2007 ISUZU KB P190 ignition

6E-204 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Circuit/ System Testing DTC P0643
5Replace the APP sensor. Refer to APP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 7
—
6Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 7
—
71. 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 3 Go to Step 8
8 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
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. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids
3 1. Test the 5 volts reference circuit between the
ECM (pin 11 of C-58) and the APP sensor 1
(pin 10 of C-40) 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 5 Go to Step 4
4 Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 5
—

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-205
51. 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 3 Go to Step 6
6 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

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ISUZU KB P190 2007

6E-206 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P0650 (Flash Code 77)
Circuit Description
The malfunction indicator lamp (MIL) is located on the
instrument panel (IP) cluster. The MIL informs the
driver that an emission system fault has occurred and
that the engine control system requires service.
The ECM monitors the MIL control circuit for conditions
that are incorrect for the commanded state of the MIL.
For example, a failure condition exists if the ECM
detects low voltage when the MIL is commanded OFF,
or high voltage when the MIL is commanded ON. If the
ECM detects an improper voltage level on the control
circuit, this DTC will set.
Condition for Running the DTC • The ignition voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC
Either of following condition is met: • The ECM detects a low voltage condition on the MIL control circuit when the lamp is commanded
OFF. • The ECM detects a high voltage condition on the
MIL control circuit when the lamp is commanded
ON.
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.
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.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0650
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. Verify whether the instrument panel (IP)
cluster is operational.
2. Install a scan tool.
3. Perform the Malfunction Indicator Lamp (MIL) Control with a scan tool.
4. Command the lamp ON and OFF.
Does the MIL turn ON and OFF with each
command? —
Go to Diagnostic Aids Go to Step 3
3 1. Turn OFF the ignition.
2. Inspect the Meter (10A) fuse in the cabin fuse block.
Is the Meter (10A) fuse open? —
Go to Step 4 Go to Step 5
4 Replace the Meter (10A) fuse. If the fuse continues
to open, repair the short to ground on one of the
circuits that is fed by the Meter (10A) fuse or
replace the shorted attached component.
Did you complete the repair? —
Go to Step 17
—
51. Turn OFF the ignition.
2. Disconnect the ECM J-2 (C-58) harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the MIL OFF? —
Go to Sep 6 Go to Step 12

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-207
61. Remove the Meter (10A) fuse that supplies
voltage to the MIL.
2. Turn ON the ignition, with the engine OFF.
3. Measure the voltage from the MIL control circuit in the ECM harness connector (pin 57
of C-58) to a known good ground.
Is the voltage less than the specified value? 1 volt
Go to Step 7 Go to Step 13
7 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 ECM harness connector (pin 57 of C-58)
and a known good ground.
Is the MIL illuminated? —
Go to Step 11 Go to Step 8
8 1. Turn OFF the ignition.
2. Remove the IP cluster.
3. Connect a test lamp between the ignition voltage feed circuit of the IP cluster harness
connector (pin 8 of B-24) and a known good
ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? —
Go to Step 9 Go to Step 14
9 1. Test the control circuit between the ECM (pin
57 of C-58) and the IP cluster (pin 38 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 17 Go to Step 10
10 1. Inspect for an intermittent and for poor
connections at the harness connector of the
IP cluster (pin 8 of B-24 and pin 38 of B-23).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 17 Go to Step 15
11 1. Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 57 of C-58).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 17 Go to Step 16
12 Repair the short to ground between the ECM (pin
57 of C-58) and the IP cluster (pin 38 of B-23).
Did you complete the repair? —
Go to Step 17
—
13Repair the short to battery or ignition voltage
between the ECM (pin 57 of C-58) and the IP
cluster (pin 38 of B-23).
Did you complete the repair? —
Go to Step 17
—
14Repair the open circuit or high resistance on the
ignition voltage feed circuit between the Meter
(10A) fuse and the IP cluster (pin 8 of B-24).
Did you complete the repair? —
Go to Step 17
—
15Repair or replace the IP cluster.
Did you complete the repair or replacement? —
Go to Step 17—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

6E-208 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
16Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 17
—
171. Reconnect all previously disconnected fuse or
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Perform the MIL Control with a scan tool.
5. Command the lamp ON and OFF.
Does the MIL turn ON and OFF with each
command? —
Go to Step 18 Go to Step 3
18 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

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-209
DTC P0652 or P0653 (Flash Code 56)
Circuit Description
The ECM provides 5 volts reference voltage through
the reference circuit 2 to the following sensors:
• Accelerator pedal position (APP) sensor 2
• Fuel rail pressure (FRP) sensor
• Barometric pressure (BARO) sensor
• Camshaft position (CMP) sensor
• EGR position sensor
The 5 volts reference circuits are independent of each
other outside the ECM, but are bussed together inside
the ECM. Therefore, a short circuit condition on one 5
volts reference circuit affects the entire 5 volts
reference circuit 2. The ECM monitors the voltage on
the 5 volts reference circuit 2. If the ECM detects the
voltage is excessively low or high, DTC P0652 or
P0653 will set.
Condition for Running the DTC • The battery voltage is more than 6 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects that the 5 volts reference circuit 2 voltage is less than 4.7 volts. (DTC P0652)
• The ECM detects that the 5 volts reference circuit 2 voltage is more than 5.3 volts. (DTC P0653) 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 limits fuel injection quantity.
• The ECM inhibits pilot injection.
• The ECM inhibits EGR control.
• 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.
Notice: • If this DTC is present, the engine cranks but does not start.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0652
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. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition.
2. Disconnect the barometric pressure (BARO) sensor harness connector.
3. Connect a DMM between the 5 volts reference circuit (pin 3 of E-40) and a known good
ground.
4. Turn ON the ignition, with engine OFF.
Is the DMM voltage more than the specified value? 4.7 volts
Go to Step 9 Go to Step 4

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ISUZU KB P190 2007

6E-210 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
41. Leave the DMM connected to the BARO
sensor harness connector.
2. Turn OFF the ignition.
3. Disconnect the EGR valve harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value? 4.7 volts
Go to Step 10 Go to Step 5
5 1. Leave the DMM connected to the BARO
sensor harness connector.
2. Turn OFF the ignition.
3. Disconnect the fuel rail pressure (FRP) sensor harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value? 4.7 volts
Go to Step 11 Go to Step 6
6 1. Leave the DMM connected to the BARO
sensor harness connector.
2. Turn OFF the ignition.
3. Disconnect the camshaft position (CMP) sensor harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value? 4.7 volts
Go to Step 12 Go to Step 7
7 1. Leave the DMM connected to the BARO
sensor harness connector.
2. Turn OFF the ignition.
3. Disconnect the accelerator pedal position (APP) sensor harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value? 4.7 volts
Go to Step 13 Go to Step 8
8 1. Test the 5 volts reference circuit between the
ECM and the following components for a short
to ground or short to the low reference circuit:
• ECM (pin 19 of E-90) and BARO sensor (pin 3 of E-40)
• ECM (pin 31 of E-90) and EGR position sensor (pin 1 of E-71)
• ECM (pin 47 of E-90) and FRP sensor (pin 3 of E-48)
• ECM (pin 46 of E-90) and CMP sensor (pin 3 of E-39)
• ECM (pin 9 of C-58) and APP sensor 2 (pin 8 of C-40)
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 14
9 Replace the BARO sensor. Refer to BARO Sensor
Replacement.
Did you complete the replacement? —
Go to Step 15
—
10Replace the EGR valve. Refer to EGR Valve
Replacement.
Did you complete the replacement? —
Go to Step 15
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-211
Circuit/ System Testing DTC P0653
11Replace the FRP sensor. Refer to FRP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 15
—
12Replace the CMP sensor. Refer to CMP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 15
—
13Replace the APP sensor. Refer to APP Sensor
Replacement.
Did you complete the 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
—
151. 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 3 Go to Step 16
16 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
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. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 3 Go to Diagnostic
Aids

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TO MODEL INDEX
ISUZU KB P190 2007