Isuzu KB P190. Manual — part 958

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–46

Step Action

Yes

No

3

Inspect the transmission and related components for the following:

•

transmission fluid level,

•

transmission fluid cooling system restrictions / blockages,

•

debris in the transmission fluid,

•

incorrect line pressure,

•

torque converter stator operation, and

•

transmission overload.

Was a fault found and rectified?

Go to Step 10

Check for an

intermittent fault in

the circuit, refer to

8A Electrical-Body

and Chassis

4

1

Switch off the ignition.

2

Disconnect connector E-95 from the transmission.

3

Using a multimeter set to measure voltage, probe between
harness connector E-95 pin 16 and a known ground.

Does the multimeter display 4.8 – 5.2 V?

Go to Step 6

Go to Step 5

5

Test the TFT sensor signal circuit (between connectors E-95 pin 16
and C-96 pin 35) for a high resistance, open circuit, short to ground or
short to voltage fault condition.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

6

1

Switch off the ignition.

2

Remove the TCM fuses C-8 and EB-4, refer to 8A Electrical-
Body and Chassis.

3

Using a multimeter set to measure resistance, probe between
connector E95 pin 15 and a known ground.

Does the multimeter display less than 5

Ω?

Go to Step 8

Go to Step 7

7

Using a multimeter, test between E-95 pin 15 and C-96 pin 30 for high
resistance, open circuit, short to ground or short to voltage fault
condition.

Was any fault found and rectified?

Go to Step 10

—

8

Replace the TFT sensor, refer to 7C4 Automatic Transmission –
4L60E – On-vehicle Servicing.

N O T E

Check for damaged wiring (short to ground, short to
voltage, high resistance or open circuit) or poor
connections inside the transmission assembly before
replacing the TFT sensor.

Was the repair complete?

Go to Step 10

—

9

Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Servicing

Was the repair completed?

Go to Step 10

—

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–47

Step Action

Yes

No

10 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

Start the engine.

4

Operate the vehicle within the conditions for running the DTC or
within the conditions in the Failure Records.

5

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

Have any of the DTCs in this procedure set?

Go to Step 2

Go to Step 11

11 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.

4.14 DTC P0719 – Brake Switch Circuit High

Input (Stuck On)

DTC Description

This diagnostic procedure supports DTC P0719 Brake Switch Circuit High Voltage.

Circuit Description

The transmission control module (TCM) has a direct input from the stop lamp switch assembly. When the brake pedal is
pressed, 12 V is supplied to the TCM through connector C-96 pin 42.

When the TCM detects a voltage on the stop lamp switch signal circuit during acceleration, then DTC P0719 sets.
DTC P0719 is a type C DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.

Conditions for Running the DTC

•

No DTCs P0722, P0723 or P0724.

•

The vehicle speed is 8 – 40 km/h for 6 seconds, then greater than 40 km/h for 7 seconds.

Conditions for Setting the DTC

The TCM detects voltage on the stop lamp switch signal circuit during acceleration.

Action Taken When the DTC Sets

•

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

•

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 stores DTC P0719 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.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–48

Diagnostic Aids

• Verify if the brake pedal position sensor is

adjusted properly, refer to 8B Cruise
Control.

• Test drive the vehicle if a switch or circuit

condition cannot be located. An
intermittent condition may be duplicated
during a test drive.

• Application of the brake pedal while

accelerating may cause this DTC to set.

Test Description

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

2

Checks the stop lamp switch is serviceable.

4

Checks if there is a stop lamp switch signal to the TCM.

DTC P0719 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

2

1

Connect Tech 2 to the DLC.

2

On Tech 2 select:
Engine / V6 Engine / Data Display / Cruise / Traction Data.

3

Turn on the ignition, with the engine off.

N O T E

Ensure the brake pedal is in the rest position.

Does the Stop Lamp Pedal Switch parameter indicate Inactive?

Check for an

intermittent fault in

the circuit, refer to

8A Electrical-Body

and Chassis

Go to Step 3

3

Test the stop lamp switch assembly, refer to 8B Cruise Control.

Is the stop lamp switch assembly serviceable?

Go to Step 4

Replace the stop

lamp switch

assembly.

4

1

Disconnect connector C-96 from the TCM.

2

Using a multimeter set to measure voltage, probe between
harness connector C-96 pin 42 and a known ground.

N O T E

Ensure the brake pedal is in the rest position.

Does the multimeter display battery voltage?

Repair or replace

affected circuit

Go to Step 6

Go to Step 5

5

Replace the TCM, refer to 7C4 Automatic Transmission – 4L60E –
On-vehicle Service.

Did you complete the replacement?

Go to Step 6

—

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–49

Step Action

Yes

No

6

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

Operate the vehicle under the following conditions:

•

Turn on the ignition, with the engine off for at least
2 seconds.

•

Start the vehicle and idle for 5 seconds.

•

Drive in D4 from 0 – 60 km/h 8 times in 1 ignition cycle.

4

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

Has DTC P0719 set?

Go to Step 2

Go to Step 7

7

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.

4.15 DTC P0722 – Vehicle Speed Sensor

Circuit Low Voltage

DTC Description

This diagnostic procedure supports DTC P0722 Vehicle Speed Sensor Circuit Low Voltage.

Circuit Description

The vehicle speed sensor (VSS) provides vehicle speed information to the transmission control module (TCM). The VSS
is a permanent magnet generator. The sensor is mounted in the extension housing facing the rear internal gear which is
splined to the output shaft assembly. As the output shaft and internal gear rotate, the toothed rotor of the internal gear
produces AC voltage as the rotor teeth pass through the magnetic field of the sensor. The AC voltage level and the
number of pulses increase as the speed of the vehicle increases. The TCM converts the voltage to vehicle speed. The
TCM uses the output shaft speed signal to determine shift timing and torque converter clutch (TCC) scheduling.

If the TCM detects no vehicle speed when there is engine speed in a drive gear range, then DTC P0722 sets.
DTC P0722 is a type B DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.

Conditions for Running the DTC

•

No DTCs P0723, P1810, P1815 or P1816.

•

Ignition voltage is 8 – 18 V.

•

TFT is -40°C – 150°C.

•

The engine run time is greater than 5 seconds.

•

The throttle position is greater than 12 percent.

•

The engine torque is 108 – 882 Nm.

Conditions for Setting the DTC

The transmission output shaft speed is less than 50 r.p.m. for 3 seconds.