Isuzu KB P190. Manual - part 466

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-247

Turn OFF the ignition.

Disconnect the EGR valve harness connector.

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).

Disconnect the ECM harness connector.

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).

Test for high resistance on each circuit.

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

Did you find and correct the condition?

—

Go to Step 6

Go to Step 5

Replace the EGR valve. Refer to EGR Valve
Replacement.

Did you complete the replacement?

—

Go to Step 6

—

Reconnect all previously disconnected
harness connector(s).

Notice: Ignition switch must be cycled before clear
the DTC.

Turn ON the ignition, with the engine OFF.

Turn OFF the ignition for 30 seconds.

Turn ON the ignition and clear the DTCs with
a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 2

Go to Step 7

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

6E-248 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P1411, P1412 or P1413 (Flash Code 445)

Circuit Description

The ECM controls the EGR valve opening based on the
engine running condition and by controlling the EGR
solenoid. The EGR valve position is detected by the
position sensor, and relayed to the ECM. If the ECM
detects an excessively high temperature condition in its
internal EGR solenoid drive circuit for certain length of
time, DTC P1411, P1412 or P1413 will set.

Condition for Running the DTC

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects an excessively high temperature

in its internal EGR solenoid drive circuit for longer
than 30 seconds. (DTC P1411)

• The ECM detects an excessively high temperature

in its internal EGR solenoid drive circuit for longer
than 60 seconds in accumulation time during same
ignition cycle. (DTC P1412)

• The ECM detects an excessively high temperature

in its internal EGR solenoid drive circuit for longer
than 120 seconds in accumulation time exceeding
ignition cycle. (DTC P1413)

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• A sticking or intermittently sticking EGR valve may

set this DTC.

Circuit/ System Testing DTC P1411, P1412 or P1413

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the DTC Information with a scan tool.

Is DTC P0404 or P1404 also set?

—

Go to Applicable

DTC

Go to Step 3

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

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 (compare with a
similar unit if available)?

±5%

Go to Diagnostic

Aids

Go to Step 4

Remove the EGR valve assembly from the
engine.

Inspect the EGR valve for the following
conditions:

• Restricted EGR valve by foreign

materials

• Excessive deposits at valve

• Bent valve shaft

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 6

Go to Step 5

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-249

Replace the EGR valve. Refer to EGR Valve
Replacement.

Did you complete the replacement?

—

Go to Step 6

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 7

Go to Step 9

Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.

Did you complete the replacement?

—

Go to Step 8

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 2

Go to Step 9

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

6E-250 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P156A or P156B (Flash Code 135)

Circuit Description

The ECM monitors the battery voltage on the ECM
main relay voltage feed terminal to make sure that the
voltage stays within the proper range. If the ECM
detects an excessively low or high battery voltage, DTC
P156A or P156B will set.

Condition for Running the DTC

• The ignition voltage is more than 9 volts. (DTC

P156B)

Condition for Setting the DTC

• The ECM detects that the battery voltage feed

circuit is less than 8 volts for 20 seconds. (DTC
P156A)

• The ECM detects that the battery voltage feed

circuit is more than 16 volts for 5 seconds. (DTC
P156B)

Action Taken When the DTC Sets

• The ECM illuminates the SVS lamp when the

diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. (Euro 4 Specification)

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
(Except Euro 4 Specification)

• The ECM limits fuel injection quantity. (DTC

P156B)

• The ECM inhibits pilot injection. (DTC P156B)

• The ECM inhibits cruise control. (DTC P156B)

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the SVS Lamp/ DTC - Type C. (Euro 4
Specification)

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A. (Except Euro 4
Specification)

Diagnostic Aids

• A charging system problem may set this DTC.

• The weakened battery may set DTC P156A.

• Jump starting the vehicle or a battery charger may

have set DTC P156B.

Schematic Reference: Engine Controls Schematics

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

Circuit/ System Testing DTC P156A

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine and let idle.

Load the electrical system by turning ON the
headlights, A/C, etc. while observing the
Battery Voltage parameter with a scan tool.

Does the scan tool indicate more than the specified
value?

10.0 volts

Go to Diagnostic

Aids

Go to Step 3

Test the charging system. Refer to Diagnosis of
The Charging System in the Charging System
Section.

Did you find a charging system problem?

—

Go to Step 4

Go to Step 5

Repair the charging system. Refer to Diagnosis of
The Charging System in the Charging System
Section.

Did you complete the repair?

—

Go to Step 6

—

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