Isuzu KB P190. Manual - part 425

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-83

Important: The fuel supply pump must be timed to
the engine and adjustment value must be learned
to the ECM.
Notice: Always replace the fuel filter cartridge
when a fuel supply pump is replaced.
Replace the fuel supply pump and fuel filter
cartridge. Refer to Fuel Supply Pump Replacement
and Fuel Filter Cartridge Replacement.

Did you complete the replacement?

—

Go to Step 15

—

Notice: There is a possibility that the pressure
limiter valve did not active.
Replace the pressure limiter valve. Refer to Fuel
Rail Replacement.

Did you complete the replacement?

—

Go to Step 16

—

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 17

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-84 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0089 (Flash Code 151)

Description

The common rail fuel system is comprised of two fuel
pressure sections: a suction side between the fuel tank
and the fuel supply pump and a high-pressure side
between the fuel supply pump and the fuel injectors.
Fuel is drawn from the fuel tank via a feed pump and
then pumped into the fuel rail by two plungers, all of
which are internal to the fuel supply pump. This high
pressure is regulated by the ECM using the fuel rail
pressure (FRP) regulator dependant upon values from
the FRP sensor attached to the fuel rail. If the ECM
detects that fuel pressure is a certain pressure higher
than the desired pressure, this DTC will set.

Condition for Running the DTC

• DTCs P0091, P0092, P0192, P0193, P0652,

P0653, P0201 - P0204, P1064, P1065, P124B and
P2146 - P2151 are not set.

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

• The engine is running.

Condition for Setting the DTC

• The ECM detects that the actual fuel rail pressure

is more than 20 to 40 MPa (2,900 to 5,800 psi)
over the desired pressure for longer than 20
seconds.

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

• An intermittently sticking FRP regulator may have

allowed the fuel pressure to become high enough
to set this DTC.

• Normal Fuel Rail Pressure readings on the scan

tool with the engine running in neutral at idle is
around 27 to 33 MPa (3,900 to 4,800 psi) after
warm up.

• A skewed FRP sensor value can set this DTC. The

FRP Sensor on the scan tool should read 0.9 to
1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1
minute.

Schematic Reference: Fuel System Routing Diagram
and Engine Controls Schematics

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

Circuit/ System Testing DTC P0089

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 P0091, P0092, P0192, P0193, P0201 -
P0204, P0219, P1064, P1065, P124B or P2146 -
P2151 set?

—

Go to Applicable

DTC

Go to Step 3

Turn OFF the ignition.

Wait 1 minute for the fuel pressure to bleed
down from the fuel rail.

Turn ON the ignition, with the engine OFF. DO
NOT start the engine.

Observe the Fuel Rail Pressure (FRP) Sensor
parameter with the scan tool.

Does the scan tool indicate within the specified
value?

0.9 to 1.0 volt

Go to Step 4

Go to Step 5

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-85

Turn OFF the ignition.

Disconnect the FRP regulator harness
connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the FRP regulator (pins 1 and 2
of E-50).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 34, 50, 54 and 70
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 10

Go to Step 6

Turn OFF the ignition.

Disconnect the FRP sensor harness
connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the FRP sensor (pins 1, 2 and 3
of E-48).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 47, 48, 68 and 69
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 10

Go to Step 8

Turn OFF the ignition.

Place the transmission in Neutral and set the
parking brake.

Start the engine.

Accelerate the engine between idle and
W.O.T (accelerator pedal full travel) many
times while observing the Fuel Rail Pressure
and Desired Fuel Rail Pressure Parameter
with a scan tool.

Does the Fuel Pressure parameter follow within the
specified value quick enough (compare with a
similar unit if available)?

±5 MPa

(

±725 psi)

Go to Step 7

Go to Step 9

Notice: An intermittent problem by foreign material
in the fuel is suspected.
Replace the fuel filter cartridge. Refer to Fuel Filter
Cartridge Replacement.

Did you complete the replacement?

—

Go to Step 10

—

Replace the FRP sensor. Refer to FRP Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 10

—

Step

Action

Value(s)

Yes

6E-86 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Did you complete the replacement?

—

Go to Step 10

—

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 11

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

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