Isuzu KB P190. Manual - part 483

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-315

2

1.

Drive the vehicle at 50 km/h (30 MPH) on a
flat level road.

2.

Press and release the cruise main switch.

3.

Press and release the cruise set/ coast switch.

4.

Verify the 50 km/h (30 MPH) vehicle speed is
maintained.

5.

Tap the cruise set/ coast.

Did the vehicle maintain the set speed of 50 km/h
(30 MPH), and then decrease by 1 km/h (0.6 MPH)
each time the switch was tapped?

—

Go to Step 3

Go to Step 7

3

Tap (momentarily apply) the cruise resume/ accel.
switch 10 times.

Does the vehicle speed increase by 1 km/h (0.6
MPH) each time the switch was tapped
(momentarily applied)?

—

Go to Step 4

Go to Step 10

4

Are the cruise main and cruise set lamps
illuminated while in cruise control?

—

Go to Step 5

Go to 2 of 2 Step 1

5

Apply the cruise cancel switch

Does the cruise control cancel?

—

Go to Step 6

Go to Step 11

6

1.

Reenter the cruise control.

2.

Depress and release the brake pedal.

Does the cruise control cancel?

—

System OK

Refer to DTC P0571 

for brake switch 

diagnosis

7

1.

Park the vehicle.

2.

Install a scan tool.

3.

Monitor the DTC Information with a scan tool.

Are any DTCs set in which the 

“Action Taken When

the DTC Sets”

 under that particular code states,

“The ECM inhibits cruise control”?

—

Refer to Applicable 

DTC

Go to Step 8

8

Observe the Cruise Main Switch parameter with a
scan tool.

Does the scan tool indicate ON when the switch is
pushed and OFF when the switch is released?

—

Go to Step 9

Go to Step 12

9

Observe the Cruise Set/ Coast Switch parameter
with a scan tool.

Does the scan tool indicate ON when the switch is
pushed and OFF when the switch is released?

—

Retest the cruise 

control. Refer to 

Condition for 

Running the Cruise 

Control

Go to Step 17

10

Observe the Cruise Resume/ Accel. Switch
parameter with a scan tool.

Does the scan tool indicate ON when the switch is
applied and OFF when the switch is released?

—

Go to Intermittent 

Conditions

Go to Step 19

11

Observe the Cruise Cancel Switch parameter with
a scan tool.

Does the scan tool indicate OFF when the switch is
applied and ON when the switch is released?

—

Go to Intermittent 

Conditions

Go to Step 23

Step

Action

Value(s)

Yes

No

6E-316   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

12

1.

Turn OFF the ignition.

2.

Disconnect the cruise main switch harness
connector.  (Remove the switch from the IP
bezel as necessary)

3.

Turn ON the ignition, with the engine OFF.

4.

Connect a test lamp between the ignition
voltage feed circuit of the cruise main switch
harness (pin 4 of B-56) and a known good
ground.

Does the test lamp illuminate?

—

Go to Step 13

Go to Step 14

13

Observe the Cruise Main Switch parameter with a
scan tool while momentarily jumping 3-amp fused
jumper wire across the cruise main switch harness
connector between pins 3 and 4 of the B-67.

Does the scan tool indicate ON when the circuit is
jumpered and OFF when the circuit is not
jumpered?

—

Go to Step 16

Go to Step 15

14

Repair the open circuit or high resistance between
the Engine (10A) fuse and the cruise main switch
(pin 4 of B-67).

Did you complete the repair?

—

Go to Step 28

—

15

1.

Test the signal circuit between the ECM (pin
14 of C-58) and the cruise main switch (pin 3
of B-67) for an open circuit or high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 22

16

1.

Inspect for an intermittent and for poor
connections at the harness connector of the
cruise main switch (pins 3 and 4 of B-67).

2.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 25

17

1.

Turn OFF the ignition.

2.

Disconnect the combination switch harness
connector (B-59). (Remove the IP cluster
lower cover as necessary)

3.

Turn ON the ignition, with the engine OFF.

4.

Observe the Cruise Set Switch parameter with
a scan tool while momentarily jumping 3-amp
fused jumper wire across the combination
switch harness connector (male side) between
pins 11 and 12 of B-59.

Does the scan tool indicate ON when the circuit is
jumpered and OFF when the circuit is not
jumpered?

—

Go to Step 21

Go to Step 18

18

1.

Test the signal circuit between the ECM (pin
30 of C-58) and the combination switch (pin
12 of B-59) for an open circuit or high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 22

Step

Action

Value(s)

Yes

No

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-317

19

1.

Turn OFF the ignition.

2.

Disconnect the combination switch harness
connector (B-59). (Remove the IP cluster
lower cover as necessary)

3.

Turn ON the ignition, with the engine OFF.

4.

Observe the Cruise Resume Switch
parameter with a scan tool while momentarily
jumping 3-amp fused jumper wire across the
combination switch harness connector (male
side) between pins 9 and 11 of B-59.

Does the scan tool indicate ON when the circuit is
jumpered and OFF when the circuit is not
jumpered?

—

Go to Step 21

Go to Step 20

20

1.

Test the signal circuit between the ECM (pin
29 of C-58) and the combination switch (pin 9
of B-59) for an open circuit or high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 22

21

1.

Inspect for an intermittent and for poor
connections at the harness connector of the
combination switch (pins 9 or 12 of B-59).

2.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 26

22

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 14, 29 or 30 of C-58).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 27

23

1.

Turn OFF the ignition.

2.

Disconnect the combination switch harness
connector (B-59).

3.

Turn ON the ignition, with the engine OFF.

Does the Cruise Cancel Switch indicate OFF?

—

Go to Step 26

Go to Step 24

24

1.

Test the signal circuit between the ECM (pin
13 of C-58) and the combination switch (pin
10 of B-59) for a short to battery or ignition
voltage.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 28

Go to Step 27

25

Repair or replace the cruise main switch.

Did you complete the repair or replacement?

—

Go to Step 28

—

26

Repair or replace the combination switch.

Did you complete the repair or replacement?

—

Go to Step 28

—

27

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

Did you complete the replacement?

—

Go to Step 28

—

Step

Action

Value(s)

Yes

No

6E-318   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Circuit/ System Testing Cruise Control System Check (2 of 2)

28

Reconnect all previously disconnected
components, fuse or harness connector(s).

Did you complete the action?

—

Go to Step 2

—

Step

Action

Value(s)

Yes

No

1

1.

Verify whether the instrument panel (IP)
cluster is operational.

2.

Install a scan tool.

3.

Perform the Lamp Control with a scan tool.

4.

Command the lamp ON and OFF with a scan
tool.

5.

Perform the Cruise Set Lamp Control with a
scan tool.

6.

Command the lamp ON and OFF with a scan
tool.

Are both lamps ON and OFF when commanded
with a scan tool?

—

Go to Intermittent 

Conditions

Go to Step 2

2

Is the cruise main lamp inoperative?

—

Go to Step 3

Go to Step 7

3

1.

Remove the Meter (10A) fuse that supplies
voltage to the IP cluster (Euro 4 specification)
or the Engine (10A) fuse that supplies voltage
to the cruise main switch (Except Euro 4
specification).

2.

Turn ON the ignition, with the engine OFF.

3.

Measure the voltage from the cruise main
lamp control circuit in the ECM harness
connector (pin 50 of C-58) to a good ground.

Is the voltage less than the specified value?

1 volt

Go to Step 4

Go to Step 6

4

1.

Turn OFF the ignition.

2.

Reinstall the Meter (10A) or Engine (10A)
fuse.

3.

Turn ON the ignition, with the engine OFF.

4.

Connect a 3-amp fused jumper wire between
the cruise main lamp control circuit of the
ECM harness connector (pin 50 of C-58) and
a known good ground.

Is the cruise main lamp illuminated?

—

Go to Step 12

Go to Step 5

5

1.

Test the control circuit between the ECM (pin
50 of C-58) and the IP cluster (pin 2 of B-23)
or the cruise main switch (pin 6 of B-67) for an
open circuit or high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 11

6

Repair the short to battery or ignition voltage on the
control circuit between the ECM (pin 50 of C-58)
and the IP cluster (pin 2 of B-23) or the cruise main
switch (pin 6 of B-67).

Did you complete the repair?

—

Go to Step 15

—

Step

Action

Value(s)

Yes

No