Isuzu N-Series. Manual - part 771

 Engine Control System (4JH1)    6E-135

18

1.

Reconnect all previously disconnected fuse or
harness connector(s).

2.

Clear the DTCs with the Tech 2.

3.

Turn OFF the ignition for 30 seconds.

4.

Drive the vehicle.

5.

Observe the Vehicle Speed parameter with
the Tech 2.

Does the Vehicle Speed parameter indicate correct
vehicle speed?

—

Go to Step 19

Go to Step 3

19

Observe the DTC Information with the Tech 2.

Are there any DTCs that you have not diagnosed?

—

Go to Diagnostic 

Trouble Code (DTC) 

List

System OK

Step

Action

Value(s)

Yes

No

6E-136    Engine Control System (4JH1) 

P0560 (Symptom Code 1) (Flash Code 35)

Circuit Description
The engine control module (ECM) monitors the system
voltage on the ECM main relay load supply voltage
terminal to make sure that the voltage stays within the
proper range.  If the ECM detects an excessively high
system voltage, this DTC will set.

Condition for Setting the DTC

• The ECM detects that the battery voltage feed

circuit voltage is more than 20 volts.

Action Taken When the DTC Sets

• The ECM does not illuminate the malfunction

indicator lamp (MIL) when the diagnostic runs and
fails.

Condition for Clearing the DTC

• A history DTC clears after 40 consecutive driving

cycles without a fault.  Or clear with the Tech 2.

Diagnostic Aids

• A charging system problem may set this DTC.
• Jump starting the vehicle or a battery charger may

have set this DTC.

DTC P0560 (Symptom Code 1) (Flash Code 35)
Schematic Reference: Engine Controls Schematics &
Starting and Charging Schematics

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check –
Engine Controls?

—

Go to Step 2

Go to Diagnostic 

System Check – 

Engine Controls

2

1.

Install the Tech 2.

2.

Turn OFF the ignition for 30 seconds.

3.

Start the engine.

4.

Monitor the Diagnostic Trouble Code (DTC)
Information with the Tech 2.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Diagnostic 

Aids

3

Was the vehicle recently jump started from 24 volts
system?

—

Go to Step 8

Go to Step 4

4

1.

Start the engine and let idle for 30 seconds.

2.

Observe the System Voltage parameter with
the Tech 2.

Is the System Voltage parameter less than the
specified value?

16 volts

Go to Diagnostic 

Aids

Go to Step 5

5

Test the charging system.  Refer to Diagnosis of
The Charging System in the Charging System
Section.

Did you find a charging system problem?

—

Go to Step 6

Go to Step 7

6

Repair the charging system.  Refer to Diagnosis of
The Charging System in the Charging System
Section.

Did you complete the repair?

—

Go to Step 8

—

7

Important:
Replacement ECM must be programmed.

Replace the ECM.  Refer to Engine Control Module
(ECM) Replacement in this section.

Did you complete the replacement?

—

Go to Step 8

—

 Engine Control System (4JH1)    6E-137

8

1.

Reconnect all previously disconnected
harness connector(s).

2.

Clear the DTCs with the Tech 2.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

5.

Observe the System Voltage parameter with
the Tech 2.

Is the System Voltage parameter less than the
specified value?

16 volts

Go to Step 9

Go to Step 5

9

Observe the DTC Information with the Tech 2.

Are there any DTCs that you have not diagnosed?

—

Go to Diagnostic 

Trouble Code (DTC) 

List

System OK

Step

Action

Value(s)

Yes

No

6E-138    Engine Control System (4JH1) 

P0560 (Symptom Code 2) (Flash Code 35)

Circuit Description
The engine control module (ECM) monitors the system
voltage on the ECM main relay load supply voltage
terminal to make sure that the voltage stays within the
proper range.  If the ECM detects an excessively low
system voltage, this DTC will set.

Condition for Setting the DTC

• The ECM detects that the battery voltage feed

circuit voltage is less than 7 volts.

Action Taken When the DTC Sets

• The ECM does not illuminate the malfunction

indicator lamp (MIL) when the diagnostic runs and
fails.

Condition for Clearing the DTC

• A history DTC clears after 40 consecutive driving

cycles without a fault.  Or clear with the Tech 2.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• A charging system problem may set this DTC.

DTC P0560 (Symptom Code 2) (Flash Code 35)
Schematic Reference: Engine Controls Schematics &
Starting and Charging Schematics
Connector End View Reference: Engine Control
Module (ECM) Connector End Views

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check –
Engine Controls?

—

Go to Step 2

Go to Diagnostic 

System Check – 

Engine Controls

2

1.

Install the Tech 2.

2.

Turn OFF the ignition for 30 seconds.

3.

Start the engine.

4.

Monitor the Diagnostic Trouble Code (DTC)
Information with the Tech 2.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Diagnostic 

Aids

3

1.

Start the engine and let idle for 30 seconds.

2.

Load the electrical system by turning ON the
headlights, A/C, etc.

3.

Observe the System Voltage parameter with
the Tech 2.

Is the System Voltage parameter more than the
specified value?

10 volts

Go to Diagnostic 

Aids

Go to Step 4

4

Test the charging system.  Refer to Diagnosis of
The Charging System in the Charging System
Section.

Did you find a charging system problem?

—

Go to Step 5

Go to Step 6

5

Repair the charging system.  Refer to Diagnosis of
The Charging System in the Charging System
Section.

Did you complete the repair?

—

Go to Step 8

—

6

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent, for a poor
connection and corrosion on the battery
voltage feed at the harness connector of the
ECM (pin 3 of B-234 connector).

4.

Repair or clean the connection(s) as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7