Isuzu KB P190. Manual — part 968

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–86

Step Action

Yes

No

14 Perform the following procedure to verify the repair:

1

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.

2

Follow the instructions on Tech 2 and clear any DTCs.

3

On Tech 2 select:
Automatic Transmission / Data Display / Transmission Data.

4

Operate the vehicle under the following conditions:

•

Drive the vehicle in D4, with the TCC on, and a throttle
position at 20%.

•

On Tech 2 ensure the TCC Slip Speed is -20 to +50 RPM
for at least 7 seconds.

5

On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.

Has DTC P0894 set?

Go to Step 2

Go to Step 15

15 On Tech 2 select:

Diagnostic Trouble Codes / Read DTC Information.

Does Tech 2 display any DTCs you have not diagnosed?

Refer to

4.8 Diagnostic

Trouble Code List

System OK

When all diagnosis and repairs are completed, check the system for correct operation.

4.27 DTC P0961 – Line Pressure Control

Solenoid System Performance

DTC Description

This diagnostic procedure supports DTC P0961 Line Pressure Control (PC) Solenoid System Performance.

Circuit Description

The pressure control (PC) solenoid valve is an electronic device that regulates transmission line pressure based on the
current flow through its coil winding. The magnetic field produced by the coil moves the solenoid's internal valve, which
varies pressure to the pressure regulator valve. The transmission control module (TCM) controls the PC solenoid valve
by applying a varying amount of current to the solenoid. The applied current can vary from 0.1 – 1.1 A. Low current,
0.1 A, indicates high line pressure. High current, 1.1 A, indicates low line pressure. The duty cycle of the PC solenoid
valve is expressed as a percentage of energised on time. Zero percent indicates zero on time, non-energised, or no
current flow. Approximately 60 percent at idle indicates maximum on time, energised, or high current flow. The TCM
determines the appropriate line pressure for a given load by comparing the throttle position, the engine speed and other
inputs.

When the TCM detects a continuous open or short to ground in the PC solenoid valve circuit, then DTC P0961 sets.
DTC P0961 is a type C DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.

Conditions for Running the DTC

•

The system voltage is 8 – 18 V.

•

The engine is running.

Conditions for Setting the DTC

The PC solenoid valve duty cycle reaches its high limit, approximately 95 percent, or low limit, approximately 2 percent.

Action Taken When the DTC Sets

•

The TCM does not request the engine control module (ECM) to illuminate the MIL.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–87

•

The TCM records the operating conditions when the conditions for setting the DTC are met. The TCM records this
information as a Failure Record.

•

The TCM freezes transmission adaptive functions.

•

The TCM commands maximum line pressure.

•

The TCM stores DTC P0961 in TCM history.

Conditions for Clearing the DTC

•

The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission
related diagnostic fault occurring.

•

Tech 2 can clear the DTC.

Diagnostic Aids

DTC P0961 may set under low voltage conditions caused by high electrical system demands.

Test Description

The following numbers refer to the step numbers in the diagnostic table:

2

Checks the ability of the TCM to control the solenoid.

3

Checks the resistance of the control valve body wiring harness and the PC solenoid.

5

Checks the serviceability of the PC solenoid circuits contained in the control valve body wiring harness.

6-8 Checks the serviceability the power and signal circuits between the TCM and the transmission.

DTC P0961 Diagnostic Table

Step Action

Yes

No

1

Has the Diagnostic System Check been performed?

Go to Step 2

Refer to

4.7 Diagnostic

System Check

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–88

Step Action

Yes

No

2

1

Connect Tech 2 to the DLC.

2

Turn on the ignition, with the engine off.

N O T E

Before clearing the DTC, use the Tech

2 Freeze

Frame/Failure Record to record the transmission
parameters at the time the DTC set. Using Tech 2 to clear
the DTC(s) erases the Freeze Frame/Failure Record
records from the TCM.

3

On Tech 2 select:
Transmission / Automatic Transmission / Diagnostic
Trouble Codes / Freeze Frame.

4

Select the relevant DTC and note the parameters at the time of
the DTC setting.

5

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.

6

Follow the instructions on Tech 2 and clear the DTCs.

7

On Tech 2 select:
Miscellaneous Tests / Pressure Control Solenoid.

8

Using Tech 2, turn the pressure control solenoid on and off three
times.

Does Tech 2 display the PCS as On and Off when commanded by
Tech 2?

Check for an

intermittent fault in

the circuit, refer to

8A Electrical-Body

and Chassis

Go to Step 3

3

1

Turn off the ignition.

2

Disconnect connector E-95 from the transmission.

3

Install Tool No. J 44152 Jumper Harness (20 pins) on to the
transmission connector E-95.

4

Using the multimeter set to measure resistance, probe across
transmission connector E-95 pins 1 and 2.

Does the multimeter display 3 – 7

Ω?

Go to Step 4

Go to Step 5

4

Using the multimeter set to measure resistance, probe between
connector E-95 pin 2 and the transmission case.

Does the multimeter display greater than 250 k

Ω?

Go to Step 6

Go to Step 5

5

Using a multimeter, test between E-95 pin 1 & E-95 pin 2 and the
solenoid for the following:

•

open circuit,

•

short together, and

•

short to ground.

Did you find any of the conditions tested?

Replace the control

valve body wiring

harness, refer to

7C4 Automatic

Transmission –

4L60E – On-vehicle

Servicing.

Go to Step 11

Replace the PC

solenoid valve, refer

to 7C4 Automatic

Transmission –

4L60E – On-vehicle

Servicing

Go to Step 11

6

1

Disconnect Tool No. J 44152 from connector E-95.

2

Connect E-95 to the transmission.

3

Disconnect connector E-95 from the TCM.

4

Using a multimeter set to measure resistance, probe between
connector C-96 pins 17 and 40.

Does the multimeter display 3 – 7

Ω?

Go to Step 7

Go to Step 8

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–89

Step Action

Yes

No

7

Using a multimeter set to measure resistance, probe between
connector C-96 pin 40 and a known ground.

Does the multimeter display greater than 250 k

Ω?

Go to Step 9

Go to Step 8

8

Using a multimeter, test between E-95 pin 2 & C-96 pin 40 and
E-95 pin 1 & C-96 pin 17 for the following:

•

open circuit,

•

short together, and

•

short to ground.

Did you find any of the conditions tested?

Repair or replace

the affected circuit

Go to Step 11

—

9

Using a multimeter, test between E-95 pin 1 & E-95 pin 2 and the
solenoid for a short to voltage.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

10 Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –

On-vehicle Servicing.

Did you complete the replacement?

Go to Step 11

—

11 Perform the following procedure to verify the repair:

1

On Tech 2 select:
Diagnostic Trouble Codes / Clear Engine & Transmission
DTCs.

2

Follow the instructions on Tech 2 and clear any DTCs.

3

On Tech 2 select:
Data Display / Pressure Control Solenoid Data.

4

Start the engine and ensure the difference on Tech 2 between
the PCS Actual Current and the PCS Desired Current is less
than 16 mA.

5

On Tech 2 select:
Diagnostic Trouble Codes / Read DTC Information.

Has DTC P0961 set?

Go to Step 2

Go to Step 20

12 On Tech 2 select:

Diagnostic Trouble Codes / Read DTC Information.

Does Tech 2 display any DTCs you have not diagnosed?

Refer to

4.8 Diagnostic

Trouble Code List

System OK

When all diagnosis and repairs are completed, check the system for correct operation.

4.28 DTC P0973 – 1-2 Shift Solenoid Control

Circuit Low Voltage

DTC Description

This diagnostic procedure supports DTC P0973 1-2 Shift Solenoid (SS) Control Circuit Low Voltage.

Circuit Description

The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-
open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows four different shifting combinations. The solenoid
attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through the ignition
voltage circuit. The transmission control module (TCM) controls the solenoid by providing the ground path on the 1-2 SS
valve control circuit.

When the TCM detects a continuous open or short to ground in the 1-2 SS valve circuit, then DTC P0973 sets.
DTC P0973 is a type B DTC.