2007 ISUZU KB P190 Engine

Engine Management – V6 – Diagnostics Page 6C1-2–78

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 any of the ECT sensor DTCs 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.
7.9 DTC P0121, P0122, P0123, P0221,
P0222,or P0223
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0121 – Throttle Position Sensor 1 Circuit Range / Performance
• DTC P0122 – Throttle Position Sensor 1 Circuit Low Voltage
• DTC P0123 – Throttle Position Sensor 1 Circuit High Voltage
• DTC P0221 – Throttle Position Sensor 2 Circuit Range / Performance
• DTC P0222 – Throttle Position Sensor 2 Circuit Low Voltage
• DTC P0223 – Throttle Position Sensor 2 Circuit High Voltage
Circuit Description
The ECM applies 5 V to the throttle position (TP) sensor 1 through the 5 V reference circuit and the ground through the
low reference circuit. TP sensor 1 and TP sensor 2 share common 5 V reference circuit and low reference circuit.
The TP sensor 1 and TP sensor 2 have individual signal circuits with opposite functionality. These signal circuits provide
the ECM with a signal voltage that is proportional to the throttle plate movement.
• The TP sensor 1 signal voltage is less than 1 V when the throttle plate is in closed position, which increases to
greater than 4 V when the throttle plate is moved to wide-open throttle.
• The TP sensor 2 signal voltage is greater than 4 V when the throttle plate is in closed position, which decreases to
less than 1 V when the throttle plate is moved to wide-open throttle.
The ECM monitors and compares the TP sensor 1 signal voltage to the TP sensor signal voltage 2. In addition, the ECM
compares the TP sensor signal to the MAF sensor signal to determine a calculated TP sensor signal.
A TP sensor DTC sets if the ECM detects a fault condition in the TP sensor signal output.
Conditions for Running the DTC
DTC P0121 runs continuously once the following conditions are met:
• The ignition voltage is greater than 7 V.
• The TP sensor 1 signal voltage is 0.17 – 4.6 V.
DTC P0122, P0123, P0222 and P0223 runs continuously once the following conditions are met:
• The ignition voltage is greater than 7 V.
• The ignition is switched on.
DTC P0221 runs continuously once the following conditions are met:
• The battery voltage is greater than 7 V.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

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.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

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

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

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)

BACK TO CHAPTER INDEX
TO MODEL INDEX
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

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

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.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–84

• The calculated exhaust temperature is 250ºC – 800ºC.
• The engine coolant temperature is less than 40ºC at start-up and greater than 60ºC when the ignition was turned
off last ignition cycle.
• The fuel tank level is greater than 25 percent.
DTC P0138 and P0158
Run continuously once the following conditions are met:
• The engine is operating for longer than two minutes.
• The ignition voltage is 10.0 – 16.0 V.
• The HO2S is at operating temperature.
• The calculated exhaust temperature is 250ºC – 800ºC.
DTC P0140 and P0160
Run continuously once the following conditions are met for longer than 90 seconds:
• The engine is operating.
• The ignition voltage is 10.0 – 16.0 V.
• The calculated exhaust temperature is 250º C – 800º C.
DTC P0141 and P0161
Run continuously once the following conditions are met:
• DTCs P0036, P0037, P0038, P0056, P0057, and P0058 ran and passed.
• DTCs P0137, P0138, P0140, P0157, P0158, or P0160 are not set.
• The engine is operating.
• The ECM internal sensing element resistance is valid.
• The fuel system is not in decel fuel shut-off.
• The intake air temperature is greater than -7ºC.
• 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.
• The ignition voltage is 10.0 – 16.0 V.
• The calculated exhaust temperature is 360ºC – 500ºC.
DTC P2243 and P2247
Run continuously once the following conditions are met:
• DTCs P0030, P0031, P0032, P0050, P0051 and P0052 ran and passed.
• The ECM internal sensing element resistance is greater than 570 Ω.
• The HO2S is at operating temperature.
DTC P2270 and P2272
Run continuously once the following conditions are met:
• DTCs P0036, P0037, P0038, P0056, P0057, P0058, P0137, P0138, P0140, P0141, P0157, P0158, P0160, P0161,
P0342, P0343, P0443, P0458 and P0459 ran and passed.
• The engine is running.
• The HO2S 2 are at operating temperature for longer than 10 seconds.
• The long term fuel control is enabled.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–85

• The MAF sensor is greater than 10 g/s.
DTC P2297 and P2298
Condition 1
Run continuously once the following conditions are met:
• DTCs P0130 and P0150 ran and passed.
• The HO2S 1 are at operating temperature.
• The desired HO2S 1 signal is less than 1.6 lambda.
• The internal ECM HO2S 1 signal voltage is less than 4.81 V.
• The fuel injectors are enabled.
Condition 2
Run continuously once a decel fuel cut-off has occurred 11 times with successful adjustments
Conditions for Setting the DTC
DTC P0130 and P0150
The ECM detects the HO2S signal voltage is out of range.
DTC P0131 and P0151
The ECM internal HO2S voltage is less than the specified threshold.
DTC P0132 and P0152
The ECM internal HO2S voltage is less than the specified threshold.
DTC P0135 and P0155
Condition 1
The ECM internal HO2S sensing element resistance is less than the specified threshold for longer than 15 seconds.
Condition 2
The ECM detects the calculated HO2S temperature is greater than a predetermined threshold.
DTC P0137 and P0157
The ECM detects the HO2S signal voltage is less than 60 mV.
DTC P0138 and P0158
The ECM detects the HO2S signal voltage is greater than 1050 mV.
DTC P0140 and P0160
The ECM detects one of the following conditions:
• The HO2S signal voltage is 400 – 500 mV for longer than 5 minutes, or
• the internal resistance of the HO2S is greater than 40,000 Ω when the calculated exhaust temperature is greater
than 600ºC.
DTC P0141 and P0161
The ECM detects the HO2S internal resistance is not within the expected range for longer than 6 seconds.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007