Isuzu KB P190. Manual - part 440

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-143

Compare the BARO value to the range specified in
the altitude vs. barometric pressure table. Refer to
Altitude vs Barometric Pressure.

Is the BARO parameter within the range specified?

—

Go to Step 6

Go to Step 7

Inspect the following for possible causes of
high boost pressure.

• Misrouted turbocharger nozzle control

actuator vacuum hoses

• Turbocharger nozzle control actuator or

solenoid valve for a stuck condition.
Refer to Turbocharger Control System
Check in this section.

• Intake throttle valve sticking. Perform the

Intake Throttle Solenoid Control with a
scan tool

• Oil in the air induction tubing causing an

incorrect boost pressure sensor signal.
When there is adhesion of oil inside of
the tubing, intercooler or turbocharger it
needs to be wiped off.

Repair or replace as necessary.

Did you find and correction the condition?

—

Go to Step 10

Go to Diagnostic

Aids

Turn OFF the ignition.

Disconnect the boost pressure sensor
harness connector.

Inspect for an intermittent and for a poor
connection at the harness connector of the
boost pressure sensor (pin 2 of E-107).

Disconnect the ECM harness connector.

Inspect for an intermittent, for a poor
connection and corrosion at the harness
connector of the ECM (pin 23 of E-90).

Test for high resistance of the low reference
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.

Disconnect the BARO sensor harness
connector.

Inspect for an intermittent and for poor
connections at the harness connector of the
BARO sensor (pins 2 and 3 of E-40).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 18 and 19 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 9

Step

Action

Value(s)

Yes

6E-144 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Replace the boost pressure sensor. Refer to Boost
Pressure Sensor Replacement.

Did you complete the replacement?

—

Go to Step 10

—

Replace the BARO sensor. Refer to BARO Sensor
Replacement.

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.

Drive the vehicle that the Calculated Engine
Load parameter reaches at least 50% for
longer than 10 seconds (such as acceleration
on ramp) while comparing the Boost Pressure
to the Desired Boost Pressure.

Does the Boost Pressure parameter follow within
the specified value?

±20 kPa (±3

psi)

Go to Step 11

Go to Step 2

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

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-145

DTC P0299 (Flash Code 65)

Circuit Description

The boost pressure sensor is located in the air
induction tubing. The sensor is a transducer that varies
voltage according to changes in the air pressure inside
the air tubing. The ECM monitors the boost pressure
sensor signal for abnormal values. If the ECM detects
that the sensor signal is excessively low, this DTC will
set. This indicates excessive low boost pressure.

Condition for Running the DTC

• DTCs P0045, P0087, P0088, P0089, P0091,

P0092, P0093, P0101, P0102, P0103, P0107,
P0108, P0116, P0117, P0118, P0122, P0123,
P0192, P0193, P0401, P0403, P0404, P0405,
P0406, P0638, P0652, P0653, P0698, P0699,
P1064, P1065, P1093, P1404, P2100, P2101,
P2103, P2227, P2228 and P2229 are not set.

• The ignition switch is ON.

• The engine is running.

• The fuel injection quantity is higher than a

predetermined value.

Condition for Setting the DTC

• The ECM detects that the actual boost pressure is

more than 40 kPa (6 psi) below the desired boost
pressure under certain conditions for longer than
10 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 cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• Induction air leakage can cause a low boost

pressure condition. A whistling noise may be heard
if a component is allowing air to enter the induction
system.

• Check for cracked air tubing that may only open

during certain engine movement conditions.

• Misrouted vacuum hoses may set this DTC.

• Check the turbocharger nozzle control actuator for

a sticking. Refer to Turbocharger in the Engine
Mechanical section.

• Use a scan tool to verify the integrity of the boost

pressure sensor signal. Compare the Boost
Pressure to the Desired Boost Pressure under all
load conditions for an excessively low value.

• Loss of vacuum pressure or vacuum pump

problem sets this DTC.

Test Description

The numbers below refer to the step number on the
diagnostic table.
4. A skewed boost pressure sensor value (shifted to a
lower pressure) can set this DTC. The Boost Pressure
on the scan tool should read near Barometric Pressure
(BARO) with the key ON and engine OFF.
5. A skewed BARO sensor value (shifted to a higher
pressure) may indicate a wrong boost pressure. The
BARO on the scan tool should read near surrounding
barometric pressure.

Schematic Reference: Vacuum Hose Routing
Diagram and Engine Controls Schematics

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

Circuit/ System Testing DTC P0299

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 P0045, P0107, P0108, P2227, P2228 or
P2229 also set?

—

Go to Applicable

DTC

Go to Step 3

6E-146 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Inspect the following for possible causes of
low boost pressure.

• Air leakage around the boost pressure

sensor or objects that block the sensor
hole.

• Air leaking around any of the air induction

tubing between the turbocharger and
intake manifold. Check for damaged
components and for loose clamps.

• Misrouted, disconnected or kinked

turbocharger nozzle control actuator
vacuum hose.

• Turbine shaft binding causing lower

turbocharger shaft spinning speeds.
Refer to the Turbocharger in Engine
Mechanical section for diagnosis.

• Turbocharger nozzle control actuator or

solenoid valve for a stuck condition.
Refer to Turbocharger Control System
Check in this section.

• Intake throttle valve sticking. Perform the

Intake Throttle Solenoid Control with a
scan tool.

• Restricted air cleaner element, restricted

or collapsed air tubing between the air
cleaner and the boost pressure sensor.

• Oil in the air induction tubing causing an

incorrect boost pressure sensor signal.
When there is adhesion of oil inside of
the tubing, intercooler or turbocharger it
needs to be wiped off.

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 10

Go to Step 4

Turn ON the ignition, with the engine OFF.

Observe the Boost Pressure and Barometric
Pressure (BARO) with a scan tool.

Does the scan tool indicate that the difference
between the Boost Pressure and BARO is more
than the specified value?

10 kPa (1.5

psi)

Go to Step 5

Go to Diagnostic

Aids

Compare the BARO value to the range specified in
the altitude vs. barometric pressure table. Refer to
Altitude vs Barometric Pressure.

Is the BARO parameter within the range specified?

—

Go to Step 6

Go to Step 7

Step

Action

Value(s)

Yes

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