2007 ISUZU KB P190 check engine

Engine Management – V6 – Diagnostics Page 6C1-2–181

Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the TP sensor operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• 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 P2107 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 Operate the vehicle within the conditions for running the DTC.
3 Using Tech 2, select the DTC display function.
Does DTC P2107 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 4 —
4 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 P2107 fail this ignition cycle? Go to Step 2 Go to Step 5
5 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.
7.50 DTC P2122, P2123, P2127, P2128 or
P2138
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P2122 – Accelerator Pedal Position Sensor 1 Voltage Low
• DTC P2123 – Accelerator Pedal Position Sensor 1 Voltage High
• DTC P2127 – Accelerator Pedal Position Sensor 2 Voltage Low
• DTC P2128 – Accelerator Pedal Position Sensor 2 Voltage High
• DTC P2138 – Accelerator Pedal Position Sensor 1 – 2 Correlation
Circuit Description
The ECM applies a separate 5 V reference circuit and low reference circuit to the accelerator pedal position (APP)
sensor 1 and sensor 2. The APP sensors produce a signal voltage that represents the accelerator pedal position.

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Engine Management – V6 – Diagnostics Page 6C1-2–183

DTC P2122, P2123, P2127, P2128 or P2138 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 P2122, P2123, P2127, P2128 or P2138 fail this ignition
cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Disconnect the APP sensor wiring connector.
2 Switch on the ignition with the engine not running.
3 Using a digital multimeter, measure the voltage between the 5 V reference circuit of the appropriate APP sensor and the ECM
housing.
Does the multimeter display 4.8 – 5.2 V? Go to Step 4 Go to Step 6
4 1 Connect a 3 A fused jumper wire between the 5 V reference
circuit and the signal circuit of the appropriate APP sensor.
2 Switch on the ignition with the engine not running.
3 Using Tech 2, observe the voltage parameter appropriate APP sensor.
Does Tech 2 display 4.8 – 5.2 V ?
Go to Step 5 Go to Step 7
5 1 Switch off the ignition.
2 Remove ECM / TCM Fuse 29 from the engine compartment fuse and relay panel assembly.
3 Using a DMM, measure the resistance between the appropriate 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 this test.
Does the multimeter display 5 Ω? Go to Step 9 Go to Step 8
6 Test the 5 V reference circuit of the appropriate APP sensor 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 11 Go to Step 10
7 Test the signal circuit of the appropriate APP sensor 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 11 Go to Step 10
8 Test the low reference circuit of the appropriate APP sensor 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 11 Go to Step 10

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–184

Step Action Yes No
9 Replace the accelerator pedal assembly. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
W as the repair completed? Go to Step 11 —
10 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 11 —
11 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 APP Sensor Circuit DTCs fail this ignition cycle? Go to Step 2 Go to Step 12
12 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.
7.51 DTC P2177 or P2179
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P2177 Fuel Trim System Lean at Cruise or Accel Bank 1
• DTC P2179 Fuel Trim System Lean at Cruise or Accel Bank 2
Circuit Description
The engine control module (ECM) controls the air / fuel metering system to provide the best possible combination of
driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop.
During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S)
input. During Closed Loop, the HO2S inputs are added and used by the ECM to calculate short and long term fuel trim
fuel delivery adjustments. If the HO2S indicate a lean condition, fuel trim values will be above 0 percent. If the HO2S
indicate a rich condition, fuel trim values will be below 0 percent. Short term fuel trim values change rapidly in response
to the HO2S signals. Long term fuel trim makes coarse adjustments to maintain an air / fuel ratio of 14.7:1. If the ECM
detects an excessively lean condition, this DTC sets.
Conditions for Running the DTC
• Before the ECM can report DTC P2177 or P2179 failed, DTCs P0101, P0121, P0122, P0123, P0133, P0153,
P0221, P0222, P0223, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2066, P2067, and P2068
must run and pass.
• The fuel system is in closed loop.
• The long fuel trim is active.
• The engine coolant temperature (ECT) is more than 60° C.
• The evaporative emission (EVAP) canister purge solenoid valve is not enabled.
• The intake air temperature (IAT) is less than 60° C.
• The fuel level is more than 11.6 percent.
• The amount of air flow into the engine is more than 7,000 grams.
• DTC P2177 and P2179 runs continuously once the above conditions are met for at least 300 seconds.

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Engine Management – V6 – Diagnostics Page 6C1-2–185

Conditions for Setting the DTC
• The Total Fuel Trim Avg. is more than 23 percent.
• The condition exists for 4 seconds.
Action Taken When the DTC Sets
• The control module 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 control module 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.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission
related diagnostic.
• Use Tech 2 to clear the MIL and the DTC.
Additional Information
• A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a lean condition.
• Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum
leaks.
• 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.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2 This step determines if there is a current condition.
4 If DTC P2177 and P2179 are set at the same time, this indicates that both banks of the engine are operating lean. Inspect for items that would cause both banks of the engine to operate lean.
5 Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. A MAF sensor
condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor
parameters will appear to be within range.
6 A vacuum leak causes DTC P2177 and P2179 to set at the same time. Inspect all areas of the engine for a vacuum leak. Also inspect the PCV valve for being the correct one for this application. Make sure that the engine
oil fill cap is in place and that it is tight. Verify that the engine oil dip stick is fully seated.
DTC P2177 or P2179 Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been completed? —
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–186

2 NOTE
If any DTCs are set, except P2177 or
P2179, refer to those DTCs before
proceeding with this diagnostic.
1 Idle the engine at the normal operating temperature.
2 Check that the fuel system is operating in Closed Loop.
3 Observe the Total Fuel Trim Avg. parameter for bank 1 or bank 2 with a scan tool.
Is the Total Fuel Trim Avg. less than the specified
value indicated? 23%
Go to Step 3 Go to Step 4
3 1 Use Tech 2 to clear the DTC/s.
2 Ignition OFF for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the Conditions for Running the DTC.
Does the DTC fail this ignition cycle? —
Go to Step 4 Refer to Additional
Information in this DTC
4 Are both banks of the engine operating lean? —
Go to Step 5 Go to Step 7
5 1 Start the engine.
NOTE
Additional DTCs will set when the MAF
sensor 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, using 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 P0103in this Section Go to Step 6

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Engine Management – V6 – Diagnostics Page 6C1-2–189

• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• 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.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2 This step determines whether the fault is present.
4 If DTC P2178 and DTC P2180 set at the same time, then both banks of the engine are operating rich. Inspect items that would cause both banks of the engine to operate rich.
5 Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. A MAF sensor
condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor
parameters will appear to be within range.
DTC P2178 or P2180 Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been completed? —
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 NOTE
If any DTCs are set, except P2178 and
DTC P2180, refer to those DTCs before
proceeding with this diagnostic.
1 Idle the engine at the normal operating temperature.
2 Check that the fuel system is in Closed Loop.
3 Observe the Total Fuel Trim Avg. parameter for bank 1 and / or bank 2 with Tech 2.
Is the Total Fuel Trim Avg. less than the specified
value? –22%
Go to Step 3 Go to Step 4
3 1 Observe the Freeze Frame and / or the Failure
records data for this DTC.
2 Turn the ignition OFF for 30 seconds.
3 Start the engine.
4 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 and / or the Failure
records data.
Does the DTC fail this ignition cycle? —
Go to Step 4 Refer to Additional
Information in this DTC.
4 Are both banks of the engine operating rich? —
Go to Step 5 Go to Step 7

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–192

Additional Information
• A fuel delivery condition causes this DTC to set. Thoroughly inspect all items that could cause a rich condition.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• 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.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2 This step determines if there is a current condition.
4 If DTC P2187 and P2189 are set at the same time, this indicates that both banks of the engine are operating lean. Inspect for items that would cause both banks of the engine to operate lean.
5 Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. A MAF sensor
condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor
parameters will appear to be within range.
6 A vacuum leak causes DTC P2187 and P2189 to set at the same time. Inspect all areas of the engine for a vacuum leak. Also inspect the positive crankcase ventilation (PCV) valve for being the correct one for this
application. Make sure that the engine oil fill cap is in place and that it is tight. Verify that the engine oil dip stick is
fully seated.
DTC P2187 or P2189 Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been completed? —
Go to Step 2 Refer to
4.4 Diagnostic
System Check in this Section
2 NOTE
If any DTCs are set, except P2187 and
DTC P2189, refer to those DTCs before
proceeding with this diagnostic.
1 Idle the engine at the normal operating temperature.
2 The fuel system is in Closed Loop.
3 Observe the Total Fuel Trim Avg. parameter for bank 1 and / or bank 2 with a scan tool.
Is the Total Fuel Trim Avg. less than the specified
value? 40%
Go to Step 3 Go to Step 4
3 1 Observe the Freeze Frame and / or the Failure
records data for this DTC.
2 Turn the ignition OFF for 30 seconds.
3 Start the engine.
4 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 and / or the Failure
records data.
Does the DTC fail this ignition cycle? —
Go to Step 4 Refer to Additional
Information in this DTC.
4 Are both banks of the engine operating lean? —
Go to Step 5 Go to Step 7

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Engine Management – V6 – Diagnostics Page 6C1-2–195

Action Taken When the DTC Sets
• The control module activates 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 control module 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.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission
related diagnostic.
• Use Tech 2 to clear the MIL and the DTC.
Additional Information
• A fuel delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich condition.
• 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.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2 This step determines whether the fault is present.
4 If DTC P2188 and P2190 set at the same time, then both banks of the engine are operating rich. Inspect items that would cause both banks to operate rich.
5 Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. A MAF sensor
condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor
parameters will appear to be within range.
DTC P2188 or P2190 Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been completed? —
Go to Step 2 Refer to
4.4 Diagnostic System Check in this Section
2 NOTE
If any DTCs are set, except P2188 and
P2190, refer to those DTCs before
proceeding with this diagnostic.
1 Idle the engine at the normal operating temperature.
2 Check that the fuel system is in Closed Loop.
3 Observe the Total Fuel Trim Avg. parameter for bank 1 and / or bank 2 with Tech 2.
Is the Total Fuel Trim Avg. less than the specified
value? –40%
Go to Step 3 Go to Step 4

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ISUZU KB P190 2007