Isuzu Trooper (1998-2002 year). Manual - part 791

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–73

Test Description

The numbers below refer to the step numbers on the
diagnostic chart:

2. This test checks the function of the range switch

(mode switch).

3. This test checks for selected gear ratio vs. a ratio

not obtainable under normal driving conditions.

DTC P0756 Shift Solenoid B Performance (Stuck OFF) 

Step

Action

Yes

No

1

Were you sent here from the “Powertrain On–Board Diagnostic
(OBD) System Check”?

Go to Step 2

Go to OBD

System Check

Refer to

Driveability and

Emissions in

Engine section

2

1. Install the scan tool.
2. With the engine “off”, turn the ignition switch “on”.

NOTE: Before clearing DTC(s), use the scan tool to record “Freeze
Frame” and “Failure Records” for reference, as data will be lost
when the “Clear Info” function is used.

3. Record the DTC “Freeze Frame” and “Failure Records”.
4. With the engine operating, apply the brake pedal and select

each transmission range DL, D2, D3, D4, N, R, and P.

Does each selected transmission range match the “TR Switch” on
the scan tool?

Go to Step 3

Go to “Range

Switch Logic

Table”

3

1. While the engine is operating, raise the drive wheels.
2. With the transmission in D4 range, use the scan tool to

command 1st, 2nd, and 3rd, and 4th gears while accelerating
the vehicle.

Was a 4–3–3–4 shift pattern detected? (Road testing the vehicle
may be necessary.)

Go to Step 4

Go to Diagnostic

Aids

4

Check the shift solenoid/hydraulic circuit for:

D

One or both of the shift solenoids for an internal malfunction.

D

Contamination or sediment in one or both of the shift
solenoids.

D

Damaged seals on the one or both of the shift solenoids.

Refer to Solenoid (Main Case Valve Body) in Automatic
Transmission (4L30–E) section.

Was a problem found and corrected?

Go to Step 5

Go to Diagnostic

Aids

5

1. After the repair is complete, use the scan tool to select “DTC”,

then “Clear Info” function and road test the vehicle.

2. Review the scan tool “DTC Info”.

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

Begin diagnosis

again

Go to Step 1

Repair verified
Exit DTC table

7A1–74 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P0757 Shift Solenoid B Performance (Stuck ON)

D07RT011

Circuit Description

The shift solenoid B is used to control fluid flow acting on
the 2–3 shift valves.  The solenoid is a normally open
exhaust valve that is used with the shift solenoid A to allow
four different shift combinations.
This DTC detects when there is only a 1–2–2–1 shift
pattern depending on the state of the mechanical failure
instead of a 1–2–3–4 shift pattern. This is a type “B” DTC.

Conditions For Setting The DTC

D

No ETC DTCs.

D

No OSS DTCs P0722 or P0723.

D

No TCC solenoid DTC P0742, P1860, P1870.

D

No shift solenoid A DTC P0753.

D

No shift solenoid B DTC P0758.

D

Gear range is D4.

D

Output speed is greater than 375 rpm.

D

Transmission fluid temperature is between 20

°

 and

130

°

C (68

°

 and 266

°

F).

D

No range code P0705, P0706.

D

No torque code (to be confirmed).

D

Engine run for more 0 seconds and not influed cut-off
(to  be confirmed).

All the above conditions have been met and the
combination of condition 1,2 occur two consecutive
times.

Condition 1:

D

3rd gear is commanded for 

≥

 1 sec

D

40 

≤

 Engine Torque 

≤

 400 N·m

D

Throttle positon 

≥

 10%

D

–8000 

≤

 TCC slip 

≤

 8000 rpm

D

Transmission out speed 

≥

 375 rpm

D

Speed ratio 

≥

 0.6

D

1.44 

≤

 Modeled Ratio 

≤

 2.4 for 4 seconds

Condition 2:

D

4th Gear is commanded for 

≥

 1 sec.

D

15 

≤

 Engine Torque 

≤

 400 N·m

D

Trottle position 

≥

 10%

D

–8000 

≤

 TCC slip 

≤

 8000 rpm

D

Speed ratio 

≥

 0.6

D

2.75 

≤

 Modeled Ratio 

≤

 3.2 for 2 seconds

Action Taken When the DTC Sets

D

Maximum line pressure.

D

For lamp illuminate refer to DTC type definition (type
B).

D

Turn force motor OFF.

Conditions For Clearing The MIL/DTC

D

The PCM will turn off the MIL and CHECK TRANS
Lamp after three consecutive ignition cycles without a
failure reported.

D

The DTC can be cleared from the PCM history by
using a scan tool.  

D

The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.

D

The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.

Diagnostic Aids

D

Verify that the transmission meets the specifications
in the 4L30-E shift speed chart.

D

Other internal transmission failures may cause more
than one shift to occur.

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–75

Test Description

The numbers below refer to the step numbers on the
diagnostic chart:

2. This test checks the function of the range switch

(mode switch).

3. This test checks for selected gear ratio vs. a ratio

not obtainable under normal driving conditions.

DTC P0757 Shift Solenoid B Performance (Stuck ON) 

Step

Action

Yes

No

1

Were you sent here from the “Powertrain On–Board Diagnostic
(OBD) System Check”?

Go to Step 2

Go to OBD

System Check

Refer to

Driveability and

Emissions in

Engine section

2

1. Install the scan tool.
2. With the engine “off”, turn the ignition switch “on”.

NOTE: Before clearing DTC(s), use the scan tool to record “Freeze
Frame” and “Failure Records” for reference, as data will be lost
when the “Clear Info” function is used.

3. Record the DTC “Freeze Frame” and “Failure Records”.
4. With the engine operating, apply the brake pedal and select

each transmission range DL, D2, D3, D4, N, R, and P.

Does each selected transmission range match the “TR Switch” on
the scan tool?

Go to Step 3

Go to “Range

Switch Logic

Table”

3

1. While the engine is operating, raise the drive wheels.
2. With the transmission in D4 range, use the scan tool to

command 1st, 2nd, and 3rd, and 4th gears while accelerating
the vehicle.

Was a 4–3–3–4 shift pattern detected? (Road testing the vehicle
may be necessary.)

Go to Step 4

Go to Diagnostic

Aids

4

Check the shift solenoid/hydraulic circuit for:

D

One or both of the shift solenoids for an internal malfunction.

D

Contamination or sediment in one or both of the shift
solenoids.

D

Damaged seals on the one or both of the shift solenoids.

Refer to Solenoid (Main Case Valve Body) in Automatic
Transmission (4L30–E) section.

Was a problem found and corrected?

Go to Step 5

Go to Diagnostic

Aids

5

1. After the repair is complete, use the scan tool to select “DTC”,

then “Clear Info” function and road test the vehicle.

2. Review the scan tool “DTC Info”.

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

Begin diagnosis

again

Go to Step 1

Repair verified
Exit DTC table

7A1–76 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P0758 Shift Solenoid B Electrical

LHD

D07R200053