2007 ISUZU KB P190 reset

Engine Management – V6 – Diagnostics Page 6C1-2–165

Step Action Yes
No
10 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does DTC P0850 fail this ignition cycle? Go to Step 2 Go to Step 11
11 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.43 DTC P1648
DTC Descriptor
This diagnostic procedure supports DTC P1648 – W rong Security Code Entered.
Circuit Description
Tech 2 is used to program the engine control module (ECM). Before any programming, a security code must be entered
into Tech 2. The ECM will check if the code entered is correct before continuing. If the security code is incorrect, DTC
P1648 sets.
Conditions for Running the DTC
Conditions for running the DTC are:
• The ignition is switched on.
• The ignition voltage is 10.0 – 16.0 V.
Conditions for Setting the DTC
An incorrect security code is entered into Tech 2 when attempting to program the ECM.
Action Taken When the DTC Sets
W hen the DTC sets, the malfunction indicator lamp (MIL) is not displayed.
Conditions for Clearing the DTC
The immobiliser security code is a Type ‘C’ DTC. Refer to 1.4 Diagnostic Trouble Codes in this Section, for action
taken when a Type ‘C’ DTC sets and conditions for clearing Type ‘C’ DTCs.
Additional Information
• Refer to 6C1-1 Engine Management –V6 – General Information for details of the ECM operation.
• Refer to 6C1-3 Engine Management –V6 – Service Operations for details on resetting the ECM.
• Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical -
Body and Chassis for information on electrical fault diagnosis.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.

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Engine Management – V6 – Diagnostics Page 6C1-2–166

Test Description
The following numbers refer to the step numbers in the diagnostic table:
4 This step tests the ECM ground circuits and supply voltage.
DTC P1648 Diagnostic Table
Step Action Yes No
1 Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 1 Switch off the ignition for 30 seconds.
2 Using Tech 2, select the DTC display function.
NOTE
Do not attempt to perform any Tech 2 function that
requires the ECM security code to be entered.
Does DTC P1648 fail this ignition cycle? Go to Step 4 Go to Step 3
3 Using Tech 2, attempt a programming function that requires the ECM
security code to be entered. Refer to 6C1-3 Engine Management –V6
– Service Operations for details on resetting the ECM.
Has the programming function been successfully performed? System OK Go to Step 4
4 1 Test all ECM ground circuits for a high resistance or an open
circuit fault condition. Refer to 8A Electrical - Body and Chassis
for information on electrical fault diagnosis.
2 Test the ECM ignition supply voltage circuit for a high resistance, open circuit or short to ground fault condition. Refer
to 8A Electrical - Body and Chassis for information on electrical
fault diagnosis.
Has any fault been found and rectified? Go to Step 6 Go to Step 5
5 Replace the ECM. Refer to 6C1-3 Engine Management –V6 – Service
Operations for details on replacing the ECM.
Has the repair been completed? Go to Step 6 —
6 1 Using Tech 2, clear the DTCs.
2 Switch off the ignition for 30 seconds.
Does DTC P1648 fail this ignition cycle? Go to Step 2 Go to Step 7
7 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, clear all DTCs and check the system for correct operation.
7.44 DTC P1668, P2500 or P2501
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P1668 – Generator L Terminal Circuit Malfunction
• DTC P2500 – Generator L Terminal Low Voltage
• DTC P2501 – Generator L Terminal High Voltage

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–173

10 1 Ignition OFF.
2 Disconnect the front and rear HO2S.
3 Inspect the front and rear HO2S for the following conditions:
− Damaged wiring between the HO2S and
the ECM – An intermittent circuit condition
causes this DTC to set.
− Terminal corrosion or water intrusion in the
HO2S harness connectors.
− The correct terminal tension.
− The HO2S is securely installed.
− Any exhaust leaks – Refer to 6F Exhaust
System – V6.
4 Repair as necessary. Refer to 8A Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 11
11 1 Disconnect the ECM.
2 Test the appropriate front HO2S circuits for being shorted together between the HO2S connector
and the ECM. Refer to 8A Electrical - Body and
Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 13
12 1 Test for shorted terminals and for poor
connections at the HO2S. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 17
13 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 16
14 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 18
15 1 Repair the circuit as necessary. Refer to 8A
Electrical - Body and Chassis.
Did you complete the repair? —
Go to Step 19 —
16 1 Replace the appropriate HO2S. Refer to the
Oxygen Sensor 1 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
17 1 Replace the appropriate HO2S. Refer to the
Oxygen Sensor 2 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
18 1 Replace the ECM. Refer to Engine Control
Module (ECM) Remove, Reinstall and ECM
Reset in 6C1- Engine Management – V6 Service
Operations.
Did you complete the replacement? —
Go to Step 19 —

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–177

10 1 Ignition OFF.
2 Disconnect the front and rear HO2S.
3 Inspect the front and rear HO2S for the following conditions:
− Damaged wiring between the HO2S and
the ECM – An intermittent circuit condition
causes this DTC to set.
− Terminal corrosion or water intrusion in the
HO2S harness connectors.
− The correct terminal tension.
− The HO2S is securely installed.
− Any exhaust leaks – Refer to 6F Exhaust
System – V6.
4 Repair as necessary. Refer to 8A Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 11
11 1 Disconnect the ECM.
2 Test the appropriate front HO2S circuits for being shorted together between the HO2S connector
and the ECM. Refer to 8A Electrical - Body and
Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 13
12 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 17
13 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 16
14 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 18
15 1 Repair the circuit as necessary. Refer to 8A
Electrical - Body and Chassis.
Did you complete the repair? —
Go to Step 19 —
16 1 Replace the appropriate HO2S. Refer to the
Oxygen Sensor 1 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
17 1 Replace the appropriate HO2S. Refer to the
Oxygen Sensor 2 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
18 1 Replace the ECM. Refer to Engine Control
Module (ECM) Remove, Reinstall and ECM
Reset in 6C1- Engine Management – V6 Service
Operations.
Did you complete the replacement? —
Go to Step 19 —

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–190

5 1 Start the engine.
NOTE
Additional DTCs will set when the MAF
sensor is disconnected.
2 Disconnect the mass air flow (MAF) sensor harness connector while the engine is operating.
3 Observe the Short Term FT parameter for Bank 1 and bank 2 with Tech 2.
4 Reconnect the MAF sensor after completing this step.
Does the Short Term FT parameter for both banks of
the engine change more than the specified value with
the MAF sensor disconnected? 20%
Go to 7.6
DTC
P0101, P0102 or P0103 in this Section Go to Step 6
6 1 Inspect for the following conditions:
− A collapsed air intake duct
− A restricted air filter element
− The MAF sensor for foreign objects
− Excessive fuel in the crankcase – Change
the oil as necessary.
− Contaminated fuel. Refer to 6.5 Alcohol /
Contaminants in Fuel Diagnosis in this
Section.
− The ECM grounds for being clean, tight,
and in the correct locations
− An engine mechanical condition – refer to
6A1 – Engine Mechanical V6.
Did you find and correct the condition? —
Go to Step 8 Go to 6C Fuel
System – V6
7 1 Inspect for the following conditions:
− Rich injectors – refer to 6.2 Fuel
Injector Coil Test in this Section
− Restricted exhaust system – refer to 6F
Exhaust System – V6
− An engine mechanical condition – refer to
6A1 – Engine Mechanical V6.
Did you find and correct the condition? —
Go to Step 8 Go to Additional
Information in this Section.
8 1 Switch off the ignition for 30 seconds.
2 Using Tech 2, clear the DTCs and reset the fuel trim system.
3 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 DTC P2178 and / or P2180 fail this ignition cycle? —
Go to Step 2 Go to Step 9
9 1 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? —
Go to the
appropriate DTC Table in this Section System OK

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–197

8 1 Turn OFF the ignition for 30 seconds.
2 Using Tech 2, clear the DTCs and reset the fuel trim system.
3 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 DTC P2188 and / or P2190 fail this ignition cycle? —
Go to Step 2 Go to Step 9
9 1 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTCs? —
Go to the
appropriate DTC Table in this Section System OK
7.55 DTC P2195 or P2197
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P2195 – B1S1 O2 Sensor – System Too Lean (Bank 1 Sensor 1)
• DTC P2197 – B2S1 O2 Sensor – System Too Lean (Bank 2 Sensor 1)
Circuit Description
The wide band heated oxygen sensor 1 (HO2S1) measures the amount of oxygen in the exhaust system and provides
more information than the switching style HO2S2. The wide band sensor consists of an oxygen sensing cell, an oxygen
pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the
pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to
the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the
oxygen pumping cell, maintaining a constant voltage in the oxygen sensing cell.
The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or
decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current
required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust.
The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of
14.7:1.
Under normal operating conditions, the lambda value will remain around 1. W hen the fuel system is lean, the oxygen
level will be high and the lambda signal will be high or more than 1. W hen the fuel system is rich, the oxygen level will
be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air / fuel
ratio.
Conditions for Running the DTC
• Before the ECM can report DTC P2195 or P2197 failed, DTCs P0137, P0138, P0140, P0141, P0157, P0158,
P0160, P0161, P2270, P2271, P2272, and P2273 must run and pass.
• The front and rear heated oxygen sensors are at operating temperature.
• The rear HO2S voltage signal is more than 850 mV.
• The front HO2S is more than 1.08 lambda.
• The Loop Status for both the front and rear sensors is Closed Loop.
• DTCs P2195 and P2197 run continuously once the above conditions are met.
Conditions for Setting the DTC
Condition 1
• The ECM detects that the front HO2S is operating too lean while the rear HO2S is operating too rich and the ECM
detects that the fuel trim is at maximum control,
OR

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–201

18 1 Replace the ECM. Refer to Engine Control
Module (ECM) Remove, Reinstall and ECM
Reset in 6C1- Engine Management – V6 Service
Operations.
Did you complete the replacement? —
Go to Step 19 —
19 1 Clear the DTCs, using Tech 2.
2 Turn OFF the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does DTC P2195 or P2197 fail this ignition cycle? —
Go to Step 2 Go to Step 20
20 1 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTC? —
Go to the
appropriate DTC Table in this Section System OK
When all diagnosis and repairs are completed, clear all DTCs and verify correct operation
7.56 P2196 or P2198
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P2196 – B1S1 O2 Sensor – System Too Rich (Bank 1 Sensor 1)
• DTC P2198 – B2S1 O2 Sensor – System Too Rich (Bank 2 Sensor 1)
Circuit Description
The wide band heated oxygen sensor 1 (HO2S1) measures the amount of oxygen in the exhaust system and provides
more information than the switching style HO2S2. The wide band sensor consists of an oxygen sensing cell, an oxygen
pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the
pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to
the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the
oxygen pumping cell, maintaining a constant voltage in the oxygen sensing cell.
The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or
decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current
required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust.
The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of
14.7:1.
Under normal operating conditions, the lambda value will remain around 1. W hen the fuel system is lean, the oxygen
level will be high and the lambda signal will be high or more than 1. W hen the fuel system is rich, the oxygen level will
be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air / fuel
ratio.
Conditions for Running the DTC
• Before the ECM can report DTC P2196 or P2198 failed, DTCs P0137, P0138, P0140, P0141, P0157, P0158,
P0160, P0161, P2270, P2271, P2272, and P2273 must run and pass.
• The front and rear heated oxygen sensors are at operating temperature.
• The rear HO2S voltage signal is more than 150 mV.
• The front HO2S is more than 0.92 lambda.
• The Loop Status for both the front and rear sensors is Closed Loop.
• DTCs P2196 and P2198 run continuously once the above conditions are met.

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Engine Management – V6 – Diagnostics Page 6C1-2–205

17 1 Replace the HO2S 2. Refer to the Oxygen
Sensor 2 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
18 1 Replace the ECM. Refer to Engine Control
Module (ECM) Remove, Reinstall and ECM
Reset in 6C1- Engine Management – V6 Service
Operations.
Did you complete the replacement? —
Go to Step 19 —
19 1 Clear the DTCs, using Tech 2.
2 Turn OFF the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the conditions for running the DTC.
Does DTC P2196 or P2198 fail this ignition cycle? —
Go to Step 2 Go to Step 20
20 1 Using Tech 2, select the DTC display function.
Does Tech 2 display any DTC? —
Go to the
appropriate DTC Table in this Section System OK
When all diagnosis and repairs are completed, clear all DTCs and verify correct operation

7.57 DTC P2227, P2228 or P2229
DTC Descriptor
This diagnostic procedure supports the following DTCs:
• DTC P2227 – Barometric Pressure Sensor Circuit Range / Performance
• DTC P2228 – Barometric Pressure Sensor Voltage Low
• DTC P2229 – Barometric Pressure Sensor Voltage High
Circuit Description
The ECM applies a positive 5 V reference voltage to the barometric pressure (BARO) sensor through the 5 V reference
circuit and the ground through the low reference circuit.
The BARO sensor provides signal voltage to the ECM that is proportional to the atmospheric pressure changes through
the signal circuit. The ECM uses the BARO signal voltage to maintain the correct fuel delivery at different altitudes.
The ECM monitors and compares the BARO sensor signal voltage against a specified range. A BARO pressure sensor
circuit DTC sets if the ECM detects the BARO sensor signal voltage is outside the specified range.
Conditions for Running the DTC
DTC P2227
Runs continuously once the following conditions are met for 3 seconds:
• DTCs P0121, P0122, P0123, P0221, P0222 or P0223 are not set.
• The engine is running.
DTC P2228 and P2229
Runs continuously once the following conditions are met for 3 seconds:
• DTCs P0101, P0102 or P0103 are not set.

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