Hummer H2. Manual — part 2483

3

The TCC is hydraulically or mechanically
stuck OFF. Inspect for the following
conditions:

z

Inspect the TCC PWM valve for a
damaged exhaust orifice.

z

Inspect for the converter apply valve
being stuck in the OFF, release,
position.

z

Inspect for a misaligned or damaged
valve body gasket.

z

Inspect for a restricted apply valve
passage.

z

Inspect the torque converter clutch for
being mechanically stuck OFF.

Refer to Symptoms - Automatic
Transmission NO TCC apply.
Was the condition found?

-

Go to Step 4

-

4

Perform the following procedure in order to
verify the repair:

1. Select DTC.

2. Select Clear Info.

3. Drive the vehicle in D4 under the

following conditions:

Hold the throttle at 20-99% and
accelerate to 88 km/h (55 mph). Ensure
that the scan tool TCC Slip Speed is less
than 50 RPM for 5 seconds, with the
TCC ON.

4. Select Specific DTC.

5. Enter DTC P0741.

Has the test run and passed?

-

Go to Step 5

Go to Step 2

5

With the scan tool, observe the stored
information, capture info, and DTC Info.
Does the scan tool display any DTCs that you
have not diagnosed?

-

Go to Diagnostic

Trouble Code

(DTC) List in

Engine Controls -

6.0L (LQ4)

System OK

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

DTC P0742

Fig. 12: Torque Converter Clutch (TCC) Fluid Diagram
Courtesy of GENERAL MOTORS CORP.

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 in order 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, energized, by the powertrain control module (PCM), 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 PCM no longer provides a ground path, the TCC solenoid valve de-energizes and apply fluid
exhausts, releasing the TCC.

When the PCM detects low TCC slip speed when the TCC is commanded OFF, then DTC P0742 sets. DTC
P0742 is a type B DTC.

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

Conditions for Running the DTC

z

No TP sensor DTCs P0122 or P0123.

z

No VSS assembly DTCs P0502 or P0503.

z

No TCC solenoid valve DTC P0740.

z

No TFP manual valve position switch DTC P1810.

z

No TCC PWM solenoid valve DTC P2761.

z

The TP angle is 17-45 percent.

z

The engine speed is greater than 450 RPM for 6 seconds.

z

The engine is not in fuel cutoff.

z

The TFT is between 20-130°C (68-266°F).

z

The engine torque is 68-542 N.m (50-400 lb ft).

z

The engine speed is 1,000-3,000 RPM.

z

The speed ratio is 0.64 to 1.35.

z

The vehicle speed is 24-80 km/h (15-50 mph).

z

The gear range does not change within 5 seconds.

z

The commanded gear is not 1st.

z

The gear range is D4.

z

The TCC is commanded OFF.

Conditions for Setting the DTC

DTC P0742 sets if the following condition occurs twice.

The TCC slip speed is -20 to +20 RPM for 5 seconds.

Action Taken When the DTC Sets

z

The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which
the Conditions for Setting the DTC are met.

z

The PCM inhibits 4th gear in Hot Mode.

z

The PCM freezes transmission adapt functions.

z

The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM
stores this information as Freeze Frame and Failure Records.

z

The PCM stores DTC P0742 in PCM history during the second consecutive trip in which the Conditions
for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

z

The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and
passes.

z

A scan tool can clear the MIL/DTC.

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

z

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

z

The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power
down the PCM.

Diagnostic Aids

The TCC fluid hydraulically applies the TCC, possibly causing an engine stall, under the following conditions:

z

The TCC is hydraulically stuck ON

z

The parking brake is applied

z

Any gear range is selected

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2: This step tests the hydraulic state of the TCC. When the PCM commands the TCC solenoid valve OFF,
the slip speed should increase.

DTC P0742

Step

Action

Value

(s)

Yes

No

1

Did you perform the Diagnostic System Check
- Engine Controls?

-

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls in

Engine Controls -

6.0L (LQ4)

2

1. Install a scan tool.

2. Turn ON the ignition, with the engine

OFF.

3. Record the DTC Freeze Frame and

Failure Records.

4. Clear the DTC.

5. Drive the vehicle in the D4 drive range

in second, third or fourth gear under

IMPORTANT:

Before clearing the DTC, use the scan
tool in order to record the Freeze
Frame and Failure Records. Using the
Clear Info function erases the Freeze
Frame and Failure Records from the
PCM.

-20 to

+20

RPM

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2