Isuzu KB P190. Manual — part 1398

Cruise Control – HFV6

Page 8C–14

2.4

Cruise Control Inoperative /
Malfunctioning

Circuit Description

When the ON-OFF button is pressed, 12 V is applied to the Powertrain Interface Module (PIM) connector B – 97 pin 14.
This enables and disables cruise control operation.

Pressing the cruise control switch assembly to SET–COAST button activates the cruise control at a desired speed above
40 km/h. This provides a 12 V signal to the PIM through connector B – 97 pin 15.

Pressing and holding the cruise control switch to SET–COAST provides a 12 V signal to the PIM at connector B – 97
pin 15. Turning the cruise control switch to RES–ACC will apply a 12 V signal to the PIM at connector B – 97 pin 16.
Turning the cruise control switch to CANCEL will apply a 12 V signal to the PIM at connector B – 97 pin 17.

Pressing the brake pedal opens the cruise Initial Brake Apply Signal circuit thus removing the supply voltage from the
ECM connector C – 56 pin 46. Simultaneously, the stop lamp circuit will close (normally open) and supply 12 V to the
ECM at connector C – 56 pin 10. Both these signals must be present so as to ensure the safe operation of the vehicle’s
cruise cancel function.

Manual Vehicles Only

Pressing the clutch pedal opens the cruise cancel circuit thus removing the supply voltage from the ECM at connector C
– 56 pin 53.

For detailed information refer to 3.4 Clutch Pedal Switch (Manual Only) in this Section.

Test Description

The following numbers refer to the step numbers in the diagnostic table:

4–7 Checks the cruise control switch and associated circuits are functioning correctly.

8–9 Checks the brake pedal switch assembly and associated circuit are functioning correctly.

10

Checks the clutch pedal switch assembly and associated circuits are functioning correctly.

11–21

Covers the testing and replacement of system components.

22–28

Checks for intermittent faults in associated circuits and connectors.

Diagnostic Table Notes

1

For all wiring harness fault diagnoses and repairs, refer to 2.3

Wiring Diagrams in this Section.

2

Tech 2 can display a stored history of which system parameter or input caused the cruise control to disengage.
This can aid diagnosis of intermittent faults.

Diagnostic Table

Step Action

Yes

No

1

Did you review the System Operation?

Go to Step 2

Go to 1.3

System

Operation

2

Did you read Diagnostic Systems Check ?

Go to Step 3

Go to Diagnostic

Systems Check

Cruise Control – HFV6

Page 8C–15

Step Action

Yes

No

3

Check the ignition supply circuits to the Stop Lamp Switch assembly
connector C – 44 pin 1 is serviceable using a multimeter set to
measure voltage, refer to 2.3

Wiring Diagrams in this Section

Is there a +12 volt signal present at connector C – 44 pin 1?

Go to Step 4

Replace the faulty

fusible link Main,

IG2 or Stop Light

fuse (refer to

Note 1).

If either of the

fusible links or fuse

blows again, repair

or replace the faulty

circuit (refer to

Note 1)

4

1

Connect Tech 2 to the DLC.

2

On Tech 2 select:
Body / Powertrain Interface Module / Diagnostic Data
Display.

3 Scroll

to

Cruise Main Switch.

4

While monitoring Tech 2, press the cruise control switch ON–
OFF button.

Does Tech 2 display the following:

•

Inactive and Active as the cruise control switch is pressed?

Go to Step 5

Go to Step 11

5

1 Scroll

to

Cruise Resume Switch.

2

While monitoring Tech 2, rotate the cruise control switch.

Does Tech 2 display the following:

•

Inactive when the cruise control switch is in the neutral
position?

•

Res / Acc when the cruise control switch is rotated to the RES–
ACC. Position?

Go to Step 6

Go to Step 12

6

1 Scroll

to

Cruise Set Switch.

2

While monitoring Tech 2, press the cruise control switch.

Does Tech 2 display the following:

•

Inactive when the cruise control switch is in the neutral
position?

•

Set / Coast when the cruise control switch is pressed to the
SET–COAST position?

Go to Step 7

Go to Step 13

7

1 Scroll

to

Cruise Cancel Switch.

2

While monitoring Tech 2, rotate the cruise control switch.

Does Tech 2 display the following:

•

Inactive when the cruise control switch is in the neutral
position?

•

Cancel when the cruise control switch is rotated to the CANCEL
position?

Go to Step 8

Go to Step 14

Cruise Control – HFV6

Page 8C–16

Step Action

Yes

No

8

1

Return to the Main Menu on Tech 2.

2

On Tech 2 select:
Engine / V6 Engine / Data Display / Cruise Control Data.

3 Scroll

to

Brake Lamp Switch.

4

While monitoring Tech 2, press and then release to the brake
pedal.

Does Tech 2 display the following:

•

Active as the brake pedal is pressed?

•

Inactive when the pedal is released?

Go to Step 9

Go to Step 15

9

1 Scroll

to

Initial Brake Apply Sig.

2

While monitoring Tech 2, press and then release to the brake
pedal.

Does Tech 2 display the following:

•

Inactive when the pedal is released?

•

Active as the brake pedal is pressed?

Go to Step 10

Go to Step 16

10

N O T E

This procedure is only required on vehicles fitted with
manual transmissions. If the vehicle is fitted with an
automatic transmission, go to Step 24.

1 Scroll

to

Cruise Control Active.

2

While monitoring Tech 2, press and then release to the clutch
pedal.

Does Tech 2 display the following:

•

Active when the pedal is released?

•

Inactive as the clutch pedal is pressed?

Go to Step 30

Go to Step 17

11 Test the cruise control main switch, refer to 3.1

Cruise Control

Main Switch

Is the cruise control switch serviceable?

Go to Step 22

Go to Step 18

12 Test the cruise control switch assembly, refer to 3.2

Cruise Control

Switch Assembly

Is the cruise control switch assembly serviceable?

Go to Step 23

Go to Step 18

13 Test the cruise control switch assembly, refer to 3.2

Cruise Control

Switch Assembly

Is the cruise control switch assembly serviceable?

Go to Step 24

Go to Step 18

14 Test the cruise control switch assembly, refer to 3.2

Cruise Control

Switch Assembly

Is the cruise control switch assembly serviceable?

Go to Step 25

Go to Step 18

15 Test the stop lamp switch assembly, refer to 3.3

Stop Lamp

Switch Assembly.

Is the stop lamp switch serviceable?

Go to Step 26

Go to Step 19

16 Test the stop lamp switch assembly, refer to 3.3

Stop Lamp

Switch Assembly.

Is the stop lamp switch serviceable?

Go to Step 26

Go to Step 20

Cruise Control – HFV6

Page 8C–17

Step Action

Yes

No

17

N O T E

This procedure is only required on vehicles fitted with
manual transmissions. If the vehicle is fitted with an
automatic transmission go to Step 26.

Test the clutch pedal switch, refer to

3.4 Clutch

Pedal

Switch.

Is the clutch pedal switch serviceable?

Go to Step 28

Go to Step 21

18 Replace the faulty cruise control switch assembly with a serviceable

item. To replace the switch assembly, refer to 8 B Cruise Control
System.

Go to Step 32

—

19 Replace the faulty stop lamp switch, refer to 3.3

Stop Lamp

Switch Assembly

Go to Step 32

—

20 Replace the faulty stop lamp switch, refer to 3.3

Stop Lamp

Switch Assembly

Go to Step 32

—

21 Replace the faulty clutch pedal switch, refer to

3.4

Clutch Pedal Switch

Go to Step 32

—

22 1

Disconnect the PIM connector B – 97.

2

Using a multimeter set to measure voltage, back probe between
the harness connector B – 97 pin 14 and a known ground.

3

With the aid of an assistant, monitor the voltage on the
multimeter and press and release the cruise control switch ON–
OFF button.

•

With the button in the rest position, the multimeter should
display 0 V.

•

With the button pressed, the multimeter should display
battery voltage.

Does the multimeter display as described?

Go to Step 30

Check for short to

ground or open

circuit.

Repair as required

(refer to Note 1).

Go to Step 32

23 1

Disconnect the PIM connector B – 97.

2

Using a multimeter set to measure voltage, back probe between
the harness connector B – 97 pin 16 and a known ground.

3

With the aid of an assistant, monitor the voltage on the
multimeter and rotate and release the cruise control switch to
RES–ACC position.

•

With the switch in the rest position, the multimeter should
display 0 V.

•

With the switch rotated, the multimeter should display
battery voltage.

Does the multimeter display as described?

Go to Step 30

Check for short to

ground or open

circuit on circuit.

Repair as required

(refer to Note 1).

Go to Step 32