Isuzu N-Series. Manual - part 657

6E-50 Engine Control System (4HK1)

Breaker Box Connection Type B

Legend

1. Engine Control Module (ECM)
2. Adapter Harness
3. ECM – Harness Connector

4. Breaker Box
5. ECM connected

The ECM and other connectors have water proof
terminal that is not allowed to back probe. Breaker Box
Connection Type B is suitable usage to test short to
voltage circuit or signal check between the ECM and
electrical components.

CAUTION

To avoid electric shock;
Set the key switch to the "OFF" or "LOCK"
position before checking or repairing the
computer, wiring or/and connectors.

N6A6475E

Engine Control System (4HK1) 6E-51

Engine Control System Check Sheet

ENGINE CONTROL SYSTEM CHECK SHEET

Inspectors Name

Customer’s Name

Model & Model Year

Driver’s Name

Chassis No.

Date Vehicle Brought In

Engine No.

License No.

Odometer Reading

Km/miles

Engine Does
Not Run

Engine does not crank

No initial combustion

No complete combustion

Hard Start

Engine cranks slowly

Other (

)

Abnormal idling speed

High idling speed ( RPM)

Low idling speed ( RPM)

Rough idling

Incorrect Idle

Other (

)

Hesitation, sag, stumble

Surge, chuggles

Cut out, misses

Lack of power, sluggishness, sponginess

Poor
Driveability

Other (

)

Soon after starting

After accelerator pedal depressed

Engine Stall

During A/C operation

After accelerator pedal released

Shifting from N to D

Other (

)

Black smoke

White smoke

Poor fuel economy

Fuel knock, combustion noise

robl

Others

Other (

)

Dates problem occurred

Constant

Intermittently ( times per day/month)

Once only

Problem frequency

Other (

)

Fine

Cloudy

Rainy

Snow

Weather

Various/Other (

)

Hot (approx. )

Warm

Cool

Cold (approx. )

Outside
Temperature

Any temperature
Highway

Suburbs

City area

Uphill

Place

Downhill

Rough road

Other (

)

Over (approx.

tons)

No load

Load Condition

Other (approx.

tons)

Cold

Warming up

After warming up

Any temperature

Engine
Temperature

Other (

)

Starting

Just after starting (

Min.)

Idling

Racing

Driving

Constant speed

Acceleration

Deceleration

A/C switch On/Off

Engine Operation

Other (

)

Fuel Amount

Full

Above 1/2

Below 1/2

Near empty

Condi

on When

robl

Fuel Bland

Condition of MIL

Remains On

Intermittently turns On

Does not turn On

Present Code

Nothing

P or U Code
No. (

)

Diagnostic Trouble
Code (DTC) or Flash
Code

History Code

Nothing

P or U Code
Code No. (

)

Other Additional
Condition

N6A6476E

6E-52 Engine Control System (4HK1)

Diagnostic Starting Point – Engine
Controls

Begin the system diagnosis with Diagnostic System
Check – Engine Controls. The Diagnostic System
Check – Engine Controls will provide the following
information:

• The identification of the control modules which

command the system.

• The ability of the control modules to communicate

through the serial data circuit.

• The identification of any stored diagnostic trouble

codes (DTCs) and the their statuses.

The use of the Diagnostic System Check – Engine
Controls will identify the correct procedure for
diagnosing the system and where the procedure is
located.

Important:
Engine Control System Check Sheet must be used to
verify the customer complaint, you need to know the
correct (normal) operating behavior of the system and
verify that the customer complaint is a valid failure of
the system.

Diagnostic System Check – Engine
Controls

Description
The Diagnostic System Check – Engine Controls is an
organized approach to identifying a condition that is
created by a malfunction in the electronic engine
control system. The Diagnostic System Check must be
the starting point for any driveability concern. The
Diagnostic System Check directs the service technician
to the next logical step in order to diagnose the
concern. Understanding and correctly using the
diagnostic table reduces diagnostic time, and prevents
the replacement of good parts.

Test Description
The numbers below refer to the step numbers on the
diagnostic table.
1. Lack of communication may be because of a partial
or a total malfunction of the Keyword 2000 serial data
circuit. The specified procedure determines the
particular condition.
4. The presence of DTCs which begin with U, indicate
that some other module is not communicating.
10. If there are other modules with DTCs set, refer to
the DTC list. The DTC list directs you to the appropriate
diagnostic procedure. If the control module stores
multiple DTCs, diagnose the DTCs in the following
order.

• Component level DTCs, such as sensor DTCs,

solenoid DTCs, actuator DTCs, and relay DTCs.
Diagnose the multiple DTCs within this category in
numerical order. Begin with the lowest numbered
DTC, unless the diagnostic table directs you
otherwise.

Diagnostic System Check – Engine Controls
Important:

• DO NOT perform this diagnostic if there is not a

driveability concern, unless another procedure
directs you to this diagnostic.

• Before you proceed with diagnosis, search for

applicable service bulletins.

• Unless a diagnostic procedure instructs you, DO

NOT clear the DTCs.

• If there is a condition with the starting system, refer

to the starting system section in the engine
mechanical.

• Ensure the battery has a full charge.
• Ensure the battery cables (+) (

−) are clean and

tight.

• Ensure the ECM grounds are clean, tight, and in

the correct location.

• Ensure the ECM harness connectors are clean

and correctly connected.

• Ensure the ECM terminals are clean and correctly

mating.

• Ensure the vehicle maintenance has been done

enough.

• Ensure the Fuel Injector ID Code Data is correctly

programmed.

• If there are fuel system DTC’s (P0087, P0088,

P0089, P1093, P1094 or P1095), diagnose sensor
DTCs, solenoid DTCs, actuator DTCs and relay
DTCs FIRST.

Engine Control System (4HK1) 6E-53

Step

Action

Value(s)

Yes

Install the Tech 2.

Turn ON the ignition, with the engine OFF.

Attempt to establish communication with the
listed control modules.

• Engine control module (ECM)
• Transmission control module (TCM)

(Smoother only)

• Hill start aid (HSA) control module (If so

equipped)

• Supplemental restraint system (SRS)

control module (If so equipped)

Does the Tech 2 communicate with all the listed
control modules?

—

Go to Step 2

Go to Tech 2 Does

Not Communicate

with Keyword

Device

Attempt to start the engine.

Does the engine start and idle?

—

Go to Step 3

Go to Engine

Cranks but Does

Not Run

Select the DTC display function for the following
control modules:

• ECM
• TCM (Smoother only)
• HSA control module (If so equipped)
• SRS control module (If so equipped)

Does the Tech 2 display any DTCs?

—

Go to Step 4

Go to Step 11

Does the Tech 2 display DTCs which begin with a U
or other control module communication fault
DTCs?

—

Go to Applicable

DTC

Go to Step 5

Does the Tech 2 display ECM DTCs P0601, P0603,
P0606, P0611, P0612 or P1630?

—

Go to Applicable

DTC

Go to Step 6

Does the Tech 2 display ECM DTC P1625?

—

Go to Applicable

DTC

Go to Step 7

Does the Tech 2 display ECM DTCs P1631, P1632,
P1633, P1634 or P1635?

—

Go to Applicable

DTC

Go to Step 8

Does the Tech 2 display ECM DTCs P0219, P0335,
P0336, P0340, P0341 or P1345?

—

Go to Applicable

DTC

Go to Step 9

Does the Tech 2 display ECM DTCs P0090, P0201,
P0202, P0203, P0204, P1261 or P1262?

—

Go to Applicable

DTC

Go to Step 10

Is there any other code in any controller that has
not been diagnosed?

—

Go to Applicable

DTC

Go to Step 11

Is the customer’s concern with the transmission?

—

Go to Diagnostic

System Check –

Transmission

Controls

Go to Step 12

Is the customer’s concern with the HSA system?

—

Go to Diagnostic

System Check –

HSA Controls

Go to Step 13

Is the customer’s concern with the SRS airbag
system?

—

Go to Diagnostic

System Check –

SRS Controls

Go to Step 14

Content .. 655 656 657 658 ..