Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 441

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

DTC P0758 Shift Solenoid B Electrical  (Cont’d)

Step

No

Yes

Action

11

Check every connection of the PCM.

Was a problem found and corrected?

Go to 

Step 22

Go to 

Step 12

12

1. Connect the E-34 (BLUE) and E-35 (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 21

Go to 

Diagnostic
Aids

13

The wiring harness between PCM connector terminal
E35–31 and transmission main case terminal E42–6(A) is shorted
to voltage.

Was a problem found and corrected?

Go to 

Step 22

—

14

The PCM internal terminal E35–31 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 22

—

15

The wiring harness between PCM connector and transmission
main case 7-way connector is shorted.

Was a problem found and corrected?

Go to 

Step 22

—

16

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 22

—

17

The wiring harness between PCM connector terminal
E35–31 and transmission main case connector terminal
E42–6(A) is shorted to ground.

Was a problem found and corrected?

Go to 

Step 22

—

18

The wiring harness between PCM connector terminal E35–43
and transmission main case connector terminal E42–2(D) is
shorted to ground.

Was a problem found and corrected?

Go to 

Step 22

—

19

The wiring harness between PCM connector terminal E35–31
and transmission main case connector terminal E42–6(A), or
between PCM connector terminal E35–43 and main case
connector terminal E42–2(D) is open.

Was a problem found and corrected?

Go to 

Step 22

—

20

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

Was a problem found and corrected?

Go to 

Step 22

—

21

Replace the PCM.

Is the replacement complete?

Go to 

Step 22

—

22

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

then “Clear Info” function and operate the vehicle under the
following conditions:

D

The shift solenoid B is commanded “on” and voltage drops to
zero.

D

The shift solenoid B is commanded “off” and voltage
increases to B+.

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)

7A1–75

DTC P1850 Brake Band Apply Solenoid Malfunction

D07R200010

Circuit Description

D

The brake band apply solenoid is a normally open
solenoid which controls the flow of fluid for brake band
application.  The Powertrain Control Module (PCM)
uses Pulse Width Modulation (PWM) and changes
the duty cycle to control the solenoid.  The PCM turns
the solenoid on (energized) and off (deenergized) at a
constant frequency.  The length of time the solenoid is
energized during each on/off cycle is called the pulse
width.  By varying or “modulating” the pulse width, the
solenoid output pressure is changed.  Since the
solenoid is normally open, increasing the pulse width
increases the duty cycle and decreases the output
pressure.  PWM control provides smooth band
application without an accumulator.  The band is only
applied in first and second gears.

D

In the event of an electrical failure (open), the
solenoid regulates at the maximum oil flow (0% duty
cycle).

D

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).

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. When the ignition
is off, the HSD is turned off.

This DTC detects a continuous open or short to ground in
the brake band apply solenoid circuit or the brake band
apply solenoid.  This is a type “D” DTC.

Conditions For Setting The DTC

D

Battery voltage is between 10 and 16 volts.

D

Ignition is “on”, Engine “run”.

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 in 1.34 

∼

 1.56 seconds.

Action Taken When The DTC Sets

D

Inhibit brake band apply solenoid.

D

The PCM will not illuminate the Malfunction Indicator
Lamp (MIL).

Conditions For Clearing The DTC

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.

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

Diagnostic Aids

D

Inspect the wiring for poor electrical connection at the
PCM and at the transmission 7–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.

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:
3. This test checks for power to the brake band apply

solenoid from the ignition through the PCM.

4. This test checks the resistance of the transmission

internal wiring harness and brake band apply
solenoid.

5. This test checks the ability of the PCM and wiring to

control the ground circuit.

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–77

DTC P1850 Brake Band Apply Solenoid Malfunction 

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

Emission 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 set?

Go to 

Step 3

Go to 

Step 4

3

Using the J39200 DVOM, back probe between PCM connector
terminals E35–43 and E35–1.

Is the voltage between 10 to 12 volts?

Go to 

Step 5

Go to 

Step 6

4

1. Turn the ignition “off”.
2. Disconnect the E-34 (BLUE) and E-35 (RED) PCM connector.
3. Using the J39200 DVOM, measure the resistance between

PCM connector terminals E35–43 and E35–10.

Is the resistance within 10–12 ohms?

Go to 

Step 10

Go to 

Step 11

5

Using the J39200 DVOM, back probe between PCM connector
terminals E35–10 and E35–1.

Is the voltage between 10 to 12 volts?

Go to 

Step 19

Go to 

Step 4

6

1. Turn the ignition “off”.
2. Disconnect the E-34 (BLUE) and E-35 (RED) PCM connector.
3. Using the J39200 DVOM, check continuity between PCM

terminal E35–43 and ground.

Is there a continuity?

Go to 

Step 7

Go to 

Step 8

7

1. Disconnect the transmission main case connector E-42.
2. Using the J39200 DVOM, check continuity between the

terminal E42–7(B) and ground.

Is there continuity?

Go to 

Step 13

Go to 

Step 14

8

1. Disconnect the E-34 (BLUE) and E-35 (RED) PCM Connector.
2. Using the J39200 DVOM, measure the resistance between

the PCM connector terminals E35–43 and E35–10.

Is the resistance within 10–12 ohms?

Go to 

Step 19

Go to 

Step 9

9

1. Disconnect the transmission main case connector E-42.
2. Using the J39200 DVOM, measure the resistance between

the terminals E42–7(B) and E42–2(D).

Is the resistance within 10–12 ohms?

Go to 

Step 15

Go to 

Step 16

10

Using the J39200 DVOM, check continuity between PCM
terminal E35–10 and ground.

Is there continuity?

Go to 

Step 12

Go to 

Step 19

11

1. Disconnect the transmission main case connector E-42.
2. Using the J39200 DVOM, measure the resistance between

the terminals E42-7(B) and E42-2(D).

Is the resistance within 10–12 ohms?

Go to 

Step 18

Go to 

Step 16