Isuzu N-Series. Manual - part 896

Transmission Control System (Smoother) 7A-39

Torque Learned Duty Ratio
This parameter displays the learned gearshift clutch
solenoid valve control duty ratio when the half-clutch
position is learned.
Half-Clutch Adjustment Duty Ratio
This parameter displays the adjustment value of the
gearshift clutch solenoid valve control duty ratio when
the gearshift clutch is engaged. The half-clutch
adjustment switch is used to adjust the clutch
engagement timing. 
Engine Type
This parameter displays the programmed engine type.
Engine Type Learning Status
This parameter displays the learning state of the engine
type. Not Learned indicates initialed state that is
replaced to a new TCM. Learned indicates learning
process is completed state.
Transmission Type
This parameter displays the programmed engine type.
Transmission Type Learning Status
This parameter displays the learning state of the
transmission type. Not Learned indicates initialed state
that is replaced to a new TCM. Learned indicates
learning process is completed state.
Speedometer Driven Gear Teeth
This parameter displays the programmed speedometer
driven gear teeth.
Speedometer Driven Gear Learning Status
This parameter displays the learning state of the
speedometer driven gear teeth. Not Learned indicates
initialed state that is replaced to a new TCM. Learned
indicates learning process is completed state.
Gear Position Learning Status
This parameter displays the learning state of the half-
clutch position. Not Learned indicates initialed state that
is replaced to a new TCM. Learned indicates learning
process is completed state.
Torque Learning Status
This parameter displays the learning state of the
transmission gear select and shift position. Not Learned
indicates initialed state that is replaced to a new TCM.
Learned indicates learning process is completed state.

7A-40 Transmission Control System (Smoother)

Transmission Contol System Check Sheet

Check list for Smoother control system

Specific example

Inspector's name

Customer's name

Driver's name

Date vehicle brought in

Registration No.

Model type and model year

Trouble symptom

Engine does
not start

Engine does not crank

At gear-in

At neutral

When emergency switch is ON

Idle speed is incorrect

Abnormal idling

High (         rpm)

Low (         rpm)

Others

Others

Others

Others

Others

Others

Various/
others

Others

Others

Others

Drivability is low

Engagement/disengagement is felt at shift-up

Body vibration

Engine vibration

Noise

Large shock at gearshift

Large shock at starting to move

Running
not possible

Immediately after starting to move

When accelerator pedal is released

When A/C is operated

Immediately after replacing engine oil

Immediately after replacing
transmission oil

When gear is shifted up

Gearshift

Gear is not shifted

Gear is shifted

Noise

Gear clash

Accelerator
pedal

Blow up

Slow response

Rough

Engine stall

Brake lamp does not come on

Trouble occurrence data

Frequency of trouble

Always

Sometimes (How many times:        per date/month)

Once

Trouble condition

Weather

Fine

Cloudy

Rain

Snow

Ambient temperature

30     or more

Around 20   30

Around 10   15

0     

or less (       )

Location

Expressway

Suburb

Urban area

Uphill

Downhill

Rough road

Engine/
transmission temperature

Cold

Warming-up

After warmed-up

Operating condition

When starting

Immediately after starting (     minutes)

Idling

Racing

During operation

At a constant speed

At acceleration

At deceleration

A/C SW, other SW  ON/OFF

Smoother warning lamp

ON

Sometimes comes on

Not come on

Not sure

Not sure

Not sure

Present

* When was the transmission oil replaced last time?

Were genuine transmission oil, filter, etc. used?

When was the engine oil replaced last time?

Buzzer

Beeped

Not beep

Lamp indication fault

Economy mode

Indicator display

1st gear start

Past trouble history

(Year       Month/Date      )
(Year       Month/Date      )

About learning

Torque learning

Torque learning value

Gear learning

Adjustment learning value

Trouble occurrence data

Phase

Shift mode

Target gear

Buzzer mode

When gear is engaged 

while vehicle is 

stopped, engine stalls

Engine coolant temperature

Vehicle No.
Transmission type
Transmission No.
Engine model
Odometer reading

N7A2073E

Transmission Control System (Smoother) 7A-41

Diagnostic Starting Point - Transmission Controls

Begin the system diagnosis with Diagnostic System
Check Transmission Controls. The Diagnostic System
Check Transmission 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 - Transmission
Controls will identify the correct procedure for
diagnosing the system and where the procedure is
located.

Important:
Transmission 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 - Transmission
Controls 

Description
The Diagnostic System Check Transmission Controls is
an organized approach to identifying a condition that is
created by a malfunction in the electronic transmission
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. 

5. The presence of DTCs which begin with U, indicate
that some other module is not communicating. 
11.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.

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.

• Ensure the battery has a full charge.

• Ensure the battery cables (+) (

−) are clean and

tight.

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

the correct location.

• Ensure the TCM harness connectors are clean and

correctly connected.

• Ensure the TCM terminals are clean and correctly

mating.

• Ensure the vehicle maintenance has been done

enough.

• Ensure the vehicle information data is correctly

programmed and transmission gear select & shift
position and half-clutch position is correctly
learned.

• If there are DTC’s P0718, P0726, P0909, P0915 or

P0919, diagnose sensor DTCs, solenoid DTCs,
actuator DTCs and relay DTCs FIRST.

Step

Action

Value(s)

Yes

No

1

1. Install the Tech 2.
2. Turn ON the ignition, with the engine OFF. 
3. Attempt to establish communication with the

listed control modules.

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

7A-42 Transmission Control System (Smoother)

2

1. Turn OFF the ignition for 30 seconds.
2. Turn OFF the emergency switch.
3. Turn ON the ignition, with the engine OFF.

Does the transmission warning lamp illuminate?

—

Go to Step 3

Go to Transmission 

Warning Lamp 

Inoperative 

3

Attempt to crank the engine.

Does the engine crank?

—

Go to Step 4

Go to Engine Does 

Not Crank

4

Attempt to start the engine.

Does the engine start and idle?

—

Go to Step 5

Go to Engine Cranks 

But Does Not Run in 

Engine Control 

Section

5

Select the DTC display function for the following
control modules:
• ECM
• TCM 
• SRS control module (If so equipped)

Does the Tech 2 display any DTCs?

—

Go to Step 6

Go to Step 13

6

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 7

7

Does the Tech 2 display TCM DTCs P0602, P0605
or P0613?

—

Go to Applicable 

DTC

Go to Step 8

8

Does the Tech 2 display TCM DTCs P0885 or
P0889?

—

Go to Applicable 

DTC

Go to Step 9

9

Does the Tech 2 display TCM DTCs P0715, P0717,
P0721, P0904 or P0914?

—

Go to Applicable 

DTC

Go to Step 10

10

Does the Tech 2 display TCM DTCs P0740, P0742,
P0902 or P0903?

—

Go to Applicable 

DTC

Go to Step 11

11

Does the Tech 2 display TCM DTCs P0851, P0852,
P0906 or P0907?

—

Go to Applicable 

DTC

Go to Step 12

12

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

—

Go to Applicable 

DTC

Go to Step 13

13

Is the customer’s concern with the engine?

—

Go to Diagnostic 

System Check - 

Engine Control

Go to Step 14

14

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

—

Go to Diagnostic 

System Check SRS 

Control

Go to Step 15

15

Drive vehicle and verify if any engine or
transmission related driveability concern exist.
Perform Gearshift Control System Check as
necessary. Refer to Gearshift Control System
Check in this section.

Does an engine or transmission driveability concern
exist?

—

Go to Symptoms - 

Engine Controls in 

Engine Control 

Section or Diagnosis 

based on vehicle 

condition for 

Transmission

System OK

Step

Action

Value(s)

Yes

No