2007 ISUZU KB P190 Wiring harness

Battery Page 6D1-3–7

3 Diagnosis
3.1 Diagnostic Procedures
Introduction
This test is used to aid in diagnosing faults with the vehicle where the battery seems to be at fault.
W ith the increased use of electronic sensors and computer control, the battery is much more than just a component used
to start a car. Low battery voltage can:
• affect the operation of the vehicle control modules and cause driveability problems, and
• cause the control modules to set diagnostic trouble codes (DTCs).
For example if a control module senses low battery voltage, it may increase fuel injector timing to increase engine rpm to
increase the generator output.
Therefore consider the state of charge of the battery any time a customer complains of a driveability related problem.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
1 Checks the operator understands the safety precautions for working with batteries.
2 Checks if the vehicle is fitted with a battery of the correct specification.
3 Checks if the battery appears serviceable by performing the battery inspection procedure.
4 Checks if the battery loses charge over an extended period. If so the likely problem is excess current draw while the vehicles ignition is in the off position.
5 Checks the state of charge of the battery.
6 Checks if the battery is capable of delivering the required load by performing the load test procedure.
Diagnostic Table Notes
1 For all wiring harness fault diagnosis, refer to 8A Electrical Body & Chassis.
2 For wiring harness repairs, refer to 8A Electrical Body & Chassis.
3 Refer to 6D1 – 3 Battery – V6.
Diagnostic Table
Step Action Yes No
1
Have you read and understood the safety precautions for working with
batteries? Go to Step 2 Refer to 2
Safety Precautions
2 Check the battery fitted is the correct specification recommended for
the vehicle? Refer to 5 Specifications.
Is the battery the correct specification? Go to Step 3 Replace the battery
with the correct
specification
3 Perform the battery inspection, refer to 3.2 Battery Inspection.
Does the battery appear serviceable? Go to Step 4 Replace the battery,
refer to 4.1
Battery
4 Does the customer complain the battery loses charge if the engine is
not started for an extended period? Preform the battery
current draw test, refer to 3.5
Battery
Current Draw Test Go to Step 5

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ISUZU KB P190 2007

Battery Page 6D1-3–13

3 W hen the circuit group is determined, install the fuse / circuit breaker and identify the specific circuit within this
group that is drawing the excess current. Disconnect the wiring harness connectors in this circuit group one at a
time. Refer to 8A Electrical Body & Chassis.
4 W hen the cause is disconnected, the multimeter reading should drop to the correct reading as outlined in Step 9 of the Test Procedure in this Section.
5 If required, remove the components in this circuit one at a time to determine the cause of the excessive standing current. Refer to 8A Electrical Body & Chassis.
6 Repair the fault, refer to 8A Electrical Body & Chassis.
7 Ensure any fuses, circuit breakers and connectors that have been removed are secure.
Restore
1 Reconnect the electrical earth cable to the battery terminal and tighten the nut to the correct torque specification.
Battery terminal nut
torque specification .....................................2.0 – 5.0 Nm
2 Disconnect the multimeter connections.

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ISUZU KB P190 2007

Powertrain Interface Module – V6 Page 6E1–16

Tech 2 PIM Diagnostic Tests
Tech 2 Limitations
Some DTCs trigger other DTCs to set, which causes Tech 2 to display multiple DTCs. In those situations, Tech 2 may
display more DTCs than is needed to rectify a fault.
W hen Tech 2 displays an output function, it displays only the command given by the PIM. If a connector is disconnected,
that fault will not register in the PIM output function. Tech 2 does not verify the command action.
The service technician must understand the system being diagnosed as well as the correct use and limitations of Tech 2
to be able to perform diagnostic procedures efficiently and successfully.
Tech 2 Intermittent Fault Tests
The following are lists of Tech 2 diagnostic tests that may be used to diagnose intermittent faults:
• W iggle test the suspected PIM wiring harness and connector while observing Tech 2 operating parameters of the
circuit being tested. If Tech 2 read-out fluctuates during this procedure, check the wiring harness circuit for loose
connection.
• Road test the vehicle in conditions that trigger the intermittent fault while an assistant observes the suspected Tech
2 operating parameter data.
• Capture and store data in the Snapshot mode when the fault occurs. The stored data may be replayed at a slower
rate to aid in diagnostics. Refer to Tech 2 User Instructions for more information on the Snapshot function.
• Operate suspected components to test their operation using Tech 2 Output Control Data.

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ISUZU KB P190 2007

Powertrain Interface Module – V6 Page 6E1–25

• Thorough inspection of the wiring circuits and connectors listed in the diagnostic procedures must be performed,
otherwise misdiagnosis may occur.
• Inspect the electrical circuitry or connector terminals that are suspected to be causing the complaint for the
following conditions:
• backed-out connector terminals,
• improper wiring connector mating,
• broken wiring connector locks,
• damaged connector terminals, and
• physical damage to the wiring harness.
• Before replacing a component, inspect its connector terminal for corrosion or deformation that may cause the fault
condition.
Preliminary Checks
The PIM preliminary check examines easily accessible components which may cause problems with the PIM. This visual
and physical inspection procedure may quickly identify the fault condition and eliminate the need for additional diagnosis.
• Refer to Service Techlines for relevant information regarding the fault condition.
• Ensure the battery is fully charged.
• Check the battery connections for corrosion or a loose terminal.
• Perform a visual and physical inspection of the following:
• PIM component wiring harness and terminals for proper connections, pinches or cuts, and
• PIM wiring harness routing which may be positioned very close to a high voltage or high current devices such
as aftermarket audio systems.
NOTE
High voltage or high current devices may induce
electrical noise on a circuit, which can interfere
with normal circuit operation.
• The PIM is sensitive to Electro Magnetic Interference (EMI). Check for incorrect aftermarket theft deterrent
devices, lights or mobile phone installations if an intermittent malfunction is suspected.
7.2 Diagnostic System Check
Step Action Yes No
1
Have you met the basic diagnostic requirements listed in the PIM
Diagnostic Starting Point?
Go to Step 2 Refer to
7.1 Diagnostic
Requirements,
Precautions and
Preliminary Checks
2 Have you read the Diagnostic Precautions?
Go to Step 3 Refer to
7.1 Diagnostic Requirements,
Precautions and
Preliminary Checks
3 Have you performed the Preliminary Checks?
Go to Step 4 Refer to
7.1 Diagnostic Requirements,
Precautions and
Preliminary Checks

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Powertrain Interface Module – V6 Page 6E1–27

7.3 Powertrain Interface Module – Module
Communication Check Failure
Diagnostic Table
Step Action Yes No
1
Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
7.2 Diagnostic System Check
2 Test the following PIM circuits for a high resistance, open circuit or
short to ground fault condition. Refer to 8A Electrical - Body and
Chassis for information on electrical diagnosis:
• 12 V battery supply circuit,
• 12 V ignition circuit, and
• ground circuit.
Has any fault been found and rectified? Go to Step 10 Go to Step 3
3 1 Disconnect the ECM harness connector.
2 Switch off the ignition for 10 seconds.
3 Using Tech 2, attempt to communicate with the PIM.
NOTE
Other DTCs may set when the ECM connector is
disconnected and the ignition is switched on. Disregard
DTCs that set under this condition on this DTC Table.
Does Tech 2 communicate with the PIM? Go to Step 4 For vehicles with
automatic
transmissions, go to
Step 5. For vehicles with manual
transmission go to Step 8
4 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
Has the repair been completed? Go to Step 10 —
5 1 Disconnect the TCM harness connector.
2 Switch off the ignition for 10 seconds.
3 Using Tech 2, attempt to communicate with the PIM.
Does Tech 2 communicate with the PIM? Go to Step 6 Go to Step 8
6 Test serial data circuits between the TCM and ECM for a short to
voltage, short to ground or short together condition.
Has any fault been found and rectified? Go to Step 10 Go to Step 7
7 Replace the TCM. Refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing.
Has the repair been completed? Go to Step 10 —
8 Test serial data circuits between the PIM and ECM for vehicles with
manual transmission, or between the PIM and TCM for vehicles with
automatic transmission for a high resistance or open circuit fault
condition. Refer to 8A Electrical - Body and Chassis for information on
wiring circuit testing and repair.
Has any fault been found and rectified? Go to Step 10 Go to Step 9
9 Replace the PIM. Refer to 11.2 Powertrain Interface Module.
Has the repair been completed? Go to Step 10 —
10 Using Tech 2, attempt to communicate with the PIM.
Does Tech 2 communicate with the PIM? Go to Step 11 Refer to
7.2 Diagnostic System Check

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Powertrain Interface Module – V6 Page 6E1–34

Step Action Yes No
2
1 Switch off the ignition for 10 seconds.
2 Operate the vehicle within the conditions for setting DTC U2100.
3 Using Tech 2, select the DTC display function.
Does DTC U2100 fail this ignition cycle? Go to Step 3 Refer to
Additional
Information in this
Section
3 1 Disconnect the ECM harness connector.
2 Switch off the ignition for 10 seconds.
3 Operate the vehicle within the conditions for setting DTC U2100.
4 Using Tech 2, select the DTC display function and check if DTC U2100 fails this ignition cycle.
NOTE
Other DTCs may set when the ECM connector is
disconnected and the ignition is switched on. Disregard
DTCs that set under this condition on this DTC Table.
Does DTC U2100 fail this ignition cycle? For vehicles with
automatic
transmissions, go to Step 5. For vehicles
with manual
transmission go to Step 8 Go to Step 4
4
Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
Has the repair been completed? Go to Step 11 —
5 1 Disconnect the TCM harness connector.
2 Switch off the ignition for 10 seconds.
3 Using Tech 2, attempt to communicate with the PIM.
Does Tech 2 communicate with the PIM? Go to Step 6 Go to Step 8
6 Test serial data circuits between the TCM and ECM for a short to
voltage, short to ground or short together condition. Refer to 8A
Electrical - Body and Chassis for information on wiring circuit testing
and repair.
Has any fault been found and rectified? Go to Step 11 Go to Step 7
7
Replace the TCM. Refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing
Has the repair been completed?. Go to Step 11 —
8 Test serial data circuits between the PIM and ECM for vehicles with
manual transmission, or between the PIM and TCM for vehicles with
automatic transmission for a high resistance or open circuit fault
condition. Refer to 8A Electrical - Body and Chassis for information on
wiring circuit testing and repair.
Has any fault been found and rectified? Go to Step 11 Go to Step 9
9 Test serial data circuits and between the PIM and the data link
connector for a short to voltage, short to ground or short together
condition. Refer to 8A Electrical - Body and Chassis for information on
wiring circuit testing and repair.
Has any fault been found and rectified? Go to Step 11 Go to Step 10
10
Replace the PIM. Refer to 11.2 Powertrain Interface Module.
Has the repair been completed? Go to Step 11 —

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ISUZU KB P190 2007

Powertrain Interface Module – V6 Page 6E1–37

Step Action Yes No
6
1 Disconnect the PIM harness connector (vehicles with manual
transmission), or TCM harness connector (vehicles with
automatic transmission).
2 Using a digital multimeter, measure the resistance between the two CAN_LO terminals of either the PIM or TCM.
NOTE
Refer to 5 GM LAN Serial Communication Circuit and
6 Wiring Diagram and Connector for the appropriate GM
LAN component terminal identification.
Does the digital multimeter display infinity? Go to Step 8 Go to Step 7
7
Using a digital multimeter, measure the resistance between the two
CAN_HI terminals of either the PIM (vehicles with manual
transmission) or TCM (vehicles with automatic transmission).
Does the digital multimeter display infinity? Go to Step 8 Go to Step 9
8
Replace the PIM (vehicles with manual transmission) or TCM
(vehicles with automatic transmission). Refer to one of the following
for the component replacement procedure:
• 7C4 Automatic Transmission – 4L60E – On-vehicle Servicing, or
• 11.2 Powertrain Interface Module.
Has the repair been completed? Go to Step 11 —
9 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
Has the repair been completed? Go to Step 11
—
10
Replace the PIM. Refer to 11.2 Powertrain Interface Module.
Has the repair been 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 DTC U2105 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 System OK
When all diagnosis and repairs are completed, clear all DTCs and check the system for correct operation.

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Powertrain Interface Module – V6 Page 6E1–39

6 This step tests the internal GM LAN CAN_HI circuit in the PIM.
7 This step tests the internal GM LAN CAN_LO circuit in the PIM.
DTC U2106 Diagnostic Table
Step Action Yes No
1
Has the Diagnostic System Check been performed?
Go to Step 2 Refer to
7.2 Diagnostic
System Check
2 1 Switch off the ignition for 10 seconds.
2 Operate the vehicle within the conditions for setting DTC U2106.
3 Using Tech 2, select the DTC display function.
Does DTC U2106 fail this ignition cycle? Go to Step 3 Refer to
Additional
Information in this Section
3 Using Tech 2, attempt to communicate with the TCM.
Does Tech 2 communicate with the TCM? Go to Step 9 Go to Step 4
4 Test the following TCM circuits for a high resistance, open circuit or
short to ground fault condition. Refer to 8A Electrical - Body and
Chassis for information on electrical diagnosis:
• 12 V battery supply voltage circuit,
• 12 V accessory supply circuit,
• Ignition Control Relay 12 V supply circuit, and
• all TCM ground connections.
Has any fault been found and rectified? Go to Step 10 Go to Step 5
5 Test serial data circuits between the TCM and PIM for a high
resistance or open circuit fault condition. Refer to 8A Electrical - Body
and Chassis for information on wiring circuit testing and repair.
Has any fault been found and rectified? Go to Step 10 Go to Step 6
6 1 Disconnect the PIM harness connector.
2 Using a digital multimeter, measure the resistance between the two CAN_LO terminals of the PIM.
NOTE
Refer to 5 GM LAN Serial Communication Circuit and
6 Wiring Diagram and Connector for the appropriate GM
LAN component terminal identification.
Does the digital multimeter display infinity? Go to Step 9 Go to Step 7
7
Using a digital multimeter, measure the resistance between the two
CAN_HI terminals of the PIM.
Does the digital multimeter display infinity? Go to Step 9 Go to Step 8
8
Replace the TCM. Refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing.
Has the repair been completed? Go to Step 10 —
9 Replace the PIM. Refer to 11.2 Powertrain Interface Module.
Has the repair been completed? Go to Step 10 —

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