Isuzu N-Series. Service manual - part 693

6E-194    Engine Control System (4HK1) 

P0606 (Flash Code 51, 52)

Circuit Description
This diagnostic applies to internal microprocessor
integrity conditions within the engine control module
(ECM).

Condition for Running the DTC

• The ignition switch is ON.
• The battery voltage is more than 16 volts.

Condition for Setting the DTC
Either of following condition is met:

• The ECM detects a malfunction in its internal main

central processing unit (CPU). (Flash Code 51)

• The ECM detects a malfunction in its internal sub

CPU. (Flash Code 52)

Action Taken When the DTC Sets

• The ECM illuminates the malfunction indicator

lamp (MIL) when the diagnostic runs and fails.

• The ECM limits accelerator control range.

Condition for Clearing the MIL / DTC

• The ECM turns OFF the MIL when the key is

cycled after a current DTC clears.

• A current DTC clears when the diagnostic runs and

does not fail.

• A history DTC clears after 20 consecutive driving

cycles without a fault. Or clear with the Tech 2 or
accelerator pedal operation.

DTC P0606 (Flash Code 51, 52)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or 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 Step 8

3

1.

Test each ground circuit between the engine
control module (ECM) (pins 1, 3, 4, 43, 62 and
81 of J-191 connector) and the chassis ground
terminal (J-9) for an open circuit or high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 4

4

1.

Turn OFF the ignition.

2.

Inspect for an intermittent, for poor tightening
and corrosion at the chassis ground terminal
(J-9).

3.

Repair the tightening or clean the corrosion as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 5

5

1.

Test each ECM main relay voltage feed circuit
between the ECM (pins 2 and 5 of J-191
connector) and the ECM main relay (pin 2 of
X-18 connector) for high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 6

 Engine Control System (4HK1)    6E-195

6

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM 1, 2, 3, 4, 5, 43, 62 and
81 of J-191 connector.

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7

7

Important:
Replacement ECM must be programmed.

Replace the ECM. Refer to Engine Control Module
(ECM) Replacement / Fuel Injector ID Code Data
Programming in this section.

Did you complete the replacement?

—

Go to Step 8

—

8

1.

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

2.

Clear the DTCs with he Tech 2.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 9

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-196    Engine Control System (4HK1) 

P0611 (Flash Code 34)

Circuit Description
The charge up circuit in the engine control module
(ECM) steps up the voltage for fuel injectors and is
divided into two banks, common 1 and 2. The common
1 covers fuel injectors in cylinders 1 and 4, and the
common 2 covers fuel injectors in cylinders 2 and 3. If
the common 1 fuel injector charge up voltage circuit in
the ECM is excessively low, this DTC will set.

Condition for Running the DTC

• The ignition switch is ON.
• The battery voltage is more than 18 volts.

Condition for Setting the DTC

• The ECM detects that the common 1 fuel injector

charge up circuit is insufficient charge.

Action Taken When the DTC Sets

• The ECM illuminates the malfunction indicator

lamp (MIL) when the diagnostic runs and fails.

• The ECM limits accelerator control range.
• The ECM inhibits pilot injection.

Condition for Clearing the MIL / DTC

• The ECM turns OFF the MIL when the key is

cycled after a current DTC clears.

• A current DTC clears when the diagnostic runs and

does not fail.

• A history DTC clears after 20 consecutive driving

cycles without a fault. Or clear with the Tech 2 or
accelerator pedal operation.

Diagnostic Aid

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

DTC P0611 (Flash Code 34)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or 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 Step 8

3

1.

Test each ground circuit between the engine
control module (ECM) (pins 1, 3, 4, 43, 62 and
81 of J-191 connector) and the chassis ground
terminal (J-9) for an open circuit or high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 4

4

1.

Turn OFF the ignition.

2.

Inspect for an intermittent, for poor tightening
and corrosion at the chassis ground terminal
(J-9).

3.

Repair the tightening or clean the corrosion as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 5

5

1.

Test each ECM main relay voltage feed circuit
between the ECM (pins 2 and 5 of J-191
connector) and the ECM main relay (pin 2 of
X-18 connector) for high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 6

 Engine Control System (4HK1)    6E-197

6

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM 1, 2, 3, 4, 5, 43, 62 and
81 of J-191 connector.

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7

7

Important:
Replacement ECM must be programmed.

Replace the ECM. Refer to Engine Control Module
(ECM) Replacement / Fuel Injector ID Code Data
Programming in this section.

Did you complete the replacement?

—

Go to Step 8

—

8

1.

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

2.

Clear the DTCs with he Tech 2.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 9

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