fuel amount is need
to control idle speed. Different from long-term
idle, when the engine load is 30-75% and the air
volume is 40-200kg/h, it monitors the long-term
engine load and uses multiple-tuning to control
idle speed.

Intake Camshaft

PWM Control

5.86%

5.86%

5.8%

VVT intake camshaft position actuator current
actual opening changes from 0% to 100%. The
largest advance position is 100% and the
maximum lag position is 0%.

Intake Valve Opening

(As Opposed to

LWOT)

8°

8°

8°

Camshaft Overlap

Angle

494°

494°

494°

Idle Torque, Self

Learn

1.8%

1.8%

1.3%

-

Idle Speed Control

Target Torque

Adjustment

0.0%

-0.3%

0%

-

Engine Relative Load

100%

18.2%

14.7%

-

Run-Time After a

Speed Fault

0 min

0 min

0 min

-

Canister Control to

Fuel Injection Amount

0%

0%

1.2%

Using Canister solenoid valve opening duty cycle
control, the control signal is the pulse waveform
and can be detected with an oscilloscope. This

Engine

Control System JL4G18-D

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Data Stream Name

Ignition Switch

"ON"

Idle Speed

2,500 rpm

When

Diagnosis Description

Canister Control

Valve Duty Cycle

parameter shows the evaporative emission
control module commands (EVAP) solenoid
valve Canister clean-up power supply time or
duty cycle. 0% indicates that no clean-up carried
out and 100% indicates always clean-up.

0%

0%

100%

Canister Purification

Rate

0%

0%

0.1%

Fuel evaporative emission control system
prevents hydrocarbons (HC) overflow from the
fuel tank into the atmosphere, polluting the
environment. Collect the fuel vapor into the
Canister. ECM controls solenoid valve (EVAP) to
remove Canister collected fuel vapor steam and
make it into the engine for combustion. In the
actual repair work, compare the data stream to
the actual solenoid valve opening. If a leak
occurs, it is necessary to know how to determine.
Note that only when the engine reaches the
normal temperature, the data stream will increase
from a small value. When idling or engine cold,
the EVAP will not open.

Canister Load

1

3.2

0.7

2.2.7.10 Action Test Table

By reading the "Action Test Table" on the scan tool, you can check switches, sensors, actuators working state without removing any
parts. Before the control system diagnosis, carrying out action test is a prerequisite, so that the diagnose time could be shortened.

Note

Data under normal conditions is listed in the following table for reference only. Do not determine whether a part is faulty
solely based on these reference values. Under normal circumstances you can compare the vehicle that needs to be
repaired with a normal working vehicle in the same state to determine the current vehicle diagnostic data is normal or
not.

1. Run the engine to reach normal working temperature.

2. Turn the ignition switch to "OFF" position.

3. Connect scan tool.

4. Turn the ignition switch to "ON" position.

5. Select "engine"/"action test".

6. Refer to the following table to test.

Scan Tool Display

Item

Test Component

Control Range

Diagnosis Description

Fault Indicator

Enable the engine fault
indicator.

ON/OFF

When the engine is running (or) the ignition switch
is turned on, with the signal accepted, the engine
control module will request the fault indicator to
light through the CAN bus. The fault indicator will
be on or off in 3-5s.

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