Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 650

7A1–100 AUTOMATIC TRANSMISSION (4L30-E)

DIAGNOSTIC TROUBLE CODE (DTC) 37

TORQUE MANAGEMENT SERIAL LINE FAULTY

This DTC flashes the CHECK TRANS indicator and
sets the BACKUP MODE.

Circuit Description:

•

Torque Management is a function that decreases
the engine torque during transmission shifts. To
do so the Transmission Control Module (TCM)
exchanges information on a wire with the Engine
Control Module (ECM) that governs the Engine.
This wire is the Data Link Connector which is also
used by the Scan tool to communicate with the
TCM and the ECM.

Diagnostic Aids:

•

This Diagnostic is not an electrical test done by
the TCM but a test between different information
(“logic test”).

•

Detection conditions:
1 Torque control failure detected
2 Each time a shift occurs with the Torque

Management active, the TCM sends a
message to the ECM. If the ECM does not
acknowledge this message, the DTC is stored.

•

Action after the detection time: BACKUP MODE

•

Recovery conditions: To recover, do an IGNITION
CYCLE.

NOTE:
1

When connecting the TECH2 to the data link
connector, be sure to turn off the ignition
switch.

Since the torque management exchanges
information between the TCM and the ECM at
all times, the DTC37 is sometimes detects in
the following condition.
However, this is not an abnormal condition.

•

When the engine stops while driving and
then it is restarted.

•

When the battery voltage goes down
excessively and the engine does not start
again.

When DTC37 is detected in the above
conditions, turn off the ignition switch, correct
the abnormal condition and erase the trouble
code.

SERIAL DATA

TRANSMISSION
CONTROL
MODULE (TCM)

ENGINE
CONTROL
MODULE
(ECM)

C-95

C8(8)

E-61

YEL

C-102

DATA LINK
CONNECTOR

BLK

YEL/BLK

GRN

FUSE (EB-12)

D16(32)

DIAGNOSIS
INPUT

C-102

D07LW017

AUTOMATIC TRANSMISSION (4L30-E) 7A1–101

YES

DIAGNOSTIC TROUBLE CODE (DTC) 37

TORQUE MANAGEMENT SERIAL LINE FAULTY

•

Peform TECH2 SELF-TEST GOTHROUGH TECH2
CONNECTION.

IF: TECH2 OK:

•

Ignition switch OFF.

•

Disconnect TECH2.

•

Connect ohmmeter between connector C-102 terminal
4 or 5 and ground.

IF: Display approx. 0 ohms :

•

Ignition switch ON.

•

Connect voltmeter between connector C-102 terminal
16 and 4 or 5.

IF: Display battery voltage:

•

Ignition switch OFF.

•

Connect ohmmeter between connector C-102 terminal
9 and ECM connector E-61 terminal 35.

•

Then connect ohmmeter between TCM connector C-95
terminal C8 and ECM connector E-61 terminal 35.

IF: Display approx. 0 ohms:

•

Check for short between connector C-102 terminal 9
and ground and between connector C-102 terminal 9
and B+.

IF OK, GOTO TCM MEM-CAL REPLACEMENT.

See TECH2 OPERATOR’S MANUAL.

Check wire for open.

Check Engine Control Module (ECM)
and wire to ECM and wire to battery
and data link connector C-102.

Check wire for open.

7A1–102 AUTOMATIC TRANSMISSION (4L30-E)

DIAGNOSTIC TROUBLE CODE (DTC) 41

SOLENOID A SHORT TO PLUS

This DTC flashes the CHECK TRANS indicator and
sets the BACKUP MODE.

Circuit Description:

•

The solenoid A is a simple ON/OFF solenoid
located in the main case valve body. The
solenoid is the normally closed-type. In second or
third gear the Transmission Control Module
(TCM) energizes the solenoid to open a fluid inlet
port. When the port is open, fluid pressure
actuates the shift valve.

•

The solenoid is activated by a current. This
current is produced by applying a voltage to one
side (the High side) and a ground to the other
side (Low side).

•

The High Side Driver (HSD) is a circuit of the TCM
that acts as a switch between the solenoids and
the supply voltage. The High side of the solenoid
is permanently supplied with voltage, except in
BACKUP MODE or when ignition is OFF the HSD
is turned OFF.

•

The TCM continually monitors the solenoid
connection to its Low Side Driver (LSD) for either
low or high voltage. The LSD is a circuit of the
TCM that acts as a switch between the solenoid
and ground. When the solenoid is commanded
ON the TCM is switching the solenoid to ground.

•

There are two tests of the LSD: when the engine
is cranked (DTC82) and when the ignition is
turned ON (DTC41).

•

When the ignition is turned ON, and before the
engine is cranked, the TCM activates the shift
solenoids (A, B and Band) to check for short
circuits or open circuits. To do so the gear is set
to 4th, 3rd, 1st, 1st with band apply, 4th with no
HSD. Each one of the 5 tests requires 0.15
second. If the engine is cranked before the end of
all tests, the remaining tests are not done.

Diagnostic Aids:

•

This diagnostic is an electrical test done by the
TCM.

•

Detection conditions:
1 The solenoid Low side connected to TCM

terminal A2 is shorted to plus.

2 The test is only done when ignition is ON.
3 Engine Speed < 480 RPM (not cranked) and

Output Speed = 0 RPM.

4 The condition needs to be present for 0.15 to

0.88 second after ignition switch ON.

•

Action after the detection time: BACKUP MODE.

•

Recovery conditions: To recover, do an IGNITION
CYCLE.

TRANSMISSION
CONTROL
MODULE (TCM)

SHIFT
SOLENOID
A

SHIFT
SOLENOID
B

BAND
APPLY
SOLENOID

AUTOMATIC
TRANSMISSION

M-7

3(D)

4(C)

BRN/WHT

YEL/GRN

1(A)

BRN/BLK

H-23

YEL/BLK

2(B)

M-7

C12(12)

A2(2)

A3(3)

A9(9)

SHIFT &
BAND APPLY
SOLENOID
CONTROL

C-95

RED/BLU

GRN

A7(7)

A4(4)

BATTERY

ECM MAIN RELAY

BATTERY
INPUT

IGNITION
INPUT

C-96

GROUND

BRN/WHT

BRN/BLK

D07LW018

AUTOMATIC TRANSMISSION (4L30-E) 7A1–103

DIAGNOSTIC TROUBLE CODE (DTC) 41

SOLENOID A SHORT TO PLUS

•

Ignition switch OFF.

•

Disconnect Transmission Control Module (TCM)
connectors C-95 and C-96.

•

Connect ohmmeter between connector C-96
terminals A2 and A7 (TCM ignition) then between A2
and A4 (TCM battery) then between A2 and C12.

IF: Short circuit:

YES

•

Check for faulty connector or wiring between
terminal A2 and the shorted terminal.

•

Repair.

The problem is intermittent.
GOTO INTERMITTENT
CONDITIONS.

Repair.

YES

•

Connect ohmmeter between A2 and A3 then between
A2 and A9.

IF: Short circuit:

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