Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 659

7A1–136 AUTOMATIC TRANSMISSION (4L30-E)

INTERMITTENT CONDITIONS

If the TECH2 displays a diagnostic trouble code as
intermittent, or if after a test drive a DTC does not
reappear though the detection conditions for this
DTC are present: the problem is most likely a faulty
electrical connection or loose wiring. Terminals and
grounds should always be the prime suspect.
Intermittents rarely occur inside sophisticated
electronic components such as the TCM.

Use the DTC information to understand which wires
and sensors are involved.

When an intermittent problem is encountered,
check suspect circuits for:
(1)

Poor terminal to wire connection.

(2)

Terminals not fully seated in the connector
body (backed out).

(3)

Improperly formed or damaged terminals.

(4)

Loose, dirty, or corroded ground connections:

HINT: Any time you have an intermittent in
more than one circuit, check whether the circuits
share a common ground connection.

(5)

Pinched or damaged wires.

(6)

Electro-Magnetic Interference (EMI):

HINT: Check that all wires are properly routed
away from spark plug wires, distributor wires,
coil, and generator. Also check for improperly
installed electrical options, such as lights, 2-way
radios, etc.

Use the F3: SNAPSHOT mode of the TECH2 to help
isolate the cause of an intermittent fault. The
snapshot mode will record information before and
after the problem occurs. Set the snapshot to
“trigger” on the suspect DTC or, if you notice the
reported symptom during test drive, trigger the
snapshot manually.
(1)

NOTE: When TECH2 is plugged the shifts are
always done at the maximum pressure. This
means that if you do SNAPSHOT while driving
you will notice firm shifts.

After the snapshot has been triggered, command
the TECH2 to play back the flow of data recorded
from each of the various sensors. Signs of an
intermittent fault in a sensor circuit are sudden
unexplainable jump in data values out of the
normal range.

CASE: problem still not solved GOTO TCM MEM-
CAL REPLACEMENT.

AUTOMATIC TRANSMISSION (4L30-E) 7A1–137

TCM MEM-CAL REPLACEMENT

(TCM: Transmission Control Module)

1.

MEM-CAL (Memory and Calibration Unit)
Information for specific transmission and vehicle is
programmed using an integrated circuit called a
MEM-CAL.
This allows one model of controller to be used for
many different vehicles.
The MEM-CAL is located inside the TCM and has
information on the transmission, shift map, etc.
several others.

2.

MEM-CAL Replacement
If the diagnostic procedures require MEM-CAL
replacement, the MEM-CAL should be replaced using
the following procedures.

NOTE:
The ignition must be “OFF”, when disconnecting or
reconnecting the TCM connector, to prevent internal
damage to the TCM.

NOTE:
To prevent possible Electrostatic Discharge damage
to the TCM, do not touch the connector pins or
soldered components on the circuit board.

MEM-CAL Replacement Procedure:

1. Remove TCM from passenger compartment:

(1) Disconnect negative (–) battery cable.
(2) Remove connectors from TCM.
(3) Remove TCM from passenger compartment.
(4) Remove MEM-CAL access cover.

NOTE:
Do not remove any of the other screws.

TCM

MEM-CAL

Access

cover

('96&'97)

2. Remove MEM-CAL from TCM.

•

Using two fingers, pinch both retaining clips
and remove MEM-CAL from the MEM-CAL
socket.
Using unapproved MEM-CAL removal
methods may cause damage to the MEM-CAL
or socket.

826RV010

7A1–138 AUTOMATIC TRANSMISSION (4L30-E)

3. Check new MEM-CAL

•

Check the part number of the new MEM-CAL
to make sure it is the correct replacement part.

4. Install new MEM-CAL

(1) Small notches in the MEM-CAL must be

aligned with small notches in the MEM-CAL
socket.

(2) Gently press down on the ends of the MEM-

CAL until the clips are locked. Listen for the
click.

5. Install TCM to passenger compartment:

(1) Install MEM-CAL access cover.
(2) Install TCM to passenger compartment.
(3) Connect TCM connectors.
(4) Connect negative (–) battery cable.
(5) Do an IGNITION CYCLE and verify correct

CHECK TRANS indicator operation.

MEM-CAL

MEM-CAL SOCKET

PRESS DOWN

AUTOMATIC TRANSMISSION (4L30-E) 7A1–139

MEMO