Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1588

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–77

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.

7A1–78 TRANSMISSION CONTROL SYSTEM (4L30–E)

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 J2–43 and J2–1.

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 J1 (BLUE) and J2 (RED) PCM connector.
3. Using the J39200 DVOM, measure the resistance between

PCM connector terminals J2–43 and J2–10.

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 J2–10 and J2–1.

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 J1 (BLUE) and J2 (RED) PCM connector.
3. Using the J39200 DVOM, check continuity between PCM

terminal J2–43 and ground.

Is there a continuity?

Go to Step 7

Go to Step 8

7

1. Disconnect the transmission main case connector E–54.
2. Using the J39200 DVOM, check continuity between the

terminal E54–7(B) and ground.

Is there continuity?

Go to Step 13

Go to Step 14

8

1. Disconnect the J1 (BLUE) and J2 (RED) PCM Connector.
2. Using the J39200 DVOM, measure the resistance between

the PCM connector terminals J2–43 and J2–10.

Is the resistance within 10–12 ohms?

Go to Step 19

Go to Step 9

9

1. Disconnect the transmission main case connector E–54.
2. Using the J39200 DVOM, measure the resistance between

the terminals E54–7(B) and E54–2(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 J2–10 and ground.

Is there continuity?

Go to Step 12

Go to Step 19

11

1. Disconnect the transmission main case connector E–54.
2. Using the J39200 DVOM, measure the resistance between

the terminals E54–7(B) and E54–2(D).

Is the resistance within 10–12 ohms?

Go to Step 18

Go to Step 16

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–79

DTC P1850 Brake Band Apply Solenoid Malfunction  (Cont’d)

Step

No

Yes

Action

12

1. Disconnect the transmission main case connector E–54.
2. Using the J39200 DVOM, check continuity between the

terminals E54–7(B) and ground.

Is there a continuity?

Go to Step 13

Go to Step 17

13

The brake band apply solenoid is faulty, or the internal wiring
harness from the brake band apply solenoid is shorted to ground.

Was a problem found and corrected?

Go to Step 20

—

14

The wiring harness between the PCM connector terminal J2–43
and the transmission main case connector terminal E54–2(D) is
shorted to ground.

Was a problem found and corrected?

Go to Step 20

—

15

The wiring harness between the PCM connector terminal J2–43
and the transmission main case connector terminal E54–2(D) is
open.

Was a problem found and corrected?

Go to Step 20

—

16

The brake band apply solenoid is faulty, or the internal wiring
harness from the brake band apply solenoid is open.

Was a problem found and corrected?

Go to Step 20

—

17

The wiring harness between the PCM connector terminal J2–10
and the transmission main case connector terminal E54–7(B) is
shorted ground.

Was a problem found and corrected?

Go to Step 20

—

18

The wiring harness between the PCM connector terminal J2–10
and the transmission main case connector terminal E54–7(B) is
open.

Was a problem found and corrected?

Go to Step 20

—

19

Check every connection at the PCM.
If OK, replace the PCM. Refer to Powertrain Control Module
(PCM) in Automatic Transmission (4L30–E) section.

Is the replacement complete?

Go to Step 20

—

20

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

then “Clear Info” function and ensure the following conditions
are met:

D

The brake band apply solenoid is commanded “on” and the
volts drop to zero.

D

The brake band apply solenoid is commanded “off” and the
volts increase 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

7A1–80 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P1860 TCC Solenoid Electrical

D07RY00036

Circuit Description

The PCM allows current to flow through the solenoid (0 or
12 volts).  This current flow through the solenoid coil
creates a magnetic field that magnetizes the solid core.
The magnetized core attracts the check ball to seat
against spring pressure.  This blocks the exhaust for the
TCC signal fluid and allows solenoid feed drive fluid to
feed to TCC signal circuit.  The TCC signal fluid pressure
acts on the torque converter clutch control valve.  When
the TCC control valve is in the apply position, line
pressure is directed through the TCC valve to apply the
torque converter clutch. The TCC solenoid is attached to
the valve body within the transmission.
This DTC detects a continuous open or short to ground or
ignition in the TCC circuit or the TCC solenoid.  This is a
type “B” DTC.

Conditions For Setting The DTC

D

Battery voltage is between 10 and 16 volts.

D

No shift solenoid A DTCs P0751 or P0752 or P0753.

D

No shift solenoid B DTCs P0756 or P0757 or P0758.

D

Ignition “on”. Engine “run”.

D

The PCM commands the solenoid “on” and the
voltage remains low (zero volts).

D

The PCM commands the solenoid “off” and the
voltage remains high (B+).

D

All conditions met for 0.875 

∼

 1.25 seconds.

Action Taken When The DTC Sets

D

Inhibit TCC engagement.

D

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

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 4–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 voltage to the solenoid.
4. This test checks the ability of the PCM and wiring to

control the ignition circuit.

8. This test checks the resistance of the TCC solenoid

and the internal wiring harness.