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Isuzu KB P190. Manual - part 874

Engine Management – V6 – Diagnostics

Page 6C1-2–218

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

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

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

Replace the HO2S. Refer to 6C1-3 Engine
Management – V6 – Service Operations.

Did you complete the replacement?

—

Go to Step 11

—

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

—

Use Tech 2 to clear the DTCs.

Turn OFF the ignition for 30 seconds.

Start the engine.

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

Using Tech 2, select the DTC display function.

Does Tech 2 display any DTCs?

—

Go to the

appropriate DTC

Table in this

Section System

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.

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

Wiring 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:

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

Has the Diagnostic System Check been performed?

Go to Step 2

Refer to

4.4 Diagnostic
System Check in

this Section

Switch off the ignition for 30 seconds.

Operate the vehicle within the conditions for running the DTC.

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

Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.

Was the repair completed?

Go to Step 4

—

Using Tech 2, clear the DTCs.

Switch off the ignition for 30 seconds.

Start the engine.

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

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.

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 With 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.

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.

•

For an intermittent fault condition, refer to 5.2

Intermittent Fault Conditions in this Section.

•

To assist diagnosis, refer to 3

Wiring 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:

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

Has the Diagnostic System Check been performed?

Go to Step 2

Refer to

4.4 Diagnostic

System Check in

this Section

Engine Management – V6 – Diagnostics

Page 6C1-2–221

Step Action

Yes

Switch off the ignition for 30 seconds.

Operate the vehicle within the conditions for running the DTC.

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

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

Are DTCs also set in the PIM?

Refer to 6E1

Powertrain Interface

Module – V6

Go to Step 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

Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing.

Was the repair completed?

Go to Step 7

—

Using Tech 2, clear the DTCs.

Switch off the ignition for 30 seconds.

Start the engine.

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

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 With 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.

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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