Isuzu KB P190. Manual - part 430

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-103

5

Connect a 3-amp fused jumper wire between the 5
volts reference circuit and the signal circuit (pins 3
and 1 of E-107).

Is the Boost Pressure Sensor parameter more than
the specified value?

4.7 volts

Go to Step 8

Go to Step 7

6

1.

Test the 5 volts reference circuit between the
ECM (pin 20 of E-90) and the boost pressure
sensor (pin 3 of E-107) for an open circuit or
high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

7

1.

Test the signal circuit between the ECM (pin
21 of E-90) and the boost pressure sensor
(pin 1 of E-107) for the following conditions:

• An open circuit

• A short to ground

• A short to the low reference circuit

• High resistance

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

8

1.

Inspect for an intermittent and for poor
connections at the harness connector of the
boost pressure sensor (pins 1 and 3 of E-107).

2.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 10

9

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent and for poor
connections at the harness connector of the
ECM (pins 20 and 21 of E-90).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 11

10

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

Did you complete the replacement?

—

Go to Step 12

—

11

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

Did you complete the replacement?

—

Go to Step 12

—

12

1.

Reconnect all previously disconnected
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 13

Step

Action

Value(s)

Yes

No

6E-104   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Circuit/ System Testing DTC P0108

13

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

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.

Observe the Boost Pressure Sensor
parameter with a scan tool.

Is the Boost Pressure Sensor parameter more than
the specified value?

4.7 volts

Go to Step 3

Go to Diagnostic 

Aids

3

Monitor the DTC Information with a scan tool.

Is DTC P0699 also set?

—

Go to Step 4

Go to Step 5

4

1.

Turn OFF the ignition.

2.

Disconnect the boost pressure sensor
harness connector.

3.

Turn ON the ignition, with the engine OFF.

Is the Boost Pressure Sensor parameter less than
the specified value?

0.1 volts

Go to DTC P0699

Go to Step 7

5

1.

Turn OFF the ignition.

2.

Disconnect the boost pressure sensor
harness connector.

3.

Turn ON the ignition, with the engine OFF.

Is the Boost Pressure Sensor parameter less than
the specified value?

0.1 volts

Go to Step 6

Go to Step 7

6

Connect a test lamp between the low reference
circuit (pin 2 of E-107) and battery voltage.

Does the test lamp illuminate?

—

Go to Step 9

Go to Step 8

7

Important: The boost pressure sensor may be
damaged if the sensor signal circuit is shorted to a
voltage source.

1.

Test the signal circuit between the ECM (pin
21 of E-90) and the boost pressure sensor
(pin 1 of E-107) for the following conditions:

• A short to battery or ignition voltage

• A short to any 5 volts reference

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 13

Go to Step 12

8

1.

Test the low reference circuit between the
ECM (pin 23 of E-90) and the boost pressure
sensor (pin 2 of E-107) for an open circuit or
high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 13

Go to Step 10

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-105

9

1.

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

2.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 13

Go to Step 11

10

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

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

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 13

Go to Step 12

11

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

Did you complete the replacement?

—

Go to Step 13

—

12

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

Did you complete the replacement?

—

Go to Step 13

—

13

1.

Reconnect all previously disconnected
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 2

Go to Step 14

14

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-106   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0112 or P0113 (Flash Code 22)

Circuit Description

The intake air temperature (IAT) sensor is fitted
between the air cleaner and turbocharger. It is internal
to the mass air flow (MAF) sensor. The IAT sensor is a
variable resistor and it measures the temperature of the
air entering the engine. The sensor has a signal circuit
and a low reference circuit. The ECM supplies 5 volts to
the signal circuit and a ground for the low reference
circuit. When the IAT sensor is cold, the sensor
resistance is high. When the air temperature increases,
the sensor resistance decreases. With high sensor
resistance, the ECM detects a high voltage on the
signal circuit. With lower sensor resistance, the ECM
detects a lower voltage on the signal circuit. If the ECM
detects an excessively low or high signal voltage, DTC
P0112 or P0113 will set.

Condition for Running the DTC

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

• The engine run time is longer than 3 minutes.

(DTC P0113)

Condition for Setting the DTC

• The ECM detects that the IAT sensor signal

voltage is less than 0.1 volts for 3 seconds. (DTC
P0112)

• The ECM detects that the IAT sensor signal

voltage is more than 4.75 volts for 3 seconds.
(DTC P0113)

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 uses an IAT substitution of default value.

• The ECM limits fuel injection quantity.

• The ECM inhibits EGR control.

• 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.

• Use the Temperature vs. Resistance table to test

the IAT sensor at various temperature levels to
evaluate the possibility of a skewed sensor. A
skewed sensor could result in poor driveability
concerns.

Schematic Reference: Engine Controls Schematics

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

Circuit/ System Testing DTC P0112

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.

Observe the Intake Air Temperature (IAT)
Sensor parameter with a scan tool.

Is the IAT Sensor parameter less than the specified
value?

0.1 volts

Go to Step 3

Go to Diagnostic 

Aids

3

1.

Turn OFF the ignition.

2.

Disconnect the mass air flow/ intake air
temperature (MAF/ IAT) sensor harness
connector.

3.

Turn ON the ignition, with the engine OFF.

Is the IAT Sensor parameter more than the
specified value?

4.7 volts

Go to Step 5

Go to Step 4