Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 630

7A1–20 AUTOMATIC TRANSMISSION (4L30-E)

GENERAL DIAGNOSIS PROCEDURE

END

Complaint

Follow 

PRELIMINARY

INSPECTION

CHART

Remove trans-
mission assembly
and repair/replace
as required

Reinstall
transmission
assembly

TEST DRIVING

Flush cooler lines

Perform repair

per

SYMPTOMS CHART

Replace

component

Can

fault

be corrected 

by on-car

component

replacement?

Problem

fixed?

NO

NO

YES

YES

AUTOMATIC TRANSMISSION (4L30-E) 7A1–21

PRELIMINARY INSPECTION CHART

Complaint

Check CHART3: TRANSMISSION AND
TCM IDENTIFICATION on page 7A1-64.

Check TRANSMISSION FLUID LEVEL
and CONDITION. See page 00-4.

Check manual linkage.

Verify engine performance.

Refer to Engine Section

Road test vehicle to verify concern.

See CHECK TRANS INDICATOR
CHART on page 7A1-25.

See ELECTRONIC DIAGNOSIS
Section of this manual on page 7A1-47.

See page 7A1-23 for TEST DRIVING

Refer to SELECTOR LEVER in this manual.
See page 7A1-145.

System 

OK

Note

codes

Does

symptom reflect

NORMAL

OPERATIONS

OF 4L30-E

TRANSMISSION?

(See page 7A1-15)

“CHECK TRANS”

flashing

Any 

Trouble Codes 

stored by

TCM?

Hydraulic

system appears 

OK!

Are any DTC’s 

stored in 

TCM?

YES

YES

YES

YES

NO

NO

NO

NO

TCM: Transmission Control Module

See MECHANICAL/HYDRAULIC
DIAGNOSIS Section on page 7A1-26.

7A1–22 AUTOMATIC TRANSMISSION (4L30-E)

CHECKING TRANSMISSION FLUID LEVEL
AND CONDITION

Refer to “SERVICING” of the SERVICE INFORMATION
(Section 00).

AUTOMATIC TRANSMISSION (4L30-E) 7A1–23

TEST DRIVING

Some 4L30-E automatic transmission complaints
vehicles will require a test drive as a part of the
diagnostic procedure. Some codes will not set
unless the vehicle is moving. The purpose of the
test drive is to duplicate the customer’s complaint
condition and set a current Transmission Control
Module (TCM) trouble code. Perform this procedure
before each 4L30-E automatic transmission repair,
and again after repairs are made.

IMPORTANT:

•

Duplicate the condition under which the
customer’s complaint was observed.

•

Depending on the complaint, line pressure
gauge and the scan tool may be required
during the test drive.

•

During the test drive, it is important to record
all necessary data from the areas being
monitored, for use in diagnosis. Also listen for
and note any unusual noises.

The following procedure should be used to test
drive 4L30-E automatic transmission complaint
vehicles:
1.

Turn the ignition ON without starting the
engine. Check that the “CHECK TRANS” lamp
comes on for approximately 2 to 3 seconds
and then goes out and remains out. 

•

If the lamp is flashing, GOTO CHECK TRANS
INDICATOR.

•

If no serial data is present, see Chart 1:
DIAGNOSTIC CONNECTOR AND VOLTAGE
SUPPLY TEST.

•

If the lamp stays ON or stays OFF, GOTO
“CHECK TRANS” CHECK.

2.

Drive the vehicle. During the test drive be sure
that the transmission achieves normal
operating temperature (approx. 20 minutes).
Allow the transmission to go through all of its
gear ranges, checking shift timing and
firmness. Duplicate the owner’s complaint
condition as closely as possible during the test
drive.

3.

If, during the test drive, the “CHECK TRANS”
lamp comes on, use the scan tool to check for
trouble codes.

4.

If, during the test drive, a problem is felt, but
the “CHECK TRANS” lamp does not come on
and no trouble codes are present, drive the
vehicle with the TCM disconnected (manually
shifting the vehicle).

•

In Manual L, the vehicle operates in first
gear.

•

In Manual 2, the vehicle operates in third
gear.

•

In Manual 3 or “D”, the vehicle operates in
fourth gear.

If the problem still exists with the TCM
disconnected, refer to the MECHANICAL/
HYDRAULIC DIAGNOSIS in this Section.

5.

If no problem has been found at this point,
check all underhood connections that supply
power to the TCM and ignition fuses.
Physically and visually inspect all the TCM
harness connectors for loose or corroded
terminals. Inspect the TCM ground points.