ISUZU KB P190 2007 Workshop Repair Manual

6E-314 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Cruise Control System Check
Description
The cruise control system consists of the ECM, the
cruise main switch, set/ coast switch, resume/ accel.
switch and cancel switch. The cruise control keeps the
vehicle speed at a driver's set speed. When the cruise
main switch is turned ON, signal is provided to the
ECM and the cruise main indicator lamp on the switch
will light up. When the cruise set/ coast switch is turned
ON, the switch signal is provided to the ECM and the
vehicle speed is set. The vehicle speed is increased or
decreased if the set/ coast switch or the resume/ accel.
switch is turned ON. When the cruise cancel switch is
applied, the switch signal is provided to the ECM and
the cruise control system is inactive.
Condition for Running the Cruise Control • The vehicle speed is between approximately 40 km/h (24 MPH) to 175 km/h (105 MPH).
• The engine speed is less than 4500 PRM.
• The cruise main switch is ON.
1. Function of "SET"
If the set/ coast switch is pressed and released while
condition for running the cruise control are satisfied, the
ECM memorize and maintain the vehicle speed at that
time.
2. Function of "COAST"
If the set/ coast switch is pressed while the cruise
control system is operating, the vehicle speed is
decreased. Then, when the set/ coast switch is
released, the vehicle will maintain the vehicle speed at
that time.
3. Function of "RESUME"
If the resume/ accel. switch is applied while the cruise
control system is operating and the ECM memorizes
the vehicle speed, the vehicle speed is returned to the
vehicle speed memorized by the ECM.
4. Function of "ACCEL"
If the resume/ accel. switch is applied while the cruise
control system is operating, the vehicle speed is
increased. Then, when the resume/ accel. switch is
released, the vehicle will maintain the vehicle speed at
that time.
5. Function of "TAP UP"
If the resume/ accel. switch is tapped (momentarily
applied) while the cruise control system is operating,
the vehicle speed is increased 1 km/h (0.6 MPH) at a
time. 6. Function of "TAP DOWN"
If the set/ coast switch is tapped while the cruise control
system is operating, the vehicle speed is decreased 1
km/h (0.6 MPH).
7. Function of Temporary Acceleration
If the accelerator pedal is pressed while the cruise
control system is operating, the vehicle speed is
increased.
8. Function of Temporary Cancellation
The cruise control is canceled temporarily if any of the
following condition is met:
• The cruise cancel switch is applied.
• The brake pedal is depressed.
• The clutch pedal is depressed (M/T).
• The selector lever position is not D, 3, 2 or L (A/T).
• The cruise set/ coast switch and resume/ accel. switch are ON at the same time.
• The actual vehicle speed becomes less than approximately 35 km/h (22 MPH).
• The actual vehicle speed is more than 40 km/h (24 MPH) over the set speed, or more than 10 km/h (6
MPH) over the set speed for longer than 3
minutes.
• The actual vehicle speed is more than 70 km/h (42 MPH) below the set speed, or more than 10 km/h
(6 MPH) below the set speed for 3 minutes.
By applying the resume/ accel. switch, the vehicle
speed is returned to the vehicle speed memorized by
the ECM (resume function) if within the condition for
running the cruise control are satisfied.
9. Function of Complete Cancellation
The cruise control is canceled completely if any of the
following condition is met:
• The cruise main switch is OFF.
• The ignition switch is OFF.
• The vehicle is once stopped.
• The DTCs relating to the cruise control system inhibits are set.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Cruise Control System Check (1 of 2)
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

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-315
21. 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

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6E-316 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
121. 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
—
151. 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

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-317
191. 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
—
26Repair or replace the combination switch.
Did you complete the repair or replacement? —
Go to Step 28—
27Important
: 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

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6E-318 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Circuit/ System Testing Cruise Control System Check (2 of 2)
28Reconnect 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

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-319
71. Remove the Meter (10A) fuse that supplies
voltage to the IP cluster.
2. Turn ON the ignition, with the engine OFF.
3. Measure the voltage from the cruise set lamp control circuit in the ECM harness connector
(pin 49 of C-58) to a good ground.
Is the voltage less than the specified value? 1 volt
Go to Step 8 Go to Step 10
8 1. Turn OFF the ignition.
2. Reinstall the Meter (10A) fuse.
3. Turn ON the ignition, with the engine OFF.
4. Connect a 3-amp fused jumper wire between the cruise set lamp control circuit of the ECM
harness connector (pin 49 of C-58) and a
known good ground.
Is the cruise main lamp illuminated? —
Go to Step 12 Go to Step 9
9 1. Test the control circuit between the ECM (pin
49 of C-58) and the IP cluster (pin 23 of B-23)
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
10 Repair the short to battery or ignition voltage on the
control circuit between the ECM (pin 49 of C-58)
and the IP cluster (pin 23 of B-23).
Did you complete the action? —
Go to Step 15
—
111. Inspect for an intermittent and for a poor
connection at the harness connector of the IP
cluster (pins 23 of B-23).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 13
12 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for poor connections on the cruise main or set lamp
control circuit at the harness connector of the
ECM (pin 49 or 50 of C-58).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 14
13 Repair or replace the IP cluster.
Did you complete the repair or replacement? —
Go to Step 15
—
14Important
: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 15
—
15Reconnect all previously disconnected
components, fuse or harness connector(s).
Is the action complete? —
Go to 1 of 2 Step 2
—
Step Action Value(s)Yes No

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6E-320 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Turbocharger Control System Check
Description
The position of the turbocharger nozzle is controlled by
the ECM. The ECM utilizes a turbocharger nozzle
control solenoid valve and a boost pressure sensor to
control the turbocharger nozzles. When the engine is
not under load, the turbocharger nozzles are in an open
position, or no boost condition. When the engine is
under load, the ECM commands the control solenoid
valve to close the turbocharger nozzles, thus
increasing the boost. The ECM will vary the boost
dependant upon the load requirements of the engine.
The ECM uses a pulse width modulation (PWM) on the
control circuit to open and control the solenoid valve. Notice:
• This Circuit/ System Testing is only applicable to high output engine.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Turbocharger Control System Check
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 P0045, P0107, P0108, P0112, P0113,
P0116, P0117, P0118, P0234, P0299, P0638,
P0698, P0699, P1196, P1197, P1198, P2227,
P2228 or P2229 also set? —
Go to Applicable DTC Go to Step 3

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-321
31. Inspect the following conditions:
• Air leakage around the boost pressuresensor objects that block the sensor hole.
• Air leaking around any of the air induction tubing between the turbocharger and
intake manifold. Check for damaged
components and for loose clamps.
• Misrouted, disconnected or kinked turbocharger nozzle control actuator
vacuum hoses. Refer to Vacuum Hose
Routing Diagram in this section for
correct routing.
• Turbine shaft binding causing lower turbocharger spinning speeds. Refer to
the Turbocharger in engine mechanical
section for diagnosis.
• Turbocharger nozzle control actuator for a stuck condition or slow movement.
Refer to Turbocharger in engine
mechanical section for testing.
• Intake throttle valve sticking. Perform the Intake Throttle Solenoid Control with a
scan tool.
• Restricted air cleaner element, restricted or collapsed air tubing between the air
cleaner and the boost pressure sensor.
• Oil in the air induction tubing causing an incorrect boost pressure sensor signal.
When there is adhesion of oil inside of
tubing, intercooler or turbocharger it
needs to be wiped off.
2. Repair the condition as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 4
4 1. Place the transmission in Neutral and set the
parking brake.
2. Accelerate the engine between idle and W.O.T. (accelerator pedal full travel) many
times while observing the Desired Boost
Pressure and Boost Pressure parameter with
a scan tool.
3. Drive the vehicle that the engine speed is more than 2000 RPM and the Calculated
Engine Load parameter reaches at least 50%
for longer than 10 seconds (such as
acceleration on ramp) while comparing the
Boost Pressure to the Desired Boost
Pressure.
Does the Boost Pressure parameter follow within
the specified value? ±
20 kPa ( ±3
psi)
System OK Go to Step 5
Step
Action Value(s)Yes No

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6E-322 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
51. Turn OFF the ignition.
2. Disconnect the vacuum hose from the turbocharger nozzle control actuator
diaphragm.
3. Connect a hand-held vacuum pump (5-8840- 0279-0/ J-23738-A) to the disconnected
vacuum hose.
4. Start the engine and let idle.
5. Perform the Turbocharger Solenoid Control with a scan tool.
6. Command the solenoid valve Increase and Decrease while observing the vacuum pump.
Does the hand-held vacuum pump reading more
than 50 cmHg (20 inHg) when commanded
maximum Increase and ZERO range when
commanded minimum Decrease? —
Go to Step 8 Go to Step 6
6 1. Inspect the following conditions:
• Misrouted, disconnected, kinked orplugged turbocharger nozzle actuator
control vacuum hose.
• Misrouted, disconnected, kinked or plugged solenoid valve ventilation hose.
• Misrouted, disconnected, kinked or plugged vacuum source hose or pipe.
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 7
7 Replace the turbocharger nozzle control solenoid
valve.
Did you complete the replacement? —
Go to Step 8
—
81. Reconnect all previously disconnected
components or harness connector(s).
2. Clear the DTCs with a scan tool if set.
3. Turn OFF the ignition for 30 seconds.
Did you complete the action? —
Go to Step 2
—
Step Action Value(s)Yes No

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-323
Symptoms - Engine Controls
Symptoms - Engine Controls
Important Preliminary Inspections Before Starting
Perform Diagnostic System Check - Engine Controls
before using the symptom tables, and verify that all of
the following are true:
• The ECM and malfunction indicator lamp (MIL)/ service vehicle soon (SVS) lamp are operating
correctly.
• The scan tool data is within the normal operating range. Refer to Scan Tool Data List in this section.
• Verify the customer concern and locate the correct symptom in the table of contents. Inspect the items
indicated under that symptom.
Visual and Physical Inspection
Several of the symptom procedures ask for careful
visual and physical inspection. This step is extremely
important. The visual and physical inspection can lead
to correcting a problem without further inspections, and
can save valuable time. Ensure that:
• The ECM grounds are clean, tight, and in their proper location.
• The vacuum hoses are not split or kinked, and properly connected. Inspect thoroughly for any
type of leak or restriction.
• The air intake ducts are not collapsed or damaged.
• The exhaust pipes are not collapsed or damaged.
• The engine harness wiring and terminals are properly connected and are not pinched or cut.
Intermittent
Important: Inspect for improper installation of electrical
components if an intermittent condition exists. Inspect
for aftermarket add-on electrical equipment devices,
lights, and cellular phones. Verify that no aftermarket
equipment is connected to the controller area network
(CAN) or other serial data circuit.
Important: The problem may or may not turn ON the
MIL/ SVS lamp or store a DTC. Faulty electrical
connections or wiring cause most intermittent
problems. Perform a careful visual and physical
inspection of the suspect connectors for the following
conditions:
• Improperly mated connector halves
• Terminals that are not seated
• Terminals that are damaged or improperly formed Reform or replace connector terminals in the problem
circuit in order to ensure proper contact tension.
Remove the terminal from the connector body in order
to inspect for poor terminal wire connection.
Road test the vehicle with the DMM connected to the
suspected circuit. An abnormal reading that occurs
when the malfunction occurs is a good indication that
there is a malfunction in the circuit being monitored.
Use the scan tool in order to help detect intermittent
conditions. Useful features of the Tech 2 scan tool
include the following:
• Trigger the Snapshot feature in order to capture and store engine parameters when the malfunction
occurs. Review this stored information in order to
see the specific running conditions that caused the
malfunction.
• Freeze Frame/ Failure Record can also aid in locating an intermittent condition. Review and
capture the information in the Freeze Frame/
Failure Record associated with the intermittent
DTC being diagnosed. Drive the vehicle within the
conditions that were present when the DTC
originally set.
• Use the Plot Function on the scan tool in order to plot selected data parameters. Review this stored
information to aid in locating an intermittent
problem. Refer to the scan tool Users Guide for
more information.
Use the data recording module (DRM) in order to help
detect intermittent conditions. The DRM has ability to
store engine log data when an event of DTC. Maximum
three log data can be stored in the DRM memory. If
more than maximum number of storage is set, oldest
log data is overwritten. However, if same DTC is set
within eight hours that DTC is not stored in the DRM
memory.
The manual trigger function is to store the log data by
an arbitrary operation of the driver when an event of
wrong vehicle performance that is instead of an event
of DTC. If the driver presses and releases the manual
trigger switch once, that time becomes a trigger and
one log data before and behind the trigger is stored in
the DRM memory. When there is a space in the DRM
memory, log data is stored in that space. However,
when more than maximum number of storage is set,
oldest log data is overwritten.
Refer to the DRM Users Guide for more information.
Important: If the intermittent condition exists as a start
and then stall, test for DTCs relating to the vehicle theft
deterrent system. Test for improper installation of
electrical options such as lights, cellular phones, etc..
Any of the following may cause an intermittent MIL/
SVS lamp with no stored DTC:
• The ECM grounds are loose or dirty. Refer to Engine Controls Schematics.

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