Isuzu KB P190. Manual - part 480

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-303

3

1.

Inspect the following conditions:

• An EGR valve gasket that is missing or

damaged

• A sticking EGR valve

• EGR gas leakage any of the EGR

passage between the exhaust manifold
and intake manifold

• Restricted or collapsed EGR passage

between the exhaust manifold and the
EGR valve

• Any type of restriction in the exhaust

system

• Restricted air cleaner element, restricted

or collapsed air tubing between the air
cleaner and the intake manifold

• Any air induction leak

• Any water intrusion in the induction

system

• Any contamination or objects that block

the MAF sensor inlet

• Skewed or slow MAF sensor

• Skewed engine coolant temperature

(ECT) sensor. Refer to Temperature vs
Resistance table to test the ECT sensor
at various temperature levels to evaluate
the possibility of a skewed sensor.

• Skewed barometric pressure (BARO)

sensor. Determine the outside barometric
pressure from you location specified in
the altitude vs barometric pressure table.
Refer to Altitude vs Barometric Pressure.

• A sticking intake throttle valve

2.

Repair the condition as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 4

4

1.

Place the transmission in Neutral and set the
parking brake.

2.

Start the engine and warm up (arrow engine
coolant temperature to reach at least 60

°C

[140

°F]).

3.

Accelerate the engine between idle and
W.O.T (accelerator pedal full travel) many
times while observing the Desired EGR
Position and EGR Position parameter with a
scan tool.

Does the EGR Position parameter follow within the
specified value?

±5%

Go to Step 5

Go to Step 8

5

1.

Perform the EGR Solenoid Control with a scan
tool several times.

2.

Command the Desired EGR Position Increase
and Decrease while observing the EGR
Position.

Does the EGR Position parameter follow within the
specified value quick enough?

±5%

Go to Step 6

Go to Step 8

Step

Action

Value(s)

Yes

No

6E-304   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

6

Notice:  If the intake throttle solenoid is
commanded OFF, Intake Throttle Position
parameter indicates over 100%.
Observe the Desired Intake Throttle Position and
Intake Throttle Position parameter with a scan tool.

Does the Intake Throttle Position parameter follow
within the specified value?

±5%

Go to Step 7

Go to Step 10

7

1.

Perform the Intake Throttle Solenoid Control
with a scan tool several times.

2.

Command the Desired Intake Throttle Position
Increase and Decrease while observing the
Intake Throttle Position.

Does the Intake Throttle Position parameter follow
within the specified value quick enough?

±5%

System OK

Go to Step 10

8

1.

Remove the EGR valve assembly from the
engine.

2.

Inspect the EGR valve for the following
conditions:

• Restricted EGR valve by foreign

materials

• Excessive deposits at valve

• Bent valve shaft

3.

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 9

9

1.

Turn OFF the ignition.

2.

Disconnect the EGR valve harness connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the EGR valve (pins 1, 2, 3, 4
and 6 of E-71).

4.

Disconnect the ECM harness connector.

5.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 30, 31, 32, 62 and
63 of E-90).

6.

Test for high resistance on each circuit.

7.

Repair the connection(s) or circuit(s) as
necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 12

10

1.

Remove the intake duct that is connected to
the intake throttle valve.

2.

Inspect the intake throttle valve for the
following conditions:

• Restricted intake throttle valve by foreign

materials

• Excessive deposits at throttle bore

• Bent butterfly valve

Notice: Replace the intake throttle valve is there is
any sticking

3.

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 11

Step

Action

Value(s)

Yes

No

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-305

11

1.

Turn OFF the ignition.

2.

Disconnect the intake throttle valve harness
connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the intake throttle valve (pins 1,
2, 3, 5 and 6 of E-38).

4.

Disconnect the ECM harness connector.

5.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 35, 36, 55, 56 and
57 of E-90).

6.

Test for high resistance on each circuit.

7.

Repair the connection(s) or circuit(s) as
necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 13

12

Replace the EGR valve. Refer to EGR valve
Replacement.

Did you complete the replacement?

—

Go to Step 14

—

13

Replace the intake throttle valve. Refer to Intake
Throttle Valve Replacement.

Did you complete the replacement?

—

Go to Step 14

—

14

Reconnect all previously disconnected components
or harness connector(s).

Did you complete the action?

—

Go to Step 2

—

Step

Action

Value(s)

Yes

No

6E-306   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Glow Control System Check

Description

The glow control system consists of the ECM, the glow
relay, the glow indicator lamp and glow plugs. The glow
control system is operated when the engine coolant
temperature is low, which allows easier engine starting.
The ECM commands the glow relay ON for a certain
length of time at ignition switch is ON with engine OFF.
In after glow phase, the glow plugs remain energized
for a certain period with engine run.

Glow Control Operation

• The glow indicator lamp illuminates between 0.5

seconds to 7 seconds depending upon the engine
coolant temperature.

• The pre glow control system operates when the

engine coolant temperature is less than 30

°C

(86

°F).

• The after glow control system operates when the

engine coolant temperature is less than 60

°C

(140

°F).

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing Glow Control System Check (1 of 2)

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic 

System Check - 
Engine Controls

2

1.

Install a scan tool.

2.

Turn OFF the ignition for 30 seconds.

3.

Turn ON the ignition, with the engine OFF.

4.

Monitor the DTC Information with a scan tool.

Is DTC P0117, P0118 or P0380 set?

—

Refer to Applicable 

DTC

Go to Step 3

3

Notice: If no glow indicator lamp is equipped, skip
to Step 3.

1.

Verify whether the instrument panel (IP)
cluster is operational.

2.

Perform the Glow Plug Lamp Control with a
scan tool.

3.

Command the lamp ON and OFF.

Does the glow indicator lamp turn ON and OFF
with each command?

—

Go to Step 4

Go to 2 of 2 Step 1

4

1.

Turn OFF the ignition.

2.

Make sure the metal bus bar that connects
switched battery voltage supply terminal (E-
49) and all glow plugs is secured tightly.

3.

Turn ON the ignition, with the engine OFF

4.

Connect a test lamp between the metal bus
bar (glow plug power supply E-49 terminal)
and a known good ground.

5.

Perform the Glow Relay Control with a scan
tool.

6.

Command the relay ON while observing the
test lamp.

Does the test lamp turn ON only when commanded
ON?

—

Go to Step 5

Go to Step 6