Isuzu KB P190. Manual - part 433

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-115

11

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 26 and 27 of E-90).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 13

12

Replace the ECT sensor. Refer to ECT Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 14

—

13

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

Did you complete the replacement?

—

Go to Step 14

—

14

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 15

15

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-116   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0122 or P0123 (Flash Code 43)

Circuit Description

The intake throttle position sensor is installed on the
intake throttle valve body together with the control
solenoid. The intake throttle position sensor changes
output voltage according to intake throttle valve
position. The sensor has the following circuits.

• 5 volts reference circuit

• Low reference circuit

• Intake throttle position sensor signal circuit

The intake throttle position sensor provides a signal to
the ECM on the signal circuit, which is relative to the
position changes of the intake throttle valve. If the ECM
detects an excessively low or high signal voltage, DTC
P0122 or P0123 will set.

Condition for Running the DTC

• DTCs P0698 and P0699 are not set.

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects that the intake throttle position

sensor signal voltage is less than 0.1 volts. (DTC
P0122)

• The ECM detects that the intake throttle position

sensor signal voltage is less than 4.75 volts. (DTC
P0123)

Action Taken When the DTC Sets

• The ECM illuminates the MIL on the second

consecutive driving cycle when the diagnostic runs
and fails. Refer to DTC Type Definitions for Action
Taken When the DTC Sets - Type B. (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 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 B (Euro 4
Specification)

• Refer to DTC Type Definitions for Condition for

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

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 P0122

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 P0698 also set?

—

Go to DTC P0698

Go to Step 3

3

Observe the Intake Throttle Position Sensor
parameter with a scan tool.

Is the Intake Throttle Position Sensor parameter
less than the specified value?

0.1 volts

Go to Step 4

Go to Diagnostic 

Aids

4

1.

Turn OFF the ignition.

2.

Disconnect the intake throttle valve harness
connector.

3.

Connect a DMM between the 5 volts reference
circuit (pin 6 of E-38) and a known good
ground.

4.

Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

4.7 volts

Go to Step 5

Go to Step 6

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-117

5

Connect a 3-amp fused jumper wire between the 5
volts reference circuit and the signal circuit (pins 5
and 6 of E-38).

Is the Intake Throttle Position 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 36 of E-90) and the intake throttle
valve (pin 6 of E-38) for an open circuit for
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
57 of E-90) and the intake throttle valve (pin 5
of E-38) 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
intake throttle valve (pins 5 and 6 of E-38).

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 36 and 57 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 intake throttle valve. Refer to Intake
Throttle Valve 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-118   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Circuit/ System Testing DTC P0123

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 Intake Throttle Position Sensor
parameter with a scan tool.

Is the Intake Throttle Position Sensor parameter
more than the specified valve?

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 intake throttle valve harness
connector.

3.

Turn ON the ignition, with the engine OFF.

Is the Intake Throttle Position 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 intake throttle valve harness
connector.

3.

Turn ON the ignition, with the engine OFF.

Is the Intake Throttle Position 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 3 of E-38) and battery voltage.

Does the test lamp illuminate?

—

Go to Step 9

Go to Step 8

7

Important: The intake throttle position sensor may
be damaged if the sensor signal circuit is shorted to
a voltage source.

1.

Test the signal circuit between the ECM (pin
57 of E-90) and the intake throttle valve (pin 5
of E-38) 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 35 of E-90) and the intake throttle
valve (pin 3 of E-38) 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