Isuzu KB P190. Manual — part 267

6E-34 Engine Control System (4JH1)

Step Action

Value(s)

Yes

No

2

1. Turn ON the ignition, with the engine OFF.
2. Attempt to establish communication with the

listed control modules.

• Engine control module (ECM)
• Transmission control module (TCM) (A/T

only)

• Electronic hydraulic control unit (EHCU)

Does the scan tool communicate with all the listed
control modules?



Go to Step 3

Go to scan tool

Does Not

Communicate with

Keyword 2000

Device

3

Attempt to start the engine.
Does the engine start and idle?



Go to Step 4

Go to Engine

Cranks but Does

Not Run

4

Select the DTC display function for the following
control modules:

• ECM
• TCM (A/T only)
• EHCU

Does the scan tool display any DTCs?



Go to Step 5

Go to Step 12

5

1. Turn OFF the ignition for 30 seconds.
2. Start the engine.
3. Monitor the DTC Information with the scan tool.
Did you complete the action?



Go to Step 6



6

Does the scan tool display ECM DTC P0602?



Go to Applicable

DTC

Go to Step 7

7

Does the scan tool display ECM DTC P0251
(Symptom Code 9 or A), P0606 (Symptom Code A
or B) or P1605 (Symptom Code C, D or E)?



Go to Applicable

DTC

Go to Step 8

8

Does the scan tool display ECM DTC P0560
(Symptom Code 1, 2 or A)?



Go to Applicable

DTC

Go to Step 9

9

Does the scan tool display following ECM DTC
P0561 (Symptom Code A or B) or P1625 (Symptom
Code A or B)?



Go to Applicable

DTC

Go to Step 10

10

Does the scan tool display following ECM DTC
P1650 (Symptom Code A or B) or P1651 (Symptom
Code A or B)?



Go to Applicable

DTC

Go to Step 11

11

Is there any other code in any controller that has not
been diagnosed?



Go to Applicable

DTC

Go to Step 12

12 Is the customer’s concern with the automatic

transmission?



Go to Diagnostic

System Check

Transmission

Control

Go to Step 13

13

Is the customer’s concern with the ABS system?



Go to Diagnostic

System Check

Brake Control

Go to Step 14

Engine Control System (4JH1) 6E-35

Step Action

Value(s)

Yes

No

14

1. Review the following symptoms.
2. Refer to the applicable symptom diagnostic

table:

• Hard Start
• Rough, Unstable, or Incorrect Idle and

Stalling

• Cuts Out, Misses
• Surge/Chuggles
• Lack of Power, Sluggishness, or

Sponginess

• Hesitation, Sag, Stumble
• Fuel Knock/Combustion Noise
• Poor Fuel Economy
• Excessive Smoke (Black Smoke)
• Excessive Smoke (White Smoke)

Did you find and correct the condition?



System OK

Go to Intermittent

Conditions

6E-36 Engine Control System (4JH1)

Scan Tool Data List

The scan tool Data List contains all engine related
parameters that are available on the scan tool. Use the
scan tool Data List only after the following is
determined:

• The Diagnostic System Check - Engine Controls is

completed.

• No diagnostic trouble codes (DTCs) are present.
• On-board diagnostics are functioning properly.

The scan tool values from a properly running engine
may be used for comparison with the engine you are
diagnosing. The scan tool Data List represents values
that would be seen on a normal running engine.
Important:
A scan tool that displays faulty data should not be used.
The scan tool problem should be reported to the
manufacturer. Use of a faulty scan tool can result in
misdiagnosis and unnecessary parts replacement. Only
the parameters listed below are referenced in this
service manual for use in diagnosis.

Scan Tool Parameter

Units Displayed

Typical Data Value at

Engine Idle

Typical Data Value at 2000

RPM

Operating Conditions: Engine Idling or 2000 RPM / Engine Coolant Temperature is between 75-85

°C (167-185°F) /

Accelerator Pedal is Constant / Park or Neutral / Accessories OFF / Vehicle Located at Sea Level

Ignition Switch

On/Off

On

On

System Voltage

V

11.0 – 15.0

11.0 – 15.0

ECM Main Relay

On/Off

On

On

Engine Speed

RPM

650 - 750

1950 – 2050

Desired Idle Speed

RPM

700

700

Injection Pump Speed

RPM

325 - 375

975 – 1025

Accelerator Pedal Position

%

0.0

5.0 – 7.0

Idle Switch

On/Off

On

Off

Intake Air Temperature

°C/°F

20 – 40°C / 68 – 104°F

20 – 40°C / 68 – 104°F

Engine Coolant Temperature

°C/°F

75 - 85

°C / 167 - 185°F

75 - 85

°C / 167 - 185°F

Fuel Temperature

°C/°F

20 – 60°C / 68 – 140°F

20 – 60°C / 68 – 140°F

Barometric Pressure

hPa

Nearly 1010 hPa at sea level Nearly 1010 hPa at sea level

Vacuum Pressure Sensor

hPa

Nearly 2020 hPa at sea level Nearly 2020 hPa at sea level

Turbocharger Solenoid Command

%

100% at sea level

100% at sea level

EGR Solenoid Command

%

Nearly 90%

Nearly 90%

Mass Air Flow Sensor

mg/strk

More than 430 mg/strk at sea

level (with EGR system)

More than 700 mg/strk at sea

level (without EGR system)

More than 430 mg/strk at sea

level (with EGR system)

More than 700 mg/strk at sea

level (without EGR system)

Desired Mass Air Flow

mg/strk

More than 430 mg/strk at sea

level (with EGR system)

1500 mg/strk (without EGR

system)

More than 430 mg/strk at sea

level (with EGR system)

1500 mg/strk (without EGR

system)

Actual Injection Quantity

mg/strk

6.0 – 9.0

7.0 – 11.0

Desired Injection Quantity

mg/strk

6.0 – 9.0

7.0 – 11.0

Actual Injection Timing

°CA

1.0 – 4.0

3.0 – 4.5

Desired Injection Timing

°CA

1.0 – 4.0

3.0 – 4.5

Neutral Switch

On/Off

On

On

Brake Pedal 1 Switch

Applied/ Released

Released

Released

Brake Pedal 2 Switch

Applied/ Released

Released

Released

Clutch Pedal Switch

Applied/ Released

Released

Released

Vehicle Speed

km/h / MPH

0

0

Engine Control System (4JH1) 6E-37

Scan Tool Parameter

Units Displayed

Typical Data Value at

Engine Idle

Typical Data Value at 2000

RPM

Glow Relay Command

On/Off

Off

Off

Glow Indicator Lamp Command

On/Off

Off

Off

Malfunction Indicator Lamp (MIL) Command

On/Off

Off

Off

A/C Request Signal

On/Off

Off

Off

A/C Relay Command

On/Off

Off

Off

Scan Tool Data Definitions

A list of each message displayed on the scan tool will
be explained in Engine Controls. This information will
assist in emission or driveability problems. The displays
can be viewed while the vehicle is being driven. Always
perform the Diagnosis System Check – Engine Controls
first. The Diagnostic System Check will confirm proper
system operation.
Ignition Switch
This parameter displays the input status of the ignition
switch to the ECM terminal (pin 39). The scan tool will
display On or Off. On indicates the ignition switch is
turned ON position.
System Voltage
This parameter displays the system voltage measured
by the ECM terminal (pin 3) at the voltage feed from the
ECM main relay.
ECM Main Relay
This parameter displays the commanded state of the
ECM main relay control circuit (pin 58). The scan tool
will display On or Off. On indicates the ECM main relay
control circuit is being grounded by the ECM, allowing
the main relay to supply voltage to the other circuits of
the ECM. Off indicates the main relay is not being
commanded On by the ECM.
Engine Speed
This parameter displays the speed of the crankshaft as
calculated by the ECM based on input from the
crankshaft position (CKP) sensor or camshaft position
(CMP) sensor. The scan tool will display the engine
speed in revolution per minute (RPM).

Desired Idle Speed
This parameter displays the idle speed requested by the
ECM. The ECM will compensate for various engine
loads based on engine coolant temperature (ECT) and
A/C system status. If the A/C system is activated, the
ECM sets 100 RPM higher than normal idle speed.
Injection Pump Speed
This parameter displays the speed of the injection pump
as calculated by the fuel injection pump control unit
(PCU) based on the input from the fuel injection pump
camshaft position (CMP) sensor. The scan tool will
display the injection pump speed in revolution per
minute (RPM).
Accelerator Pedal Position
This parameter displays the angle of the accelerator
pedal as calculated by the ECM using the signal from
the accelerator pedal position (APP) sensor. The
accelerator pedal position indicated angle is a range of
values indicating a low percentage when the accelerator
pedal is not depressed to a high percentage when the
accelerator pedal is fully depressed.
Idle Switch
This parameter displays the input status of the idle
switch to the ECM terminal (pin 69). The Tech will
display On or Off. On indicates the accelerator pedal is
not being pushed down. Off indicates the accelerator
pedal is being depressed.