Isuzu Trooper (2000 year). Service manual - part 414

7A1–70 TRANSMISSION CONTROL SYSTEM (4L30–E)

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 D1, 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 1st gear commanded and not achieved, or 4th gear
commanded and other than 4th gear occurred? (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

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–71

DTC P0758 Shift Solenoid B Electrical

D07RY00014

Circuit Description

D

The shift solenoid B is a simple on/off solenoid
located in the main case valve body.  It is normally
open.  When the port is open, fluid pressure actuates
the shift valve.  In first or second gear, the Powertrain
Control Module (PCM) energizes the solenoid to
close a fluid inlet port.

D

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

D

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

This DTC detects a continuous open or short to ground in
the shift solenoid B circuit or shift solenoid B.  This is a
type “B” DTC.

Conditions For Setting The DTC

D

Ignition is “on”, Engine “run”.

D

Battery voltage is between 10 and 16 volts.

D

The PCM commands the solenoid “on” and the
voltage remains high (B+)or the PCM commands the
solenoid “off” and the voltage remains low (zero
volts).

D

All conditions met for 0.84 

∼

 1.0 seconds.

Action Taken When The DTC Sets

D

Fixed to 4th gear.

D

Maximum line pressure.

D

Inhibit TCC engagement.

D

The PCM will illuminate the Malfunction Indicator
Lamp (MIL) and CHECK TRANS Lamp.

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

Inspect the wiring for poor electrical connections at
the PCM and at the transmission 16–way connector.
Look for possible bent, backed out, deformed or
damaged terminals.  Check for weak terminal tension
as well.  Also check for a chafed wire that could short
to bare metal or other wiring.  Inspect for a broken wire
inside the insulation.

7A1–72 TRANSMISSION CONTROL SYSTEM (4L30–E)

D

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Test Description

The numbers below refer to the step numbers on the
diagnostic chart:
5. This test measures the resistance of the component.
7. This test checks the function of the shift solenoid B

and the transmission internal wiring harness.

11.This test checks for power to the shift solenoid B

from the ignition through the PCM.

Shift Solenoid Status Chart

Gear

Shift solenoid A

Shift solenoid B

1st

OFF

ON

2nd

ON

ON

3rd

ON

OFF

4th

OFF

OFF

DTC P0758 Shift Solenoid B Electrical 

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 “on”, 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”.

Were DTCs P0753, P0758, P1860 set?

Go to Step 4

Go to Step 3

3

1. The engine “on”.
2. Apply brake pedal and select transmission range “D”.
3. Press and hold down the winter switch and select transmission

mode “winter”.

Does the scan tool display DTC P0758 at 3rd gear?

Go to Step 8

Go to Diagnostic

Aids

4

1. Turn the ignition “off”.
2. Disconnect the J1 (BLUE) and J2 (RED) PCM connectors.
3. Turn the ignition “on”.
4. Using the J39200 DVOM, measure the voltage between PCM

connector terminals J2–31 and J1–1.

Is the voltage within 10 – 12 volts?

Go to Step 15

Go to Step 5

5

1. Turn the ignition “off”.
2. Using the J39200 DVOM, measure the resistance between

PCM connector terminals J2–43 and J2–31.

Is the resistance within 18 – 20 ohms?

Go to Step 16

Go to Step 6

6

1. Disconnect the transmission 16–way connector H–56.
2. Using the J39200 DVOM, measure the resistance between

terminals H56–11 and H56–12.

Is the resistance within 18 – 20 ohms?

Go to Step 17

Go to Step 7

7

1. Disconnect the transmission main case connector M–7.
2. Using the J39200 DVOM, measure the resistance between

terminals M7–2(D) and M7–6(A).

Is the resistance within 18 – 20 ohms?

Go to Step 18

Go to Step 19

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–73

DTC P0758 Shift Solenoid B Electrical  (Cont’d)

Step

No

Yes

Action

8

1. Turn the ignition “off”.
2. Disconnect the J1 (BLUE) and J2 (RED) PCM connectors.
3. Using the J39200 DVOM, measure the resistance between

PCM connector terminals J2–43 and J2–31.

Is the resistance within 18 – 20 ohms?

Go to Step 9

Go to Step 10

9

Using the J39200 DVOM, check a continuity between PCM
connector terminal J2–31 and ground.

Is there a continuity?

Go to Step 20

Go to Step 11

10

1. Disconnect the transmission 16–way connector H–56.
2. Using the J39200 DVOM, measure the resistance between

terminals H56–11 and H56–12.

Is the resistance within 18–20 ohms?

Go to Step 21

Go to Step 12

11

Using the J39200 DVOM, check a continuity between PCM
connector terminal J2–43 and ground.

Is there a continuity?

Go to Step 22

Go to Step 13

12

1. Disconnect the transmission main case connector M–7.
2. Using the J39200 DVOM, measure the resistance between

terminals M7–2(D) and M7–6(A).

Is the resistance within 18 – 20 ohms?

Go to Step 23

Go to Step 24

13

Check every connection of the PCM and transmission 16–way
connector H–56.

Was a problem found and corrected?

Go to Step 26

Go to Step 14

14

1. Connect the J1 (BLUE) and J2 (RED) PCM connectors to the

PCM.

2. Turn the ignition “on”, the engine “on”.
3. Repeat Step 3.

Does the scan tool display DTC P0758 at 3rd gear?

Go to Step 25

Go to Diagnostic

Aids

15

The wiring harness between PCM connector terminal
J2–31 and transmission main case terminal M7–6(A) is shorted to
voltage.

Was a problem found and corrected?

Go to Step 26

—

16

The PCM internal terminal J2–31 is shorted to voltage.
Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30–E) section.

Is the replacement complete?

Go to Step 26

—

17

The wiring harness between PCM connector and transmission
16–way connector is shorted.

Was a problem found and corrected?

Go to Step 26

—

18

The wiring harness between transmission 16–way connector and
transmission main case connector is shorted.

Was a problem found and corrected?

Go to Step 26

—

19

The shift solenoid B is faulty, or the internal wiring harness from
the shift solenoid B is shorted.

Was a problem found and corrected?

Go to Step 26

—

20

The wiring harness between PCM connector terminal
J2–31 and transmission main case connector terminal M7–6(A) is
shorted to ground.

Was a problem found and corrected?

Go to Step 26

—