Isuzu KB P190. Manual — part 857

Engine Management – V6 – Diagnostics

Page 6C1-2–150

DTC P0606

There is an internal ECM circuit fault condition for 6 seconds.

Conditions for Clearing the DTC

The ECM Internal Circuit, Programming or Memory Fault DTCs are Type A DTCs. Refer to 1.4

Diagnostic Trouble

Codes in this Section, for action taken when a Type A DTC sets and conditions for clearing Type A 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.

DTC P0601, P0602, P0604 and P0606 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 P0601, P0602, P0604 or P0606 fail this ignition cycle?

Go to Step 3

Refer to Additional

Information in this

DTC

3

Test all ECM fuses and ground connections. Refer to 8A Electrical -
Body and Chassis.

Was any fault found and rectified?

Go to Step 6

Go to Step 4

4

Attempt to program the ECM.

Was the programming successful?

Go to Step 6

Go to Step 5

5

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

Was the repair completed?

Go to Step 6

—

6

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 ECM internal circuit, programming or memory fault
DTCs fail this ignition cycle?

Go to Step 2

Go to Step 7

7

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.

Engine Management – V6 – Diagnostics

Page 6C1-2–151

7.35 DTC P0615, P0616 or P0617

DTC Descriptors

This diagnostic procedure supports the following DTCs:

•

DTC P0615 – Starter Relay Circuit Malfunction

•

DTC P0616 – Starter Relay Circuit Low Voltage

•

DTC P0617 – Starter Relay Circuit High Voltage

Circuit Description

The engine control relay applies battery voltage to the coil circuit of the starter relay through the ignition circuit. When
the ignition switched is turned to the Start position and all the conditions required to enable an engine cranking is met,
the ECM grounds the starter relay control circuit to activate the starter relay. When active, the starter relay applies
battery voltage to the starter motor solenoid control circuit to operate the starter motor. Refer to 6D1-2 Starting System –
V6 for information on the cranking system operation.

The ECM monitors the control circuit of the starter relay for conditions that are incorrect for the commanded state. A
starter relay control circuit DTC sets if the ECM detects a fault condition in the starter relay control circuit.

Conditions for Running the DTC

DTCs P0615, P0616 and P0617 run continuously once the following conditions are met:

•

The ignition is switched on

•

The ignition voltage is 10.0 – 16.0 V.

Conditions for Setting the DTC

The ECM detects a condition that is incorrect for the starter relay commanded state.

Conditions for Clearing the DTC

The starter relay control circuit DTCs are Type C DTCs. Refer to 1.4

Diagnostic Trouble Codes in this Section, for

action taken when Type C DTCs set and conditions for clearing Type C DTCs.

Additional Information

•

Refer to 6D1-2 Starting System – V6 for information on the cranking system 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

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 number in the diagnostic table:

3

A fault condition in the starting system or immobiliser system may trigger this DTC.

DTC P0615, P0616 or P0617 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

Engine Management – V6 – Diagnostics

Page 6C1-2–152

Step Action

Yes

No

2

1

Switch off the ignition for 30 seconds.

2

Turn the ignition switch to the Start position or operate the
vehicle within the conditions for running the DTC.

3

Using Tech 2, select the DTC display function.

Does DTC P0615, P0616 and P0617 fail this ignition cycle?

Go to Step 3

Refer to Additional

Information in this

DTC

3

Check for a fault condition in the following systems which can disable
the starting system:

•

Starting System, refer to 6D1-2 Starting System – V6.

•

Immobiliser System, refer to 11A Immobiliser.

Was any fault found and rectified?

Go to Step 10

Go to Step 4

4

1

Remove the starter relay. Refer to 8A Electrical - Body and
Chassis.

2

Connect a test lamp between the ignition circuit of the starter
relay and a good ground.

3

Switch on the ignition.

Does the test lamp illuminate when the ignition switch is turned to the
on position?

Go to Step 5

Go to Step 6

5

1

Connect a test lamp between the control circuit of the starter
relay and a 12 V.

2

Turn the ignition switch to the Start position and then release it
back to the on position.

Does the test lamp turn on when the ignition switch is turned to the
Start position and then turn off when the ignition switch returns to the
on position?

Go to Step 8

Go to Step 7

6

Repair the ignition voltage circuit of the starter relay for a high
resistance or open circuit fault condition. Refer to 8A Electrical - Body
and Chassis for information on electrical wiring repair procedures.

Was the repair completed?

Go to Step 10

—

7

Test the control circuit of the starter relay for a high resistance, open
circuit, short to ground or a short to voltage fault condition. Refer to
8A Electrical - Body and Chassis for information on electrical fault
diagnosis.

Was any fault found and rectified?

Go to Step 10

Go to Step 9

8

Replace the starter relay. Refer to 8A Electrical - Body and Chassis.

Was the repair completed?

Go to Step 10

—

9

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

Was the repair completed?

Go to Step 10

—

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 the starter relay control circuit 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

Engine Management – V6 – Diagnostics

Page 6C1-2–153

Step Action

Yes

No

When all diagnosis and repairs are completed, check the system for correct operation.

7.36 DTC P0625 or P0626

DTC Descriptors

This diagnostic procedure supports the following DTCs:

•

DTC P0625 – Alternator F Terminal Low Voltage

•

DTC P0626 – Alternator F Terminal High Voltage

Circuit Description

The voltage regulator within the generator regulates the generator charge output by increasing or decreasing the
generator on time. The generator field (Gen F) duty cycle output signal represents the generator on time. Refer to 6D1-1
Charging System – V6 for details of the charging system operation.

The ECM monitors the Gen F terminal output signal to calculate Gen F duty cycle percentage. This enables the ECM to
provide engine idle compensation based on electrical loads and to detect a fault condition in the generator operation.

A Generator F-terminal circuit DTC sets if the ECM detects the Gen F duty cycle is outside the specified range for a
predetermined set of parameters.

Conditions for Running the DTC

DTC P0625

Runs continuously when the following conditions are met:

•

There is no generator, CKP sensor or CMP sensor DTC set.

•

The engine speed is less than 3000 rpm

•

The generator is not commanded off.

DTC P0626

Runs continuously when the following conditions are met:

•

There is no generator, CKP sensor or CMP sensor DTC set.

•

The ignition is switched on with the engine not running

Conditions for Setting the DTC

DTC P0625

The ECM detects the Gen F Terminal Signal parameter is less than five percent for 15 seconds.

DTC P0626

The ECM detects the Gen F Terminal Signal parameter is greater than five percent for 15 seconds.

Conditions for Clearing DTC

The Generator F-terminal circuit 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

•

For an intermittent fault condition, refer to 5.2

Intermittent Fault Conditions in this Section.

•

Refer to 6C1-1 Engine Management – V6 – General Information for details of the ECM operation.