Isuzu KB P190. Manual - part 447

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-171

9

1.

Inspect for an intermittent and for a poor
connection at the harness connector of the
EGR valve (pin 2 of E-71).

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 30 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 EGR valve. Refer to EGR Valve
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-172   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0500 (Flash Code 25)

Circuit Description

The vehicle speed sensor (VSS) is used by the ECM
and speedometer, which generates a speed signal from
the transmission output shaft rotational speed or
transfer output shaft rotational speed. The sensor has
the following circuits.

• Ignition voltage circuit

• Low reference circuit

• VSS signal circuit

The VSS uses a hall effect element. It interacts with the
magnetic field created by the rotating magnet and
outputs square wave pulse signal. The ECM calculates
the vehicle speed by the VSS. If the 2WD fitted with
Jatco automatic transmission, VSS signals are sent
from the TCM. If the ECM detects VSS signals are not
generated, this DTC will set.

Condition for Running the DTC

• The ignition voltage is more than 9 volts.

• The ignition switch is ON.

• The engine speed is more than 1000 RPM.

• The commanded fuel injection quantity is OFF

(accelerator pedal is not depressed).

Condition for Setting the DTC

• The ECM detects that the VSS signals are not

generated for 5 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 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.

• Electromagnetic interference in the VSS circuits

may set this DTC.

Notice:

• If this DTC set, the Vehicle Speed parameter on

the scan tool will display 3 km/h (2 MPH).

Schematic Reference: Engine Controls Schematics

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

Circuit/ System Testing DTC P0500 (2WD fitted with Jatco A/T)

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.

Monitor the DTC Information with a scan tool.

Is DTC P0219 also set?

—

Go to DTC P0219

Go to Step 3

3

Monitor the transmission DTC Information with a
scan tool.

Is DTC P0722 set?

—

Go to P0722 in 

Automatic 

Transmission 

Section

Go to Step 4

4

Drive the vehicle while observing the Vehicle
Speed parameter with a scan tool.

Does the scan tool indicate correct vehicle speed?

—

Go to Diagnostic 

Aids

Go to Step 5

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-173

5

1.

Turn OFF the ignition.

2.

Disconnect the TCM harness connector.

3.

Turn ON the ignition, with the engine OFF.

4.

Intermittently jump the signal circuit (pin 10 of
C-94) with a test lamp that is connected to a
known good ground while observing the
Vehicle Speed parameter with a scan tool.

Does the scan tool indicate any vehicle speed
when the circuit is intermittently pulled to ground?

—

Go to Step 7

Go to Step 6

6

1.

Test the signal circuit between the ECM (62 of
C-58) and the TCM (10 of C-94) for the
following conditions:

• An open circuit

• A short to ground

• A short to battery or ignition voltage

• High resistance

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 8

7

1.

Turn OFF the ignition.

2.

Inspect for an intermittent and for a poor
connection at the harness connector of the
TCM (pin 10 of C-94).

3.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 9

8

1.

Turn OFF the ignition.

2.

Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 62 of C-58).

3.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 10

9

Important: Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.

Did you complete the replacement?

—

Go to Step 11

—

10

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

Did you complete the replacement?

—

Go to Step 11

—

11

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.

Drive the vehicle while observing the Vehicle
Speed parameter with a scan tool.

Does the scan tool indicate correct vehicle speed?

—

Go to Step 12

Go to Step 3

12

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-174   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Circuit/ System Testing DTC P0500 (except 2WD fitted with Jatco A/T)

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.

Monitor the DTC Information with a scan tool.

Is DTC P0219 also set?

—

Go to DTC P0219

Go to Step 3

3

Drive the vehicle while observing the Vehicle
Speed parameter with a scan tool.

Does the scan tool indicate correct vehicle speed?

—

Go to Diagnostic 

Aids

Go to Step 4

4

1.

Turn OFF the ignition.

2.

Disconnect the vehicle speed sensor (VSS)
harness connector.

3.

Turn ON the ignition, with the engine OFF.

4.

Connect a test lamp between the ignition
voltage feed circuit (pin 1 of E-44) and a
known good ground.

Does the test lamp illuminate?

—

Go to Step 5

Go to Step 7

5

Intermittently jump the signal circuit (pin 3 of E-44)
with a test lamp that is connected to a known good
ground while observing the Vehicle Speed
parameter with a scan tool.

Does the scan tool indicate any vehicle speed
when the circuit is intermittently pulled to ground?

—

Go to Step 6

Go to Step 9

6

Connect a test lamp between the voltage feed
circuit and the low reference circuit (pins 1 and 2 of
E-44).

Does the test lamp illuminate?

—

Go to Step 10

Go to Step 8

7

Repair the open circuit or high resistance between
the Meter (10A) fuse and the VSS (pin 1 of E-44).
Check the Meter (10A) fuse first.

Did you complete the repair?

—

Go to Step 15

—

8

Repair the open circuit or high resistance on the
low reference circuit between the VSS (pin 2 of E-
44) and ground terminal (E-10). Clean or tighten
ground as necessary.

Did you complete the repair?

—

Go to Step 15

—

9

1.

Test the signal circuit between the ECM (pin
62 of C-58) and the VSS (pin 3 of E-44), then
between the instrument panel (IP) cluster (pin
8 of B-23) and the VSS (pin 3 of E-44) for the
following conditions:

• An open circuit

• A short to ground

• A short to the low reference circuit

• A short to battery or ignition voltage

• High resistance

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 11