Opel Frontera UBS. Manual - part 2545

AUTOMATIC TRANSMISSION (AW30-40LE)

7A–43

DTC P0748 (FLASHING CODE 35) PRESSURE CONTROL SOLENOID FAILURE (STH)

DTCP0748

7A–44

AUTOMATIC TRANSMISSION (AW30-40LE)

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

D07RY00047

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

• Squat control inhibit

AUTOMATIC TRANSMISSION (AW30-40LE)

7A–45

• Changes solenoid output pattern as following figure
The shift theory at shift solenoid failure

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 circled numbers on
the diagnostic chart.

(1) With the key "ON", the voltage between the TCM

terminals (C78-4) and (C78-15 or 19) is 8 to 16V.

(2) When the driving wheels revolve with the 3rd speed

gear, the voltage is 1 V or less.

(3) The solenoid resistance is within the range of 11 to

15

Ω

.

Diagnostic aids:
In case of faulty connection, open or shorted circuit to
the TCM terminal (C78-4), 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.

Shift 

lever 

Position

Normal

S1 failure

S2 filure

S1 and S2 failure

Gear

S1

S2

Gear

S1

S2

Gear

S1

S2

Gear

S1

S2

D

1

❍

×

3

×→

❍

1

❍

O/D

2

❍

❍

❍

O/D

❍

→×

3

×

❍

❍

×

O/D

×

×

O/D

×

×

2

1

❍

×

3

×→

❍

1

❍

3

2

❍

❍

❍

O/D

❍

→×

3

×

❍

❍

×

L

1

❍

×

3

×→

❍

1

❍

3

2

❍

❍

❍

O/D

❍

→×

7A–46

AUTOMATIC TRANSMISSION (AW30-40LE)

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

DTCP0753