2007 ISUZU KB P190 Electrical

Engine Management – V6 – Diagnostics Page 6C1-2–213

Conditions for Clearing the DTC
The HO2S pumping current control 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.
• Inspect the HO2S wiring harness for contact with the exhaust system.
• The HO2S must be tightened correctly. A loose HO2S will 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.
• The following table illustrates the typical voltages for the HO2S circuits:
HO2S Voltages
Conditions: • Ignition ON, Engine OFF
• HO2S Disconnected
HO2S Circuit Voltage
Heater Control 4.6 – 5.0 V
Heater Supply Voltage B+
Reference Voltage 2.6 – 3.1 V
Low Reference 2.2 – 2.7 V
Pump Current Less than 0.5 A
Input Pump Current Less than 0.5 A
Test Description
The following numbers refer to the step numbers in the diagnostic table:
2 W hen performing this test, the HO2S should react immediately.
4 Connecting a jumper wire between the HO2S reference signal circuit and the low reference circuit causes the ECM to apply signal voltage to the pumping current and input pumping current.
DTC P2237, P2238, P2239, P2240 or P2242 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
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.
5 Using Tech 2, select the DTC display function.
Does DTC P2237, P2238, P2239, P2240, P2241,
P2242, fail this ignition cycle? —
Go to Step 3 Refer to Additional
Information in this DTC

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Engine Management – V6 – Diagnostics Page 6C1-2–214

3 Are DTCs relating to the reference circuit of the HO2S
also set?
(e.g. 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) —
Go to the
appropriate DTC Table in this Section Go to Step 4
4 1 Disconnect the appropriate HO2S wiring
connector.
2 Ignition ON, engine OFF.
3 Using a digital multimeter, measure the voltage between the input pump current circuit and a
good ground.
Is the voltage more than the specified value? 50 mV
Go to Step 8 Go to Step 5
5 1 Ignition ON, engine OFF.
2 Using a digital multimeter, measure the voltage between the pump current circuit and a good
ground.
is the voltage display more than the specified value? 50 mV
Go to Step 8 Go to Step 6
6 1 Connect a 3 A fused jumper wire between the
HO2S reference signal circuit and the low
reference circuit.
2 Ignition ON, engine OFF.
3 Using a digital multimeter, measure the voltage between the input pump current circuit and a
good ground.
Is the voltage reading within the specified range? 4.8 – 5.2 V
Go to Step 7 Go to Step 8
7 1 Connect a 3 A fused jumper wire between the
HO2S reference signal circuit and the low
reference circuit.
2 Ignition ON, engine OFF.
3 Using a digital multimeter, measure the voltage between the pump current circuit and a good
ground.
Is the voltage reading within the specified range? 4.8 – 5.2 V
Go to Step 9 Go to Step 10
8 1 Test the input pump current and the pump
current circuit of the HO2S for a high resistance,
open circuit, short to ground, short to voltage or
shorted together 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 12 Go to Step 11
9 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,
• 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 12 Go to Step 10

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–216

• The ignition voltage is between 10.7 – 18.0 volts.
• The fuel system is in fuel shut-off mode.
• The calculated exhaust temperature is less than 750°C.
• The heated oxygen sensors are at operating temperature.
• DTC P2626 and P2629 runs continuously once the above conditions are met.
Conditions for Setting the DTC
• The ECM internal HO2S voltage is more than 4.81 volts.
• The condition exists for more than 4 seconds or 600 seconds if the fuel level is less than 12 percent.
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 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.
• 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
• Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a
component harness connector.
• The lower connector of the ECM is connector A43-X1 and the upper connector of the ECM is connector A43-X2.
Refer to 3 W iring Diagrams and Connector Charts.
• The front wide band sensors do not toggle or switch like a switching HO2S. The front HO2S signals will be
relatively stable for an idling engine.
• 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.
• The following table illustrates the typical voltages for the HO2S circuits:
HO2S Voltages
Conditions: • Ignition ON, Engine OFF
• HO2S Disconnected
HO2S Circuit Voltage
Heater Control 4.6 – 5.0 V
Heater Supply Voltage B+
Reference Voltage 2.6 – 3.1 V

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Engine Management – V6 – Diagnostics Page 6C1-2–218

6 1 Test the pump current circuit of the HO2S for an
open. Refer to 8A Electrical-Body and Chassis.
Did you find and correct the condition? —
Go to Step 11 Go to Step 8
7 1 Test for an intermittent and for a poor connection
at the appropriate HO2S. Refer to 8A Electrical-
Body and Chassis.
Did you find and correct the condition? —
Go to Step 11 Go to Step 9
8 1 Test for an intermittent and for a poor connection
at the engine control module (ECM). Refer to 8A
Electrical-Body and Chassis.
Did you find and correct the condition? —
Go to Step 11 Go to Step 10
9 1 Replace the HO2S. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
Did you complete the replacement? —
Go to Step 11 —
10 1 Replace the ECM. Refer to 6C1-3 Engine
Management –V6 – Service Operations for
details on replacing the ECM.
Did you complete the replacement? —
Go to Step 11 —
11 1 Use Tech 2 to clear the DTCs.
2 Turn OFF the ignition 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 / Failure Records.
Did the DTC fail this ignition? —
Go to Step 2 Go to Step 12
12 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, clear all DTCs and verify correct operation
7.61 DTC U0001
DTC Descriptor
This diagnostic procedure supports DTC U0001 – No Communication with CAN-Bus (High Speed).
Circuit Description
The engine control module (ECM) communicates directly with the control modules connected to the GM LAN serial data
communication circuit through the GM LAN protocol.
However, the immobiliser control unit (ICU) communicates with the ECM using the keyword 2000 protocol. Since the GM
LAN and keyword 2000 protocols are not compatible, a powertrain interface module (PIM) is integrated into the serial
data system to serve as a gateway. This gateway allows communication between the two protocols. Refer to 6E1
Powertrain Interface Module – V6 for further information on the GM LAN serial data communication circuit.
DTC U0001 sets if the ECM detects a fault condition in the serial data communication circuit.
Conditions for Running the DTC
DTC U0001 runs continuously when the following conditions are met:
The ignition voltage is 10.0 – 16.0 V.
The vehicle power mode requires serial data communication.

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Engine Management – V6 – Diagnostics Page 6C1-2–219

Conditions for Setting the DTC
The ECM detects a specified number of transmitted messages are not valid.
Conditions for Clearing the DTC
The Serial Data Communication Circuit DTCs are Type ‘C’ DTCs. 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.
• 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.
Test Description
The following number refers to the step numbers in the diagnostic table:
1 The following tests are included in the Diagnostic System Check.
• Tests the integrity of the GM LAN serial data communication circuit.
• Tests for fault conditions on the vehicle immobiliser system stored in the ICU.
DTC U0001 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 U0001 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 U0001 fail this ignition cycle? Go to Step 2 Go to Step 5
5 Using Tech 2, select the DTC display function.
Are there any DTCs displayed? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–220

7.62 DTC U0101
DTC Description
This diagnostic procedure supports the following DTC:
• DTC U0101 – CAN-Bus No Communication W ith TCM (Transmission Control Module)
Circuit Description
The Engine Control Module (ECM) communicates directly with the control modules connected to the GM LAN serial data
communication circuit through the GM LAN protocol.
However, the immobiliser control unit (ICU) communicates with the ECM using the keyword 2000 protocol. Since the GM
LAN and keyword 2000 protocols are not compatible, a powertrain interface module (PIM) is integrated into the serial
data system to serve as a gateway. This gateway allows communication between the two protocols. Refer to 6E1
Powertrain Interface Module – V6 for further information on the GM LAN serial data communication circuit.
A serial data communication circuit – TCM DTC sets if the ECM detects an invalid signal from the TCM.
Conditions for Running the DTC
DTC U0101 runs continuously when the following conditions are met:
• The ignition is on for longer than 3 seconds.
• The ignition voltage is 10.0 – 16.0 V.
Conditions for Setting the DTC
The ECM did not receive a valid signal from the TCM within the specified time frame.
Conditions for Clearing the DTC
This Serial Data Communication Circuit DTC 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 the conditions required for clearing Type C DTCs.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the ECM operation.
• 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.
Test Description
The following number refers to the step numbers in the diagnostic table:
1 The following tests are included in the Diagnostic System Check.
• Tests the integrity of the GM LAN serial data communication circuit.
• Tests for fault conditions on the vehicle immobiliser system stored in the ICU.
DTC P0864 and U0101 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

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Engine Management – V6 – Diagnostics Page 6C1-2–221

Step Action Yes No
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 U0101 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 Using Tech 2, attempt to communicate with the PIM.
Does the PIM failed to communicate? Refer to the 6E1
Powertrain Interface Module – V6 Go to Step 4
4 Are DTCs also set in the PIM? Refer to 6E1
Powertrain Interface Module – V6 Go to Step 5
5 Are DTCs that may trigger a fault condition in the serial data
communication circuit also set in the TCM? Refer to 7C2
Automatic
Transmission –
4L60E – Electrical Diagnosis Go to Step 6
6 Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing.
W as the repair completed? Go to Step 7 —
7 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 serial data communication circuit – TCM DTCs fail
this ignition cycle? Go to Step 2 Go to Step 8
8 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.
7.63 DTC U0155 or U0423
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC U0155 – CAN-Bus No Communication W ith Gateway
• DTC U0423 – CAN-Bus Invalid Data From Gateway
Circuit Description
The Engine Control Module (ECM) communicates directly with the control modules connected to the GM LAN serial data
communication circuit through the GM LAN protocol.
However, the immobiliser control unit (ICU) communicates with the ECM using the keyword 2000 protocol. Since the GM
LAN and keyword 2000 protocols are not compatible, a powertrain interface module (PIM) is integrated into the serial
data system to serve as a gateway. This gateway allows communication between the two protocols. Refer to 6E1
Powertrain Interface Module – V6 for further information on the GM LAN serial data communication circuit
A PIM serial data communication circuit DTC sets if the ECM detects an invalid signal from the PIM.
Conditions for Running the DTC
DTCs U0155 and U0423 run continuously when the following conditions are met:
• The engine is running.

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Engine Management – V6 – Diagnostics Page 6C1-2–222

• The ignition voltage is 10.0 – 16.0 V.
Conditions for Setting the DTC
The ECM did not receive a valid signal from the PIM within the specified time frame.
Conditions for Clearing the DTC
The PIM serial data communication circuit DTCs are Type C DTCs. 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.
• 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.
Test Description
The following number refers to the step numbers in the diagnostic table:
1 The following tests are included in the Diagnostic System Check.
• Tests the integrity of the GM LAN serial data communication circuit.
• Tests for fault conditions on the vehicle immobiliser system stored in the ICU.
DTC U0155 or U0423 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 U0155, or U0423 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this Section
3 Replace the PIM. Refer to 6E1 Powertrain Interface Module – V6.
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 any of the PIM serial data communication circuit DTCs 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.

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ISUZU KB P190 2007