2007 ISUZU KB P190 DTC CHECK

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-227
31. 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 (FRP) Sensor parameter with the scan tool.
Does the scan tool indicate within the specified
value? 0.9 to 1.0 volt
Go to Step 4 Go to Step 10
4 1. Turn OFF the ignition.
2. Place the transmission in Neutral and set the parking brake.
3. Start the engine.
4. Accelerate the engine between idle and W.O.T. (accelerator pedal full travel) many
times.
5. Let idle for at least 3 minutes while observing the DTC Information with a scan tool.
Is DTC P1094 set? —
Go to Step 14 Go to Step 5
5 1. Start the engine.
2. Perform the Cylinder Balance Test with a scan tool.
3. Command each injector OFF and verify an engine speed change for each injector.
Is there an injector that does not change engine
speed when commanded OFF? —
Go to Step 12 Go to Step 6
6 1. Check the fuel system line connections
between the fuel tank and the fuel supply
pump for tightness and all fuel hoses for cuts,
cracks and for the use of proper clamps.
Notice: Air in the fuel system will cause fuel rail
pressure fluctuations especially at high engine
speed and load, which may set this DTC.
2. Start the engine and check for high side fuel system leaks at the fuel supply pump and fuel
rail.
Notice: Fuel may leak under the cylinder head
cover from the inlet high pressure line. In such
case, the engine oil level will rise. Inspect for fuel
leakage into the engine oil.
3. Repair any fuel system leaks as necessary.
Did you find and correct the condition? —
Go to Step 15 Go to Step 7
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

6E-232 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Notice:• This DTC most likely indicates a loss of fuel pressure by a fuel leak from the high pressure
side. Inspect the high pressure side fuel leakage
between the fuel supply pump and fuel injector
first. • If the fuel tank is empty or near empty, air might be
allowed to go into the fuel system. With air in the
fuel system, smooth flow of fuel into the supply
pump is interrupted and this DTC may set. Perform
bleeding of fuel system after refilling.
Schematic Reference: Fuel System Routing Diagram
and Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P1094
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. Inspect the high pressure side between the
fuel supply pump and the fuel injectors for fuel
leakage. The following components may
contain an external leak.
• Fuel supply pump
• Fuel rail
• Pressure limiter valve
• Fuel rail pressure (FRP) sensor
• Fuel pipe between the fuel supply pump and fuel rail
• Fuel pipe between the fuel rail and fuel injectors
• Each fuel pipe sleeve nuts
Notice: Fuel may leak under the cylinder head
cover from the inlet high pressure line. In such
case, the engine oil level will rise. Inspect for fuel
leakage into the engine oil.
Notice: Remove and inspect the inlet high
pressure joint to the fuel injectors for fuel leaking
from the sleeve nut(s). Replace the fuel injector
and injection pipe when foreign material was in
contact.
2. Repair any fuel system leaks as necessary.
Did you find and correct the condition? —
Go to Step 19 Go to Step 3
3 1. Remove each glow plug from the cylinder
head.
2. Inspect for fuel leakage into the combustion chamber.
Is there a cylinder that fuel leakage into the
combustion chamber? —
Go to Step 15 Go to Step 4
4 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 P0087, P0091, P0092, P0192, P0193,
P0201 - P0204, P1064, P1065, P124B or P2146 -
P2151 set? —
Go to Applicable DTC Go to Step 5

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-233
51. 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 (FRP) Sensor parameter with the scan tool.
Does the scan tool indicate within the specified
value? 0.9 to 1.0 volt
Go to Step 6 Go to Step 13
6 1. Turn OFF the ignition.
2. Place the transmission in Neutral and set the parking brake.
3. Start the engine and let idle for at least 3 minutes while observing the DTC Information
with a scan tool.
Does the DTC fail this ignition? —
Go to Step 8 Go to Step 7
7 1. Accelerate the engine between idle and
W.O.T. (accelerator pedal full travel) many
times.
2. Let idle for at least 3 minutes while observing the DTC Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 18 Go to Step 8
8 1. Start the engine.
2. Perform the Cylinder Balance Test with a scan tool.
3. Command each injector OFF and verify an engine speed change for each injector.
Is there an injector that does not change engine
speed when commanded OFF? —
Go to Step 16 Go to Step 9
9 1. Check the fuel system line connections
between the fuel tank and the fuel supply
pump for tightness and all fuel hoses for cuts,
cracks and for the use of proper clamps.
Notice: Air in the fuel system will cause fuel rail
pressure fluctuations especially at high engine
speed and load, which may set this DTC.
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 19 Go to Step 10
Step
Action Value(s)Yes No

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-237
DTC P1196, P1197 or P1198 (Flash Code 461)
Circuit Description
The ECM controls the intake throttle valve opening
based on the engine running condition and by
controlling the intake throttle solenoid. The intake
throttle valve position is detected by the position
sensor, and relayed to the ECM. If the ECM detects an
excessively high temperature condition in its internal
intake throttle solenoid drive circuit for certain length of
time, DTC P1196, P1197 or P1198 will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC • The ECM detects an excessively high temperature in its internal intake throttle solenoid drive circuit
for longer than 30 seconds. (DTC P1196)
• The ECM detects an excessively high temperature in its internal intake throttle solenoid drive circuit
for longer than 60 seconds in accumulation time
during same ignition cycle. (DTC P1197) • The ECM detects an excessively high temperature
in its internal intake throttle solenoid drive circuit
for longer than 120 seconds in accumulation time
exceeding ignition cycle. (DTC P1198)
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 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.
• A sticking or intermittently sticking intake throttle valve may set this DTC.
Circuit/ System Testing DTC P1196, P1197 or P1198
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 P0638 also set? —
Go to DTC P0638 Go to Step 3
3 1. Perform the Intake Throttle Solenoid Control
with a scan tool several times.
2. Command the Desired Intake Throttle Position Increase and Decrease while observing the
Intake Throttle Position.
Does the Intake Throttle Position parameter follow
within the specified value quick enough (compare
with a similar unit if available)? ±
5%
Go to Diagnostic Aids Go to Step 4

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-239
DTC P124B (Flash Code 157)
Circuit Description
The ECM calculates the optimum fuel injection ON time
using data sent from various engine sensors. The
common 1 and common 2 fuel injector charge voltage
circuit is a high-voltage supply which drives fuel
injectors for each cylinder in conjunction with the ECM
grounding the fuel injector solenoid control circuit. If the
fuel injector charge voltage circuit or solenoid control
circuit is shorted across the bank, this DTC will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
• The engine speed is lower than 2000RPM.
Condition for Setting the DTC • The ECM detects that the fuel injector charge voltage circuit or solenoid control circuit is shorted
across the bank.
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)
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.
Schematic Reference : Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P124B
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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ISUZU KB P190 2007

6E-242 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P1261 (Flash Code 34)
Circuit Description
The charge up circuit in the ECM steps up the voltage
for fuel injectors and is divided into two banks, common
1 and common 2. The common 1 covers fuel injectors
in cylinders #1 and #4, and the common 2 covers fuel
injectors in cylinders #2 and #3.
If the common 1 fuel injector charge up circuit in the
ECM is an insufficient charge or an overcharge, this
DTC will set. (Charge Up Voltage DTC)
If the supply voltage to the common 1 and common 2
fuel injector charge up circuits is an excessively low or
high voltage, this DTC will also set. (Supply Voltage
Low or High DTC)
Condition for Running the DTC
Charge Up Voltage DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
• The engine is not running.
Supply Voltage Low or High DTC
• The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC
Charge Up Voltage DTC • The ECM detects that the common 1 fuel injector charge up circuit is an insufficient charge or an
overcharge.
Supply Voltage Low or High DTC
• The ECM detects that the supply voltage to the common 1 and common 2 fuel injector charge up
circuits is an excessively low or high voltage.
Action Taken When the DTC Sets
Charge Up Voltage DTC & Supply Voltage Low DTC • 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 cruise control.
Supply Voltage High DTC
• 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
Charge Up Voltage DTC & Supply Voltage Low DTC • Refer to DTC Type Definitions for Condition for Clearing the MIL/ DTC - Type A
Supply Voltage High 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.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P1261
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 Step 8

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ISUZU KB P190 2007

6E-244 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P1262 (Flash Code 34)
Circuit Description
The charge up circuit in the ECM steps up the voltage
for fuel injectors and is divided into two banks, common
1 and common 2. The common 1 covers fuel injectors
in cylinders #1 and #4, and the common 2 covers fuel
injectors in cylinders #2 and #3. If the common 2 fuel
injector charge up circuit in the ECM is an insufficient
charge or an overcharge, this DTC will set.
Condition for Running the DTC • The battery voltage is more than 9 volts.
• The ignition switch is ON.
• The engine is not running.
Condition for Setting the DTC • The ECM detects that the common 2 fuel injector charge up circuit is an insufficient charge or an
overcharge. 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 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.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P1262
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 Step 8
3 1. Inspect for an intermittent, for poor tightening
and corrosion at the engine ground terminal
(E-10).
2. Repair the tightening or clean the corrosion as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 4
4 1. Test ground circuit between the ECM (pin 73
of E-90) and the engine ground terminal (E-
10) for an intermittently open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 5
5 1. Test the battery voltage feed circuit between
the ECM (pin 73 of E-90) and the ECM main
relay (pin 1 of X-12) for an intermittently open
circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 8 Go to Step 6

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ISUZU KB P190 2007

6E-246 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DTC P1404 (Flash Code 45)
Circuit Description
The ECM controls the EGR valve opening based on the
engine running condition and by controlling the EGR
solenoid. The EGR valve position is detected by the
position sensor, and relayed to the ECM.
If the ECM detects that the actual EGR position is
higher than certain amount, this DTC will set. (Closed
Position Error DTC)
If the ECM detects a variance between the learned
closed position and actual closed position, this DTC will
also set. (Learned Position Error DTC)
Condition for Running the DTC
Closed Position Error DTC • DTCs P0112, P0113, P0116, P0117, P0118, P0404 P0405, P0406, P0652, P0653, P2227,
P2228 and P2229 are not set.
• The battery voltage is between 10 to 16 volts.
• The ignition switch is ON.
• The engine coolant temperature is between 20 to 11 0 °C (68 to 230 °F).
• The intake air temperature is between 0 to 110 °C
(32 to 230 °F).
• The barometric pressure is between 60 to 120 kPa (8.7 to 17.4 psi)
Learned Position Error DTC
• DTCs P0404, P0405 and P0406 are not set.
Condition for Setting the DTC
Closed Position Error DTC • The ECM detects that the actual EGR position is
more than 20% for 5 seconds when the EGR
control is commanded OFF.
Learned Position Error DTC
• The ECM detects that the EGR learned minimum position is more than 10% or less than -10% when
the ignition switch is OFF.
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. (Closed Position Error DTC)
• 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.
• A sticking or intermittently sticking EGR valve may set this DTC.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P1404
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 P0403, P0405 or P0406 also set? —
Go to Applicable DTC Go to Step 3
3 1. Remove the EGR valve assembly from the
engine.
2. Inspect the EGR valve for the following conditions:
• Restricted EGR valve by foreign materials
• Excessive deposits at valve
• Bent valve shaft
3. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 6 Go to Step 4

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ISUZU KB P190 2007