Isuzu KB P190. Manual — part 960

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–54

DTC P0723 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

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

Raise and support the rear axle assembly, refer to 0A General
Information.

8

Start the engine.

9

Disable the traction control system.

10

Place the transmission in D3 range.

11

With the drive wheels rotating, slowly accelerate to 2,000 r.p.m.
and hold. Road test the vehicle if necessary.

12

On Tech 2 select:
Data Display / Transmission Data.

With the drive wheels rotating, does the Tech 2 AT Output Speed
parameter drop or fluctuate more than 1,300 r.p.m.?

Go to Step 3

Check for an

intermittent fault in

the circuit, refer to

8A Electrical-Body

and Chassis

3

1

Turn off the ignition.

2

Disconnect connector E-44 from the sensor.

3

Using a multimeter set to measure resistance, probe across the
speed sensor pins 1 and 2.

Does the multimeter display 976 – 2354

Ω?

Go to Step 4

Go to Step 7

4

1

Using a multimeter set to measure resistance, probe between
connector E-44 pin 1 and a known ground.

2

Using a multimeter set to measure resistance, probe between
connector E-44 pin 2 and a known ground.

Does the multimeter display greater than 50 k

Ω in both instances?

Go to Step 5

Go to Step 7

5

1

Place the transmission in neutral.

2

Using a multimeter set to measure AC voltage, probe across the
speed sensor pins 1 and 2.

3

Rotate a rear wheel by hand.

Does the multimeter display 0.3 V AC?

Go to Step 6

Go to Step 7

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–55

Step Action

Yes

No

6

1

Disconnect connector C-96 from the TCM.

2

Test circuits speed sensor circuits (between C-96 pin 16 and
E-44 pin 2; C-96 pin 41 and E-44 pin 1) for the following
conditions:

•

Short to ground,

•

Short to battery,

•

Open circuit, and

•

Short together.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

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

Did you complete the replacement?

Go to Step 9

—

8

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

Did you complete the replacement?

Go to Step 9

—

9

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 / Transmission Data.

4

Operate the vehicle ensuring the transmission output speed
drop is less than 500 r.p.m. for 2 seconds and output speed is
greater than 500 r.p.m.

5

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

Has DTC P0723 set?

Go to Step 2

Go to Step 10

10 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.

4.17 DTC P0724 – Brake Switch Circuit Low

Input (Stuck Off)

DTC Description

This diagnostic procedure supports DTC P0724 Brake Switch Circuit Low Voltage.

Circuit Description

The transmission control module receives 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 an open or short to ground on the stop lamp signal circuit during stopping then DTC P0724 sets.
DTC P0724 is a type C DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–56

Conditions for Running the DTC

•

No DTCs P0719, P0722 or P0723.

•

The vehicle speed is greater than 40 km/h for 7 seconds, then 8 – 40 km/h for 5 seconds, then less than 8 km/h.

•

Continuously eight times once the previous criteria have been met.

Conditions for Setting the DTC

The TCM detects an open or short to ground on the stop lamp switch signal circuit when the circuit should be high,
battery voltage.

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 P0724 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

• Verify 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.

Test Description

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

3

Checks if the stop lamp switch is serviceable.

4

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

DTC P0724 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.

4

Press the brake pedal.

Does the Stop Lamp Pedal Switch parameter indicate Active?

Check for an

intermittent fault in

the circuit, refer to

8A Electrical-Body

and Chassis

Go to Step 3

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–57

Step Action

Yes

No

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.

3

Press the brake pedal.

Does the multimeter display battery voltage?

Go to Step 5

Repair or replace

affected circuit

Go to Step 6

5

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

Did you complete the replacement?

Go to Step 6

—

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 then brake, eight times in one
ignition cycle.

4

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

Has DTC P0724 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.

4.18 DTC P0741 – Torque Converter Clutch

System – Stuck Off

DTC Description

This diagnostic procedure supports DTC P0741 Torque Converter Clutch (TCC) System - Stuck Off.

Circuit Description

The torque converter clutch (TCC) solenoid valve is a normally-open exhaust valve that is used with the torque converter
clutch pulse width modulation (TCC PWM) solenoid valve to control fluid acting on the converter clutch apply valve. The
TCC solenoid valve attaches to the transmission case assembly extending into the pump cover. When grounded by the
transmission control module (TCM), the TCC solenoid valve stops converter signal oil from exhausting. This causes
converter signal oil pressure to increase and move the converter clutch apply valve against spring force and into the
apply position. In this position, release fluid is open to an exhaust port and converter feed fluid fills the apply fluid circuit.
The converter feed fluid applies the TCC. When the TCM no longer provides a ground path, the TCC solenoid valve de-
energizes and apply fluid exhausts, releasing the TCC.

When the TCM detects high torque converter slip when the TCC is commanded off, then DTC P0741 sets. DTC P0741 is
a type B DTC.

Refer to 2

Wiring Diagrams and Connector Chart to aid in diagnosis.