2007 ISUZU KB P190 Harness

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-261
51. Test the circuits between the ECM (pins 55
and 56 of E-90) and the intake throttle valve
(pins 1 and 2 of E-38) for a short circuit each
other.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 8
6 1. Test the circuits (which ever voltage reading
did not read within the specified value at Step
3) between the ECM (pins 55 and 56 of E-90)
and the intake throttle valve (pins 1 and 2 of E-
38) for the following conditions:
• An open circuit
• A short to ground
• A short to the position sensor low reference circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 9
7 1. Test the circuits (which ever voltage reading
did not read within the specified value at Step
3) between the ECM (pins 55 and 56 of E-90)
and the intake throttle valve (pins 1 and 2 of E-
38) 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 12 Go to Step 11
8 1. Inspect for an intermittent and for poor
connections at the harness connector of the
intake throttle valve (pins 1 and 2 of E-38).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 10
9 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 55 and 56 of E-90).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 11
10 Replace the intake throttle valve. Refer to Intake
Throttle Valve Replacement.
Did you complete the replacement? —
Go to Step 10
—
11Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 12
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

6E-262 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
121. 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 13
13 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-264 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
41. Turn OFF the ignition.
2. Disconnect the APP sensor harness connector.
3. Connect a DMM between the 5 volts reference circuit (pin 10 of C-40) and a known good
ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified value? 4.7 volts
Go to Step 5 Go to Step 6
5 Connect a 3-amp fused jumper wire between the 5
volts reference circuit and the signal circuit (pins 5
and 10 of C-40).
Is the APP Sensor 1 parameter more than the
specified value? 4.7 volts
Go to Step 8 Go to Step 7
6 1. Test the 5 volts reference circuit between the
ECM (pin 11 of C-58) and the APP sensor (pin
10 of C-40) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 9
7 1. Test the signal circuit between the ECM (pin
12 of C-58) and the APP sensor (pin 5 of C-
40) for the following conditions:
• An open circuit
• A short to ground
• A short to the low reference circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 9
8 1. Inspect for an intermittent and for poor
connections at the harness connector of the
APP sensor (pins 5 and 10 of C-40).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 10
9 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 11 and 12 of C-58).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 11
10 Replace the APP sensor. Refer to APP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 12
—
11Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 12
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-265
Circuit/ System Testing DTC P2123
121. 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. Fully depress and release the accelerator pedal while observing the APP Sensor 1
parameter with the scan tool.
Does the scan tool indicate less than the specified
value during depressing or releasing the pedal? 0.2 volts
Go to Step 3 Go to Step 13
13 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. Fully depress and release the accelerator pedal while observing the Accelerator Pedal
Position (APP) Sensor 1 parameter with a
scan tool.
Does the scan tool indicate more than the specified
value during depressing or releasing the pedal? 4.8 volts
Go to Step 3 Go to Diagnostic
Aids
3 Monitor the DTC Information with a scan tool.
Is DTC P0643 also set? —
Go to Step 4 Go to Step 5
4 1. Turn OFF the ignition.
2. Disconnect the APP sensor harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the APP Sensor 1 parameter less than the
specified value? 0.1 volts
Go to DTC P0643 Go to Step 7
5 1. Turn OFF the ignition.
2. Disconnect the APP sensor harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the APP Sensor 1 parameter less than the
specified value? 0.1 volts
Go to Step 6 Go to Step 7
6 Connect a test lamp between the low reference
circuit (pin 4 of C-40) and battery voltage.
Does the test lamp illuminate? —
Go to Step 9 Go to Step 8

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ISUZU KB P190 2007

6E-266 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
7Important:
The APP sensor 1 may be damaged if
the sensor signal circuit is shorted to a voltage
source.
1. Test the signal circuit between the ECM (pin 12 of C-58) and the APP sensor (pin 5 of C-
40) for the following conditions:
• A short to battery or ignition voltage
• A short to any 5 volts reference
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
8 1. Test the low reference circuit between the
ECM (pin 27 of C-58) and the APP sensor (pin
4 of C-40) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 10
9 1. Inspect for an intermittent and for a poor
connection at the harness connector of the
APP sensor (pin 4 of C-40).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 11
10 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
ECM (pin 27 of C-58).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
11 Replace the APP sensor. Refer to APP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 13
—
12Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 13
—
131. 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. Fully depress and release the accelerator pedal while observing the APP Sensor 1
parameter with the scan tool.
Does the scan tool indicate more than the specified
value during depressing or releasing the pedal? 4.8 volts
Go to Step 3 Go to Step 14
14 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-267
DTC P2127 or P2128 (Flash Code 122)
Circuit Description
The accelerator pedal position (APP) sensor is
mounted on the accelerator pedal control assembly.
The sensor is made up of three individual sensors
within one housing. The ECM uses the APP sensors to
determine the amount of acceleration or deceleration
that is desired. The APP sensor 2 has the following
circuits.
• 5 volts reference circuit
• Low reference circuit
• APP sensor 2 signal circuit
The APP sensor 2 provides a signal to the ECM on the
signal circuit, which is relative to the position changes
of the accelerator pedal angle. If the ECM detects an
excessively low or high signal voltage, DTC P2127 or
P2128 will set.
Condition for Running the DTC • DTCs P0652 and P0653 are not set.
• The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects that the APP sensor 2 signal voltage is less than 0.15 volts. (DTC P2127)
• The ECM detects that the APP sensor 2 signal voltage is more than 4.85 volts. (DTC P2128) Action Taken When the DTC Sets
• The ECM illuminates the SVS lamp when the diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. (Euro 4 Specification)
• 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.
(Except Euro 4 Specification)
• The ECM limits fuel injection quantity.
• The ECM inhibits cruise control.
Condition for Clearing the DTC • Refer to DTC Type Definitions for Condition for Clearing the SVS Lamp/ DTC - Type C. (Euro 4
Specification)
• Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A. (Except Euro 4
Specification)
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• APP sensor 2 may have an intermittent open somewhere in the pedal range.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P2127
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.
Is DTC P0652 also set? —
Go to DTC P0652 Go to Step 3
3 Fully depress and release the accelerator pedal
while observing the Accelerator Pedal Position
(APP) Sensor 2 parameter with a scan tool.
Does the scan tool indicate less than the specified
value during depressing or releasing the pedal? 0.2 volts
Go to Step 4 Go to Diagnostic
Aids
4 1. Turn OFF the ignition.
2. Disconnect the APP sensor harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the APP Sensor 2 parameter more than the
specified value? 4.7 volts
Go to Step 5 Go to Step 6

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ISUZU KB P190 2007

6E-268 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
5Connect a DMM between the 5 volts reference
circuit (pin 8 of C-40) and a known good ground.
Is the DMM voltage more than the specified value? 4.7 volts
Go to Step 8 Go to Step 7
6 1. Test the signal circuit between the ECM (pin
10 of C-58) and the APP sensor (pin 9 of C-
40) for the following conditions:
• A short to ground
• A short to the low reference circuit
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 11
7 1. Test the 5 volts reference circuit between the
ECM (pin 9 of C-58) and the APP sensor (pin
8 of C-40) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 9
8 1. Inspect for an intermittent and for a poor
connection at the harness connector of the
APP sensor (pin 8 of C-40).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 10
9 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor connection at the harness connector of the
ECM (pin 9 of C-58).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 12 Go to Step 11
10 Replace the APP sensor. Refer to APP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 12
—
11Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 12
—
121. 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. Fully depress and release the accelerator pedal while observing the APP Sensor 2
parameter with the scan tool.
Does the scan tool indicate less than the specified
value during depressing or releasing the pedal? 0.2 volts
Go to Step 3 Go to Step 13
13 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-269
Circuit/ System Testing DTC P2128
StepAction 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.
Is DTC P0653 also set? —
Go to DTC P0653 Go to Step 3
3 Fully depress and release the accelerator pedal
while observing the Accelerator Pedal Position
(APP) Sensor 2 parameter with a scan tool.
Does the scan tool indicate more than the specified
value during depressing or releasing the pedal? 4.8 volts
Go to Step 4 Go to Diagnostic
Aids
4 1. Turn OFF the ignition.
2. Disconnect the APP sensor harness connector.
3. Connect a DMM between the signal circuit (pin 9 of C-40) and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified value? 5.3 volts
Go to Step 10 Go to Step 5
5 1. Connect a test lamp between the signal circuit
of the sensor 2 harness (pin 9 of C-40) and a
known good ground.
2. Connect a DMM between the probe of the test lamp and a known good ground.
Is the DMM voltage more than the specified value? 4.7 volts
Go to Step 9 Go to Step 6
6 Connect a 3-amp fused jumper wire between the
signal circuit and the low reference circuit of the
sensor 2 harness (pins 3 and 9 of C-40).
Is the APP Sensor 2 parameter less than the
specified value? 0.2 volts
Go to Step 11 Go to Step 7
7 1. Test the low reference circuit between the
ECM (pin 25 of C-58) and the APP sensor (pin
3 of C-40) 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 8
8 1. Test the signal circuit between the ECM (pin
10 of C-58) and the APP sensor (pin 9 of C-
40) 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 12
9 1. Test the signal circuit between the ECM (pin
10 of C-58) and the APP sensor (pin 9 of C-
40) for short to any 5 volts reference circuit.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 14

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ISUZU KB P190 2007