Isuzu KB P190. Manual - part 473

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-275

15

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.

Fully depress and release the accelerator
pedal while observing the APP Sensor 3
parameter with the scan tool.

Does the scan tool indicate more than the specified
value during depressing or releasing the pedal?

4.8 volts

Go to Step 3

Go to Step 16

16

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-276   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P2138, P2139 or P2140 (Flash Code 124, 125 or 126)

Circuit Description

The accelerator pedal position (APP) sensor is
mounted on the accelerator pedal control assembly.
The sensor is made up of three individual sensors
within one housing. The APP sensor 1, APP sensor 2
and APP sensor 3 are potentiometer type sensors,
each with the following circuits.

• 5 volts reference circuit

• Low reference circuit

• Signal circuit

The APP sensor provides a signal to the ECM on the
signal circuits, which is relative to the position changes
of the accelerator pedal angle. The APP sensor 1
signal voltage is low at rest and increases as the pedal
is depressed. The APP sensor 2 and APP sensor 3
signal voltage is high at rest and decreases as the
pedal is depressed. If the ECM detects that each APP
sensor signal voltage is out of the correlation, DTC
P2138, P2139 or P2140 will set.

Condition for Running the DTC

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

• The APP sensor 1 signal voltage is between 0.15

to 4.85 volt. (DTC P2138 or P2139)

• The APP sensor 2 signal voltage is between 0.15

to 4.85 volt. (DTC P2138 or P2140)

• The APP sensor 3 signal voltage is between 1.20

to 4.85 volt. (DTC P2139 or P2140)

Condition for Setting the DTC

• The ECM detects that the APP sensor 1 and 2 are

more than 40% out of range of each other. (DTC
P2138)

• The ECM detects that the APP sensor 1 and 3 are

more than 40% out of range of each other. (DTC
P2139)

• The ECM detects that the APP sensor 2 and 3 are

more than 40% out of range of each other. (DTC
P2140)

Action Taken When the DTC Sets

• The ECM illuminates the SVS lamp when the

diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. (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 limits fuel injection quantity.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the SVS Lamp/ DTC - Type C. (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 P2138

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 P0642, P0643, P0652, P0653, P0698,
P0699, P2132 or P2133 also set?

—

Go to Applicable 

DTC

Go to Step 3

3

Fully depress and release the accelerator pedal
while observing the DTC Information with a scan
tool.

Does the DTC fail this ignition?

—

Go to Step 4

Go to Diagnostic 

Aids

4

Is DTC P2140 also set?

—

Go to Step 6

Go to Step 5

5

Is DTC P2139 also set?

—

Go to Step 7

Go to Step 8

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-277

6

1.

Test each accelerator pedal position (APP)
sensor 2 circuits between the ECM (pins 9, 10
and 25 of C-58) and the APP sensor (pins 3, 8
and 9 of C-40) for high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 7

7

1.

Test each APP sensor 1 circuits between the
ECM (pins 11, 12 and 27 of C-58) and the
APP sensor (pins 4, 5 and 10 of C-40) for high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 8

8

1.

Test each APP sensor 3 circuits between the
ECM (pins 7, 8 and 23 of C-58) and the APP
sensor (pins 1, 6 and 7 of C-40) for high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 9

9

1.

Turn OFF the ignition.

2.

Disconnect the APP sensor harness
connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the APP sensor (pins 1, 3, 4, 5,
6, 7, 8, 9 and 10 of C-40).

4.

Disconnect the ECM harness connector.

5.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 7, 8, 9, 10, 11, 12,
23, 25 and 27 of C-58).

6.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 10

10

1.

Test the APP sensor 1 and sensor 3 signal
circuit between the ECM (pins 8 and 12 of C-
58) and the APP sensor (pins 5 and 6 of C-40)
for a short circuit each other.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 11

11

Replace the APP sensor. Refer to APP Sensor
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.

Fully depress and release the accelerator
pedal while observing the DTC Information
with a scan tool.

Does the DTC fail this ignition?

—

Go to Step 13

Go to Step 15

Step

Action

Value(s)

Yes

No

6E-278   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Circuit/ System Testing DTC P2139

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.

Fully depress and release the accelerator
pedal while observing the DTC Information
with a scan tool.

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

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 P0642, P0643, P0652, P0653, P0698,
P0699, P2127 or P2128 also set?

—

Go to Applicable 

DTC

Go to Step 3

3

Fully depress and release the accelerator pedal
while observing the DTC Information with a scan
tool.

Does the DTC fail this ignition?

—

Go to Step 4

Go to Diagnostic 

Aids

4

Is DTC P2138 also set?

—

Go to DTC P2138

Go to Step 5

5

Is DTC P2140 also set?

—

Go to DTC P2140

Go to Step 6

6

1.

Test each accelerator pedal position (APP)
sensor 2 circuits between the ECM (pins 9, 10
and 25 of C-58) and the APP sensor (pins 3, 8
and 9 of C-40) for high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 7