Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 304

AUTOMATIC TRANSMISSION (AW30-40LE) 7A-65

DTC P0748 (FLASHING CODE 35)

PRESSURE CONTROL SOLENOID FAILURE (STH)

Step Action

Value(s)

Yes

No

1

1. Turn the ignition "OFF".
2. Disconnect the TCM 20 pin connector.
3. Connect an ohmmeter between the TCM 20

pin connector terminal (11) and (8).

Is the resistance within the specified value?

5-5.6

Ω (at 20°C)

Go to Step 2

Go to Step 3

2

1. Connect an ohmmeter between the TCM 20

pin connector terminal (11) and ground
terminal (15 or 19).

2. Then, connect between the TCM 20 pin

connector terminal (11) and ignition terminal
(20).

3. Then, connect TCM 20 pin connector

terminal (8) and ground terminal (15 or 19),
then between TCM 20 pin connector
terminal (8) and ignition terminal (20).

Does display a short circuit?



Go to Step 4

The problem is

intermittent.

Refer to

"Diagnostic

aids".

3

1. Disconnect the A/T 8 pin connector.
2. Connect an ohmmeter between the A/T 8 pin

connector terminal (2) and (6).

Is the resistance within the specified value?

5-5.6

Ω (at 20°C)

Go to Step 5

Go to Step 6

4

Repair the short circuit.
Is the repair complete?



Go to Step 7



5

Repair the wiring harness for open between TCM
20 pin connector and A/T 8 pin connector.
Is the repair complete?



Go to Step 7



6

1. Check the wiring harness for open between

A/T 8 pin connector and pressure control
solenoid.

2. If OK, replace pressure control solenoid

(valve body assembly).



Go to Step 7



7

1. After the repair is complete, use the scan tool

to select "DTC", then "Clear Info" function

2. Make a road running test for the vehicle.
3. Review the scan tool "DTC Info".

Has the last test failed or is the current DTC
displayed?



Begin the
diagnosis

again.

Go to Step 1

System OK

7A-66 AUTOMATIC TRANSMISSION (AW30-40LE)

DTC P0753 (FLASHING CODE 31) SOLENOID 1 FAILURE (S1)

UBS (For General Export)

D07R200062

TFR/S (For Australia) and TFR (For South Africa)

D07L200007

AUTOMATIC TRANSMISSION (AW30-40LE) 7A-67

‘01TFR (For Thailand)

D07L100010

Circuit description:

The shift solenoid S1 changes the hydraulic route with
the signals from the TCM according to the vehicle
speed and the throttle opening to control shifting. When
the solenoid S1 or S2 fails, the hydraulic circuit is
mechanically operated as a backup.

Fail-safe control:

The TCM controls fail-safe by detecting S1, S2 shift
solenoid failure.

Failure detection:

GND SHORT detection

• When SHORT detection continues for 0.3 sec.

• When SHORT failure detection continues 8 times.

Open detection

• When OPEN detection continues for 0.5 sec.

• When OPEN failure detection continues 8 times.

Contents of control:

At failure detection

• Lock-up control inhibit

• Up hill and down hill control inhibit (For UBS)

• Squat control inhibit

7A-68 AUTOMATIC TRANSMISSION (AW30-40LE)

• Changes solenoid output pattern as following figure

The shift theory at shift solenoid failure

Normal

S1 failure

S2 filure

S1 and S2 failure

Shift

lever

Position

Gear S1 S2 Gear S1 S2 Gear

S1 S2 Gear S1 S2

1

××××

1

2

3

××××

3

××××

D

O/D

××××

××××

O/D

××××

O/D

××××

O/D

1

××××

1

2

2

3

××××

3

O/D

××××

3

1

××××

1

L

2

3

O/D

3

At failure decision

Executes following items in addition to above control
items at failure detection.

• Turns Solenoid power supply OFF

• Blinks "CHECK TRANS" lamp

• Stores the failure information in failure-memory

*Prohibits failure detection of S1, S2, SL, STH,

Selector position switch, and Oil temp. sensor.

Conditions of turning "CHECK TRANS" off:
Turns "CHECK TRANS" lamp off after ignition is turned
ON

→ OFF→ ON.

Reversion conditions from fail-safe:

At failure detection
When a normal judgment is obtained by rechecking

during shifting.

At failure decision
Recovers at the same time as the conditions of

turning “CHECK TRANS” lamp off are satisfied.

Test description:

The following numbers correspond to the step numbers
on the diagnostic chart.
1. With the key "ON", the voltage between the TCM

20 pin connector terminals (4) and (15 or 19) is 8 to
16V.

4. When the driving wheels revolve with the 3rd speed

gear, the voltage is 1 V or less.

3.6.8.11. The solenoid resistance is within the range of

11 to 15

Ω (at 20°C).

Diagnostic aids:

In case of faulty connection, open or shorted circuit to
the TCM 20 pin connector terminal (4), DTC P0753 is
displayed. A intermittent failure may be caused by a
poor connection, rubbed through wire insulation or a
wire broke inside the insulation.