2007 ISUZU KB P190 engine

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-57
Scan Tool Does Not Communicate with CAN Device
Circuit Description
The ECM, transmission control module (TCM) (AISIN
A/T only) and immobilizer control unit (ICU) all
communicate with the scan tool over the controller area
network (CAN) link. The ECM, TCM, ICU and the data
recording module (DRM) communicate with each other
over the same CAN link. If no immobilizer system is
installed, the instrument panel (IP) cluster has a CAN
terminating resistor instead of the ICU.
Diagnostic Aids
The following conditions will cause a loss of CAN serial
data communication between the TCM and ICU or
between the scan tool and any control module: • A CAN serial data circuit open
• A CAN serial data circuit shorted to ground
• A CAN serial data circuit shorted to voltage
• An internal condition within a module or connector on the CAN serial data circuit, that causes a short
to voltage or ground to the CAN serial data circuit
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Scan Tool Does Not Communicate with CAN Device
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 Important
: Make sure the CANdi module is not
malfunctioning. When functioning properly, the
CANdi module LED will be flashing. In the event of
a problem, the LED will be continually illuminated
or not illuminated.
1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Attempt to establish communication with the listed control modules.
•ECM
• Immobilizer Control Unit (ICU) (If so equipped)
• Transmission control module (TCM) (AISIN A/T only)
Does the scan tool communicate with any of the
listed control modules? —
Go to Step 3 Go to Step 7
3 Does the scan tool communicate with the ECM?
—
Go to Step 4 Go to Lost
Communication with
The Engine Control Module (ECM)
4 Notice:
If no AISIN automatic transmission is
installed, skip to Step 5.
Does the scan tool communicate with the TCM? —
Go to Step 5 Go to Diagnostic
System Check -
Transmission Controls
5 Notice:
If no immobilizer system is installed, skip to
Step 6.
Does the scan tool communicate with the ICU? —
Go to Step 6 Go to Diagnostic
System Check -
Immobilizer Controls
6 Test the CAN Low and High serial data circuit for an
intermittently short to ground or intermittently short
to voltage. Then, test the CAN Low and High serial
data circuit for an intermittently open (based on
which control module did not communicate) at the
connection in the circuit.
Did you find and correct the condition? —
Go to Step 19 System OK

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-58 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
71. Inspect for an intermittent, for poor
connections and for corrosion at the data link
connector (DLC) (pins 6 and 14 of B-58).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 19 Go to Step 8
8 Notice:
If no data recording module (DRM) is
installed, skip to Step 9.
1. Turn OFF the ignition.
2. Disconnect the DRM C-139 harness connector.
3. Turn ON the ignition, with the engine OFF.
4. Attempt to communicate with the ECM, TCM and ICU.
Does the scan tool communicate with the ECM,
TCM and ICU? —
Go to Step 14 Go to Step 9
9 1. Turn OFF the ignition.
2. Reconnect the DRM harness connector if disconnected.
3. Disconnect the ECM J1 (E-90) and J2 (C-58) harness connectors.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to communicate with the TCM and ICU.
Does the scan tool communicate with the TCM and
ICU? —
Go to Step 15 Go to Step 10
10 Notice:
If no AISIN automatic transmission is
installed, skip to Step 11.
1. Turn OFF the ignition.
2. Reconnect the ECM J1 (E-90) and J2 (C-58) harness connectors.
3. Disconnect the TCM C-94 and C-95 harness connectors.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to communicate with the ECM and ICU.
Does the scan tool communicate with the ECM and
ICU? —
Go to Step 16 Go to Step 11
11 Notice:
If no immobilizer system is installed, skip to
St ep 1 2.
1. Turn OFF the ignition.
2. Reconnect the ECM J1 (E-90) and J2 (C-58) harness connectors if disconnected.
3. Reconnect the TCM C-94 and C-95 harness connectors if disconnected.
4. Disconnect the ICU B-68 harness connector.
5. Turn ON the ignition, with the engine OFF.
6. Attempt to communicate with the ECM and TCM.
Does the scan tool communicate with the ECM and
TCM? —
Go to Step 17 Go to Step 13
Step
Action Value(s)Yes No

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-59
121. Turn OFF the ignition.
2. Reconnect the ECM J1 (E-90) and J2 (C-58) harness connectors if disconnected.
3. Reconnect the TCM C-94 and C-95 harness connectors if disconnected.
4. Disconnect the instrument panel (IP) cluster B-23 and B-24 harness connector.
5. Turn ON the ignition, with the engine OFF.
6. Attempt to communicate with the ECM and TCM.
Does the scan tool communicate with the ECM and
TCM? —
Go to Step 18 Go to Step 13
13 Repair the open circuit, short to ground or short to
voltage on the CAN Low or High serial data circuit
between the DLC and ECM, TCM, ICU, DRM or IP
cluster.
Did you complete the repair? —
Go to Step 19
—
14Replace the DRM. Refer to DRM Replacement.
Did you complete the replacement? —
Go to Step 19—
15Important
: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 19
—
16Important
: Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.
Did you complete the replacement? —
Go to Step 19
—
17Important
: Replacement ICU must be
programmed.
Replace the ICU. Refer to ICU Replacement.
Did you complete the replacement? —
Go to Step 19
—
18Replace the IP cluster. Refer to IP Cluster
Replacement.
Did you complete the replacement? —
Go to Step 19
—
19Attempt to establish communication with the ECM,
TCM and ICU.
Does the scan tool communicate with the ECM,
TCM and ICU? —
System OK Go to Step 2
Step
Action Value(s)Yes No

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-60 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Lost Communication with The Engine Control Module (ECM)
Circuit Description
The ECM, transmission control module (TCM) (AISIN
A/T only) and immobilizer control unit (ICU) all
communicate with the scan tool over the controller area
network (CAN) link. The ECM, TCM, ICU and the data
recording module (DRM) communicate with each other
over the same CAN link. If no immobilizer system is
installed, the instrument panel (IP) cluster has a CAN
terminating resistor instead of the ICU. Schematic Reference:
Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Lost Communication with The Engine Control Module (ECM)
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 Attempt to establish communication with the ECM.
Does the scan tool communicate with the ECM? —Go to Intermittent
Conditions Go to Step 3
3 Check the ECM C-58 and E-90 connectors for poor
connections.
Did you find and correct the condition? —
Go to Step 16 Go to Step 4
4 1. Check the ECM (40A) slow blow fuse, ECM
(B) (10A) fuse and Engine (10A) fuse.
Replace and retest if open. If any fuse
continues to open, repair the short to ground
on each circuit fed by that fuse.
2. Turn OFF the ignition.
3. Disconnect the ECM C-58 harness connector.
4. Turn ON the ignition, with the engine OFF.
5. Connect a test lamp to ground and check for voltage at the ignition voltage supply circuit at
the ECM (pin 72 of C-58).
Does the test lamp illuminate? —
Go to Step 5 Go to Step 13
5 1. Turn OFF the ignition.
2. Disconnect the scan tool from the data link connector (DLC) if connected.
3. Measure the resistance across the CAN Low and High circuits by probing the DLC (pins 6
and 14 of B-58).
Is the resistance within the specified value (parallel
resistance of the 120 Ω resistor in the ECM and the
120 Ω resistor in the ICU or IP cluster should be
60 Ω)? 50 to 70
Ω
Go to Step 7 Go to Step 6
6 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 66 and 67 of C-
58).
4. Test for high resistance on each circuit.
5. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 15

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-61
71. Check ECM ground for corrosion and
tightness.
2. Clean or tighten grounds as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 8
8 1. Turn OFF the ignition.
2. Reconnect the ECM harness connector if disconnected.
3. Replace the ECM main relay with the heater relay or replace with a known good relay.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to establish communication with the ECM.
Does the scan tool communicate with the ECM? —
Go to Step 14 Go to Step 9
9 1. Turn OFF the ignition.
2. Remove the ECM main relay.
3. Turn ON the ignition, with the engine OFF.
4. Using a test lamp, check for both voltage supply circuits to the ECM main relay (pins 4
and 5 of X-12).
5. Repair the open circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 10
10 1. Reinstall the ECM main relay.
2. Turn the ignition ON and OFF while listening of feeling for the ECM main relay click. Wait 7
seconds between transitions.
Does the ECM main relay click when the ignition
switch is turned ON or OFF? —
Go to Step 12 Go to Step 11
11 Repair the ECM main relay ground circuit between
the ECM main relay (pin 2 of X-12) and engine
room ground terminal (C-36) for the following
conditions: •An open circuit
• High resistance or a poor connection at the
ECM main relay or ground terminal
Did you complete the repair? —
Go to Step 16
—
121. Test the battery voltage circuit between the
ECM (pin 73 of C-58) and the ECM main relay
(pin 1 of X-12) for the following conditions:
• An open circuit
• High resistance or a poor connection at ECM or ECM main relay
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 15
13 Repair the open in the ignition voltage circuit to the
ECM.
Did you complete the repair? —
Go to Step 16
—
14Replace the ECM main relay.
Did you complete the replacement? —
Go to Step 16—
Step Action Value(s)Yes No

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-62 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
15Important
: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 16
—
161. Turn OFF the ignition.
2. Reconnect all previously disconnected fuse, relay or harness connector(s).
3. Turn ON the ignition, with the engine OFF.
4. Attempt to establish communication with the ECM.
Does the scan tool communicate with the ECM? —
System OK Go to Step 3
Step
Action Value(s)Yes No

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-63
Engine Cranks but Does Not Run
Description
The Engine Cranks but Does Not Run diagnostic table
is an organized approach to identifying a condition that
causes an engine to not start. The diagnostic table
directs the service technician to the appropriate system
diagnosis. The diagnostic table assumes the following
conditions are met:
• The battery is completely charged and terminals are cleaned and tight.
• The engine cranking speed is normal.
• There is adequate fuel in the fuel tank.
• There is no fuel leak in the fuel line.
• There is no air in the fuel line.
• Filters (air, fuel) are clean.
• Fuse and slow blow fuse are normal. Diagnostic Aids
• If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Test Description
The number below refers to the step number on the
Circuit/ System Testing.
5. If the fuel rail pressure (FRP) regulator low side
circuits between the ECM and the FRP regulator are
shorted to ground, FRP Regulator Feedback will be
approximately 400mA lower as compared with normal.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Engine Cranks but Does Not Run (1of 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
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Crank the engine for the specified amount of time.
4. Monitor the DTC Information with a scan tool.
Does the scan tool display any DTCs that failed this
ignition? 15 seconds
Go to Applicable DTC Go to Step 3
3 1. Turn OFF the ignition.
2. Wait 1 minute for the fuel pressure to bleed down from the fuel rail.
3. Turn ON the ignition, with the engine OFF. DO NOT start the engine.
4. Observe the Fuel Rail Pressure parameter with a scan tool.
Does the scan tool indicate the specified value? 0 MPa (0 psi)
Go to Step 4 Go to Step 6
4 Notice:
If the vehicle has run out of fuel, air may
be trapped in the fuel system.
1. Make sure the fuel tank have adequate fuel and the fuel quality is good (take a sample).
2. Observe the Fuel Rail Pressure parameter on the scan tool while cranking over the engine
for 5 seconds.
Does the scan tool indicate more than the specified
value during crank? 20 MPa (2,900
psi)
Go to Step 9 Go to Step 5
5 Observe the FRP Regulator Feedback parameter
on the scan tool while cranking over the engine for
5 seconds.
Does the scan tool indicate more than the specified
value during crank? 1500 mA
Go to 2 of 2 Step 1 Go to Step 8

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E-64 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
61. Turn OFF the ignition.
2. Disconnect the FRP sensor harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the FRP sensor (pins 1, 2 and 3
of E-48).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 47, 48, 68 and 69
of E-90).
6. Test for high resistance on each circuit.
7. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 7
7 Replace the FRP sensor. Refer to FRP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 11
—
8Repair the short to ground between the ECM (pins
50 and 70 of E-90) and the FRP regulator (pin 2 of
E-50).
Did you compete the repair? —
Go to Step 11
—
91. Check for normal readings at key up for the
following sensor inputs: Use the Scan Tool
Data List or a known good vehicle to
determine nominal values.
• Engine Coolant Temperature Sensor
• Barometric Pressure (BARO) Sensor
• Boost Pressure Sensor
• Intake Throttle Position Sensor
2. Repair the circuit(s) or replace the sensor as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
10 1. Other possible causes for the no-start
condition:
• Engine mechanical timing
• Heavily restricted intake or exhaust plugged solid.
• Poor engine compression.
• Water or gasoline contamination in fuel.
2. Repair as necessary.
Did you find and correct the condition? —
Go to Step 11
—
111. Reconnect all previously disconnected
harness connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Attempt to start the engine.
Does the engine start and continue to run? —
Go to Step 12 Go to Step 2
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

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007