2007 ISUZU KB P190 Circuit

Engine Management – V6 – Diagnostics Page 6C1-2–79

• The TP sensor 2 signal voltage is 0.15 – 4.8 V.
DTC P0222 runs continuously once the following conditions are met:
• The battery voltage is greater than 7 V.
• The ignition is switched on.
Conditions for Setting the DTC
DTC P0121
The following conditions exist:
• The TP sensor 1 signal voltage and the TP sensor 2 signal voltage have a difference of greater than 9 percent.
• The TP sensor signal voltage has a difference of greater than 9 percent from the calculated TP sensor signal
voltage.
DTC P0122
The ECM detects the TP sensor 1 signal voltage is less than 0.18 volt.
DTC P0123
The ECM detects the TP sensor 1 signal voltage is greater than 4.6 V.
DTC P0221
The following conditions exist:
• The TP sensor 2 signal voltage and the TP sensor 1 signal voltage have a difference of greater than 9 percent.
• The TP sensor 2 signal voltage has a difference of greater than 9 percent from the calculated TP sensor signal
voltage.
DTC P0222
The ECM detects the TP sensor 2 signal voltage is less than 0.16 volt.
DTC P0223
The ECM detects the TP sensor 2 signal voltage is greater than 4.8 V.
Conditions for Clearing the DTC
DTCs P0121, P0122, P0123, P0221, P0222 are P0223 are Type B DTCs. Refer to 1.4 Diagnostic Trouble Codes in
this Section, for action taken when a Type B DTC sets and conditions for clearing Type B DTCs.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the TP sensor operation.
• The ECM defaults to a reduced power mode if there is a fault condition in the TP sensor circuits for the entire
ignition cycle, even if the fault condition is corrected.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• The TP sensors share a common 5 V reference circuit, test for a fault condition in the 5 V reference circuit if both
DTCs P0122 and P0222 are set.
• 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.
• 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 6C1-2–80

Test Description
The following number refers to the step number in the diagnostic table:
6 Measures the integrity of the TP sensor low reference circuit. Removal of the ECM Fuse 29 enables the ECM to power down completely prior to the test procedure.
DTC P0121, P0122, P0123, P0221, P0222 or P0223 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 Start the engine.
3 Quickly depress the accelerator pedal to wide-open throttle then release pedal. Repeat this procedure several times or operate
the vehicle within the conditions for running the DTC.
4 Using Tech 2, select the DTC display function.
Does DTC P0121, P0122, P0123, P0221, P0222 or P0223 fail this
ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Disconnect the throttle actuator wiring connector.
2 Switch on the ignition with the engine not running.
3 Using a digital multimeter, measure the voltage between the TP sensor 5 V reference circuit and the ECM housing.
Does the multimeter display 4.8 – 5.2 V? Go to Step 4 Go to Step 7
4 1 Connect a 3 A fused jumper wire between the TP sensor 5 V
reference circuit and the TP sensor 1 signal circuit.
2 Switch on the ignition with the engine not running.
3 Using Tech 2, observe the TP sensor 1 voltage parameter.
Does Tech 2 display 4.8 – 5.2 V?
Go to Step 5 Go to Step 8
5 1 Connect a 3 A fused jumper wire between the TP sensor 5 V
reference circuit and the TP sensor 2 signal circuit.
2 Using Tech 2, observe the TP sensor 2 voltage parameter.
Does Tech 2 display 4.8 – 5.2 V?
Go to Step 6 Go to Step 9
6 1 Switch off the ignition.
2 Remove ECM Fuse 29 from the engine compartment fuse and relay panel assembly.
3 Using a digital multimeter, measure the resistance between the TP sensor low reference circuit and the ECM housing.
NOTE
Install the ECM Fuse 29 to the engine compartment fuse
and relay panel assembly after completing the test.
Does the multimeter display 5 Ω? Go to Step 11 Go to Step 10

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Engine Management – V6 – Diagnostics Page 6C1-2–81

Step Action Yes No
7
NOTE
TP sensor 1 share the 5 V reference circuit with TP sensor
2. A fault condition in the TP sensor 5 V reference circuit
may trigger DTCs on both sensors.
Test the TP sensor 5 V reference circuit for a high resistance, open
circuit, short to ground or short to voltage fault condition. Refer to 8A
Electrical - Body and Chassis for information on electrical fault
diagnosis.
W as any fault found and rectified? Go to Step 13 Go to Step 12
8 Test the TP sensor 1 signal circuit for a high resistance, open circuit,
short to ground or short to voltage fault condition. Refer to 8A
Electrical - Body and Chassis for information on electrical fault
diagnosis.
W as any fault found and rectified? Go to Step 13 Go to Step 12
9 Test the TP sensor 2 signal circuit for a high resistance, open circuit,
short to ground or short to voltage fault condition. Refer to 8A
Electrical - Body and Chassis for information on electrical fault
diagnosis.
W as any fault found and rectified? Go to Step 13 Go to Step 12
10 Test the TP sensor low reference circuit for a high resistance or an
open circuit fault condition. Refer to 8A Electrical - Body and Chassis
for information on electrical fault diagnosis.
W as any fault found and rectified? Go to Step 13 Go to Step 12
11 Replace the throttle body assembly. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
W as the repair completed? Go to Step 13 —
12 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 13 —
13 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 any of the TP Sensor Circuit DTCs fail this ignition cycle? Go to Step 2 Go to Step 14
14 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.
7.10 DTC P0130, P0131, P0132, P0135, P0137,
P0138, P0140, P0141, P0150 P0151,
P0152, P0155, P0157, P0158, P0160,
P0161, P2243, P2247, P2270, P2271,
P2272, P2273, P2297 or P2298
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0130 – O2 Sensor Circuit Malfunction (Bank 1, Sensor 1)

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–82

• DTC P0131 – O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
• DTC P0132 – O2 Sensor Circuit High Voltage (Bank 1, Sensor 1)
• DTC P0133 –
• DTC P0135 – O2 Sensor Heater Circuit Range / Performance (Bank 1, Sensor 1)
• DTC P0137 – O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
• DTC P0138 – O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)
• DTC P0140 – O2 Sensor Circuit No Activity Detected (Bank 1, Sensor 2)
• DTC P0141 – O2 Sensor Heater Circuit Range / Performance (Bank 1, Sensor 2)
• DTC P0150 – O2 Sensor Circuit Malfunction (Bank 2, Sensor 1)
• DTC P0151 – O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1)
• DTC P0152 – O2 Sensor Circuit High Voltage (Bank 2, Sensor 1)
• DTC P0155 –O2 Sensor Heater Circuit Range / Performance (Bank 2, Sensor 1)
• DTC P0157 – O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)
• DTC P0158 – O2 Sensor Circuit High Voltage (Bank 2, Sensor 2)
• DTC P0160 – O2 Sensor Circuit No Activity Detected (Bank 2, Sensor 2)
• DTC P0161 – O2 Sensor Heater Circuit Range / Performance (Bank 2, Sensor 2)
• DTC P2243 – O2 Sensor Voltage Signal Circuit Malfunction (Bank 1, Sensor 1)
• DTC P2247 – O2 Sensor Voltage Signal Circuit Malfunction (Bank 2, Sensor 1)
• DTC P2270 – O2 Sensor Lean / Rich Switch Signal Malfunction (Bank 1, Sensor 2)
• DTC P2271 – O2 Sensor Rich / Lean Switch Signal Malfunction (Bank 1, Sensor 2)
• DTC P2272 – O2 Sensor Lean / Rich Switch Signal Malfunction (Bank 2, Sensor 2)
• DTC P2273 – O2 Sensor Rich / Lean Switch Signal Malfunction (Bank 2, Sensor 2)
• DTC P2297 – O2 Sensor Range / Performance During Deceleration Fuel Cutoff (Bank 1, Sensor 1)
• DTC P2298 – O2 Sensor Range / Performance During Deceleration Fuel Cutoff (Bank 2, Sensor 1)
Circuit Description
The engine control relay applies positive voltage to the heater ignition voltage circuits of the HO2S. The ECM applies a
pulse width modulated (PW M) ground to the heater control circuit of the HO2S through a device within the ECM called a
driver, to control the HO2S rate of heating.
HO2 Sensor 2
The ECM applies a voltage of approximately 450 mV between the reference signal circuit and low reference circuit of the
HO2S while the sensor temperature is less than the operating range.
Once the HO2S reaches operating temperature, the sensor varies this reference signal voltage, which constantly
fluctuates between the high voltage output and the low voltage output.
• The low voltage output is 0 – 450 mV, which occurs if the air fuel mixture is lean.
• The high voltage output is 450 – 1,000 mV, which occurs if the air fuel mixture is rich.
The ECM monitors, stores and evaluates the HO2S voltage fluctuation information to determine the level of oxygen
concentration in the exhaust.
HO2 Sensor 1
The ECM maintains the voltage between the reference signal circuit and low reference circuit of the HO2S 1 to about
450 mV by increasing or decreasing the oxygen content in the HO2S diffusion gap. To achieve this, the ECM controls
the current applied to the oxygen pumping cell in the HO2S

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Engine Management – V6 – Diagnostics Page 6C1-2–83

The pumping current required to maintain the HO2S 1 signal circuit voltage to about 450 mV is proportional to the level
of oxygen concentration in the exhaust gas.
• If the air/fuel mixture in the exhaust is balanced (lambda = 1), the oxygen pumping cell current is zero.
• If the exhaust gas in the HO2S 1 diffusion gap is lean, the ECM applies a positive current to the oxygen pumping
cell to discharge oxygen from the diffusion gap.
• If the exhaust gas in the HO2S 1 diffusion gap is rich, the ECM applies a negative current to the oxygen pumping
cell to draw oxygen into the diffusion gap.
The ECM monitors and evaluates the oxygen pumping current to determine the level of oxygen concentration in the
exhaust.
An HO2S reference circuit DTC sets if the ECM detects the HO2S signal voltage is outside the predetermined range for
a specified period.
Conditions for Running the DTC
DTC P0130, P0131, P0132, P0137, P0138, P0140, P0150, P0151 or P0152
Run continuously once the following conditions are met:
• The ignition voltage is 10.0 – 16.0 V.
• The engine is running.
DTC P0135 and P0155
Condition 1
Run continuously once the following conditions are met:
• DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0101, P103, P0121, P0122, P0123, P0131, P0132, P0151,
P0152, P0221, P0222, P0223, P0335, P0336, P0338, P2237, P2240, P2243, P2247, P2251 and P2254 ran and
passed.
• The ignition voltage is 10.0 – 16.0 V.
• The HO2S is at operating temperature.
• The ECM internal sensing element resistance test is enabled.
Condition 2
Run continuously once the following conditions are met:
• DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0101, P103, P0121, P0122, P0123, P0131, P0132, P0151,
P0152, P0221, P0222, P0223, P0335, P0336, P0338, P2237, P2240, P2243, P2247, P2251 and P2254 ran and
passed.
• The ignition voltage is 10.0 – 16.0 V.
• The HO2S is at operating temperature.
• The ECM internal sensing element resistance test is enabled.
• The fuel injectors are not disabled.
• If the engine is operating and the ignition is turned off, the engine must be off for at least 5 minutes for this DTC to
run.
DTC P0137 and P0157
Run continuously once the following conditions are met:
• DTCs P0117, P0118, P0125 and P0128 ran and passed.
• The engine is operating for longer than two minutes.
• The ignition voltage is 10.0 – 16.0 V.
• The HO2S is at operating temperature.

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Engine Management – V6 – Diagnostics Page 6C1-2–86

DTC P2243 and P2247
The ECM detects the internal HO2S signal voltage is not 0.2 – 4.7 V.
DTC P2270 and P2272
W hen the ECM detects the HO2S 2 is less than 650 mV for 100 seconds, the ECM enriches the fuel mixture up to 30
percent for 10 seconds. This DTC sets if the ECM detects the HO2S 2 is still less than 650 mV.
DTC P2271 and P2273
W hen the ECM detects the HO2S 2 is greater than 650 mV for 100 seconds, the ECM leans the fuel mixture up to -7
percent for 10 seconds. If this signal voltage is still greater than 650 mV, the ECM tests the HO2S at the next decel fuel
cut-off. This DTC sets if the ECM detects the HO2S 2 signal voltage is greater than 200 mV after 4 seconds in decel fuel
cu-off mode.
DTC P2297 and P2298
The ECM detects the internal HO2S 1 signal voltage is greater than 3.7 V for longer than 10 seconds.
Conditions for Clearing the DTC
The HO2S reference circuit DTCs are Type B DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for action
taken when Type B DTC sets and conditions for clearing Type B DTCs.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the HO2S system operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• The HO2S must be tightened correctly. A loose HO2S will trigger these DTCs.
• A fault condition in the fuel delivery system, air intake system or exhaust system may trigger these DTCs.
• 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.
• To assist diagnosis, refer to 3 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
DTC P0130 to P0132, P0135 to P0138, P0140, P0141, P0150 to P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270 to P2273, P2297 or P2298 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 Start the engine.
3 Allow the engine to reach the normal operating temperature.
4 Increase the engine speed to 2,000 rpm for 10 seconds or operate the vehicle within the conditions for setting the DTC.
5 Using Tech 2, select the DTC display function.
Does DTC P0130, P0131, P0132, P0135, P0137, P0138, P0140,
P0141, P0150, P0151, P0152, P0155, P0160, P0161, P2243, P2247,
P2270, P2271, P2272, P2273, P2297 or P2298 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 Are DTCs relating to the heater circuit of the O2 sensor, also set?
(e.g. P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051,
P0052, P0056, P0057 or P0058) Go to the
appropriate DTC
Table in this Section Go to Step 4

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Engine Management – V6 – Diagnostics Page 6C1-2–87

Step Action Yes No
4 1 Disconnect the appropriate HO2S wiring connector.
2 Switch on the ignition with the engine not running.
3 Using a digital multimeter, measure the voltage between the HO2S reference signal circuit and low reference circuit.
Does the multimeter display 350 – 550 mV? Go to Step 7 Go to Step 5
5 1 Test the reference signal circuit of the HO2S for a high
resistance, open circuit, short to ground or short to voltage fault
condition. Refer to 8A Electrical - Body and Chassis for
information on electrical fault diagnosis.
W as any fault found and rectified? Go to Step 10 Go to Step 6
6 1 Test the low reference circuit of the HO2S for a high resistance,
open circuit, short to ground or short to voltage fault condition.
Refer to 8A Electrical - Body and Chassis for information on
electrical fault diagnosis.
W as any fault found and rectified? Go to Step 10 Go to Step 9
7 1 Test or inspect for the following conditions that may cause the
HO2S to detect an incorrect air / fuel mixture:
− lean or rich fuel injector fuel delivery,
− restricted air intake system,
− contaminated fuel,
− low fuel line pressure,
− exhaust leak near the HO2S, and
− leak in the crankcase or vacuum line.
W as any fault found and rectified? Go to Step 10 Go to Step 8
8 1 Replace the appropriate HO2S. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
W as the repair completed? Go to Step 10 —
9 1 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 10 —
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 any HO2S reference circuit DTC fail this ignition cycle? Go to Step 2 Go to Step 11
11 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
When all diagnosis and repairs are completed, check the system for correct operation.
7.11 DTC P0133 or P0153
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0133 – HO2S Circuit Slow Response – Bank 1 Sensor 1

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Engine Management – V6 – Diagnostics Page 6C1-2–88

• DTC P0153 – HO2S Circuit Slow Response – Bank 2 Sensor 1
Circuit Description
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides
more information than the switching style HO2S. 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 to
maintain 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 P0133 or P0153 failed, DTCs P0121, P0122, P0123, P0221, P0222, P0223,
P0336, P0338, P2237, and P2240 must run and pass.
• DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0053, P0059, P0130, P0131, P0132, P0135, P0150, P0151,
P0151, P0152, P0155, P0442, P0443, P0446, P0455, P0458, P0459, P0496, P167A, P167B, P2096, P2097,
P2098, P2099, P2231, P2234, P2243, P2247, P2251, P2254, P2297, P2298, P2626, and P2629 are not set.
• The HO2S is at operating temperature.
• The HO2S is between 0.94 – 1.06 lambda.
• The engine speed is between 1,480 – 2,040 rpm.
• The volumetric efficiency is between 16.5 – 38.3 percent.
• The change in volumetric efficiency is less than 3 percent.
• The evaporative emission (EVAP) purge is not active, or the ECM determines the EVAP hydrocarbon (HC)
concentration is less than a predetermined amount when EVAP purge is active.
• The long term fuel trim correction is active.
• DTCs P0133 and P0153 run continuously once the above conditions are met for 10 minutes.
Conditions for Setting the DTC
• The ECM has determined that the dynamic value of the affected HO2S is less than a predetermined threshold.
• The above condition is met for more than 4 seconds.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the
diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic
fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the
second consecutive ignition cycle, the control module records the operating conditions at the time of the failure.
The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
• The ECM turns OFF the malfunction indicator lamp (MIL) after four consecutive ignition cycles that the diagnostic
runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

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