Isuzu KB P190. Manual - part 465

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-243

3

1.

Inspect for an intermittent, for poor tightening
and corrosion at the engine ground terminal
(E-10).

2.

Repair the tightening or clean the corrosion as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 4

4

1.

Test ground circuit between the ECM (pin 73
of E-90) and the engine ground terminal (E-
10) for an intermittently open circuit or high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 5

5

1.

Test the battery voltage feed circuit between
the ECM (pin 73 of E-90) and the ECM main
relay (pin 1 of X-12) for an intermittently open
circuit or high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 6

6

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pin 73 of C-58 and pin
73 of E-90).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7

7

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

Did you complete the replacement?

—

Go to Step 8

—

8

1.

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

2.

Clear the DTCs with a scan tool.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

5.

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 3

Go to Step 9

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

No

6E-244   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P1262 (Flash Code 34)

Circuit Description

The charge up circuit in the ECM steps up the voltage
for fuel injectors and is divided into two banks, common
1 and common 2. The common 1 covers fuel injectors
in cylinders #1 and #4, and the common 2 covers fuel
injectors in cylinders #2 and #3. If the common 2 fuel
injector charge up circuit in the ECM is an insufficient
charge or an overcharge, this DTC will set.

Condition for Running the DTC

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

• The engine is not running.

Condition for Setting the DTC

• The ECM detects that the common 2 fuel injector

charge up circuit is an insufficient charge or an
overcharge.

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 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.

Schematic Reference: Engine Controls Schematics

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

Circuit/ System Testing DTC P1262

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.

Start the engine.

4.

Monitor the DTC Information with a scan tool.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Step 8

3

1.

Inspect for an intermittent, for poor tightening
and corrosion at the engine ground terminal
(E-10).

2.

Repair the tightening or clean the corrosion as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 4

4

1.

Test ground circuit between the ECM (pin 73
of E-90) and the engine ground terminal (E-
10) for an intermittently open circuit or high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 5

5

1.

Test the battery voltage feed circuit between
the ECM (pin 73 of E-90) and the ECM main
relay (pin 1 of X-12) for an intermittently open
circuit or high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 6

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-245

6

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pin 73 of E-90 and pin
73 of C-58).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7

7

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

Did you complete the replacement?

—

Go to Step 8

—

8

1.

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

2.

Clear the DTCs with a scan tool.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

5.

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 3

Go to Step 9

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

No

6E-246   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P1404 (Flash Code 45)

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 that the actual EGR position is
higher than certain amount, this DTC will set. (Closed
Position Error DTC)
If the ECM detects a variance between the learned
closed position and actual closed position, this DTC will
also set. (Learned Position Error DTC)

Condition for Running the DTC

Closed Position Error DTC

• DTCs P0112, P0113, P0116, P0117, P0118,

P0404 P0405, P0406, P0652, P0653, P2227,
P2228 and P2229 are not set.

• The battery voltage is between 10 to 16 volts.

• The ignition switch is ON.

• The engine coolant temperature is between 20 to

110 

°C (68 to 230 °F).

• The intake air temperature is between 0 to 110 

°C

(32 to 230 

°F).

• The barometric pressure is between 60 to 120 kPa

(8.7 to 17.4 psi)

Learned Position Error DTC

• DTCs P0404, P0405 and P0406 are not set.

Condition for Setting the DTC

Closed Position Error DTC

• The ECM detects that the actual EGR position is

more than 20% for 5 seconds when the EGR
control is commanded OFF.

Learned Position Error DTC

• The ECM detects that the EGR learned minimum

position is more than 10% or less than -10% when
the ignition switch is OFF.

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 EGR control. (Closed Position

Error DTC)

• 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.

Schematic Reference: Engine Controls Schematics

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

Circuit/ System Testing DTC P1404

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.

Start the engine.

4.

Monitor the DTC Information with a scan tool.

Is DTC P0403, P0405 or P0406 also set?

—

Go to Applicable 

DTC

Go to Step 3

3

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 6

Go to Step 4