2007 ISUZU KB P190 Harness

6E-88 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
61. Turn OFF the ignition for 30 seconds.
2. Disconnect the FRP regulator harness connector.
3. Connect a test lamp between the high side circuit (pin 1 of E-50) and a known good
ground.
4. Turn ON the ignition, with the engine OFF. DO NOT start the engine.
Does the test lamp illuminate then go out? —
Go to Step 7 Go to Step 10
7 1. Turn OFF the ignition for 30 seconds.
2. Connect a test lamp between the low side circuit (pin 2 of E-50) and battery voltage.
3. Turn ON the ignition, with the engine OFF. DO NOT start the engine.
Does the test lamp illuminate then go out? —
Go to Step 12 Go to Step 11
8 1. Test the high side circuits between the ECM
(pins 34 and 54 of E-90) and the FRP
regulator (pin 1 of E-50) 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 16 Go to Step 15
9 1. Test the low side circuits between the ECM
(pins 50 and 70 of E-90) and the FRP
regulator (pin 2 of E-50) for a short to ground.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 15
10 1. Test the high side circuits between the ECM
(pins 34 and 54 of E-90) and the FRP
regulator (pin 1 of E-50) for the following
conditions:
• An open circuit
• A short to ground
• A short to the low side circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 13
11 Important:
The ECM may be damaged if the FRP
regulator low side circuit is shorted to a voltage
source.
1. Test the low side circuits between the ECM (pins 50 and 70 of E-90) and the FRP
regulator (pin 2 of E-50) for the following
conditions:
• An open circuit
• A short to battery or ignition voltage
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 13
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-89
121. Inspect for an intermittent and for poor
connections at the harness connector of the
FRP regulator (pins 1 and 2 of E-50).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 14
13 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 34, 50, 54 and 70 of E-90).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 15
14 Replace the FRP regulator. Refer to Fuel Pump
Replacement.
Did you complete the replacement? —
Go to Step 16
—
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. 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 17
17 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-93
91. Remove the fuel hose that connects to the fuel
supply pump suction side and substitute a
clear hose.
Notice: The hose must be cleaned before
connecting to the fuel line. Otherwise, foreign
material internal to the hose may damage the fuel
supply pump.
2. Bleed the fuel system. Repeat as necessary until the engine starts.
3. Let the engine run at idle for at least 1 minute.
4. Observe the clear hose while holding the engine speed higher than 3000 RPM for a
minimum of 1 minute.
Notice: If many air bubbles appear in the fuel,
check the fuel line connections between the fuel
supply pump and the fuel tank for tightness and all
fuel hoses for cuts, cranks and for the uses of
proper clamps.
5. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 10
10 1. Turn OFF the ignition.
2. Disconnect the FRP regulator harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the FRP regulator (pins 1 and 2
of E-50).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 34, 50, 54 and 70
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 16 Go to Step 15
11 1. 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 16 Go to Step 12
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

6E-94 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
12Replace the FRP sensor. Refer to FRP Sensor
Replacement.
Did you complete the replacement? —
Go to Step 16
—
13Important:
Replacement fuel injector must be
programmed.
Replace the appropriate fuel injector that was
leaking fuel found at Step 3 and inspect the engine
mechanical for any damage or poor engine
compression. Refer to Fuel Injector Replacement/
Fuel Injector ID Code Data Programming and
engine mechanical section.
Did you complete the replacement? —
Go to Step 16
—
14Important:
Replacement fuel injector must be
programmed.
Replace the appropriate fuel injector that does not
change engine speed when commanded OFF.
Refer to Fuel Injector Replacement/ Fuel Injector
ID Code Data Programming.
Did you complete the replacement? —
Go to Step 16
—
15Important:
The fuel supply pump must be timed to
the engine and adjustment value must be learned
to the ECM.
Notice: Always replace the fuel filter cartridge
when a fuel supply pump is replaced.
Replace the fuel supply pump and fuel filter
cartridge. Refer to Fuel Supply Pump Replacement
and Fuel Filter Cartridge Replacement.
Did you complete the replacement? —
Go to Step 16
—
161. 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 2 Go to Step 17
17 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-96 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
21. Inspect the following conditions:
• Restricted air cleaner element, restrictedor collapsed air tubing between the air
cleaner and the intake manifold
• Any air induction leak
• Any contamination or objects that block the MAF sensor inlet
• Skewed or slow MAF sensor
• Any water intrusion in the induction system
• Any type of restriction in the exhaust system
• A sticking intake throttle valve
• A sticking EGR valve
• A sticking turbocharger nozzle control actuator or solenoid valve
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 6 Go to Step 3
3 1. Turn OFF the ignition.
2. Disconnect the MAF sensor harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the MAF sensor (pins 1, 2 and 3
of E-47).
4. Disconnect the ECM harness connector.
5. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 40, 42 and 43 of
E-90).
6. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 6 Go to Step 4
4 1. Test each sensor circuit between the ECM
(pins 40 and 43 of E-90) and the MAF sensor
(pins 2 and 3 of E-47) for high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 6 Go to Step 5
5 Replace the MAF sensor. Refer to MAF Sensor
Replacement.
Did you complete the replacement? —
Go to Step 6
—
61. 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 2 Go to Step 7
Step Action Value(s) Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-99
31. Turn OFF the ignition.
2. Disconnect the MAF sensor harness connector.
3. Connect a test lamp between the ignition voltage feed circuit (pin 1 of E-47) and a
known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate? —
Go to Step 4 Go to Step 5
4 1. Turn OFF the ignition for 30 seconds.
2. Connect a 3-amp fused jumper wire between the ignition voltage feed circuit and the signal
circuit (pins 1 and 3 of E-47).
3. Turn ON the ignition, with the engine OFF.
Is the MAF Sensor parameter more than the
specified value? 4.9 volts
Go to Step 7 Go to Step 6
5 Repair the open circuit or high resistance between
the ECM Main Relay (pin 1 of X-12) and the MAF
sensor (pin 1 of E-47) for and open circuit or high
resistance. Check the Engine (10A) fuse first.
Did you complete the repair? —
Go to Step 11
—
61. Test the signal circuit between the ECM (pin
40 of E-90) and the MAF sensor (pin 3 of E-
47) 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 11 Go to Step 8
7 1. Inspect for an intermittent and for poor
connections at the harness connector of the
MAF sensor (pins 1 and 3 of E-47).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 9
8 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 40 of E-90).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
9 Replace the MAF sensor. Refer to MAF Sensor
Replacement.
Did you complete the replacement? —
Go to Step 11
—
10Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 11
—
Step Action Value(s)Yes No

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ISUZU KB P190 2007

6E-100 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Circuit/ System Testing DTC P0103
111. Reconnect all previously disconnected fuse,
relay or 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 2 Go to Step 12
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
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. Observe the Mass Air Flow (MAF) Sensor parameter with a scan tool.
Is the MAF Sensor parameter more than the
specified value? 4.9 volts
Go to Step 3 Go to Diagnostic
Aids
3 1. Turn OFF the ignition for 30 seconds.
2. Disconnect the MAF sensor harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the MAF Sensor parameter less than the
specified value? 0.1 volts
Go to Step 4 Go to Step 5
4 Connect a test lamp between the low reference
circuit (pin 2 of E-47) and battery voltage.
Does the test lamp illuminate? —
Go to Step 7 Go to Step 6
5 1. Test the signal circuit between the ECM (pin
40 of E-90) and the MAF sensor (pin 3 of E-
47) 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 11 Go to Step 10
6 1. Test the low reference circuit between the
ECM (pin 43 of E-90) and the MAF sensor (pin
2 of E-47) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 8

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-101
71. Inspect for an intermittent and for a poor
connection at the harness connector of the
MAF sensor (pin 2 of E-47).
2. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 9
8 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 43 of E-90).
4. Repair the connection(s) as necessary.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
9 Replace the MAF sensor. Refer to MAF Sensor
Replacement.
Did you complete the replacement? —
Go to Step 11
—
10Important:
Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement? —
Go to Step 11
—
111. 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 2 Go to Step 12
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