Hummer H2. Manual — part 2501

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No TP sensor DTCs P0122, or P0123.

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No VSS assembly DTCs P0502 or P0503.

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No TCC solenoid valve DTC P0740.

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No TCC stuck ON DTC P0742.

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No 1-2 SS valve DTCs P0751 or P0753.

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No 2-3 SS valve DTCs P0756 or P0758.

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No TFP manual valve position switch DTC P1810.

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No TCC PWM solenoid valve DTC P2761.

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The engine speed is greater than 450 RPM for 5 seconds.

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The engine is not in fuel cutoff.

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The vehicle speed is greater than 11 km/h (7 mph).

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The TP angle is 17-50 percent.

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The engine torque is 54-542 N.m (40-400 lb ft).

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The gear range is D4.

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The shift solenoid performance counters are zero.

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The TFT is 20-130°C (68-266°F).

Conditions for Setting the DTC

DTC P2771 sets if one of the following conditions occurs:

Condition 1

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The 4WD low switch is in 4WD low.

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The transfer case is not in 4WD low.

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The TCC slip speed is -3,000 to -50 RPM.

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The transfer case ratio is 0.08-1.2, the transfer case ratio is the engine speed divided by the transfer case
output speed.

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All conditions are met for 5 seconds.

Condition 2

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The 4WD low switch is not in 4WD low.

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The transfer case is in 4WD low.

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The TCC is commanded ON.

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The TCC slip speed is 100 to 3,000 RPM.

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The transfer case ratio is 2.5-2.9.

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All conditions are met for 10 seconds.

Action Taken When the DTC Sets

2004 Hummer H2

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

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

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The PCM commands a normal shift pattern, not a 4WD low shift pattern.

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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.

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The PCM stores DTC P2771 in PCM history during the second consecutive trip in which the Conditions
for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

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

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A scan tool can clear the MIL/DTC.

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

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The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is
OFF long enough in order to power down the PCM.

Test Description

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

3: This step tests for a short to ground in the 4WD low signal circuit.

4: This step tests for an open in the 4WD low signal circuit or a faulty transfer case control module.

DTC P2771

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)

1. Install a scan tool.

2. Start the engine, parking brake disengaged.

3. Record the DTC Freeze Frame and Failure

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.

2004 Hummer H2

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

2

Records.

4. Clear the DTC.

5. Place the transmission in NEUTRAL.

6. Select 4HI on the transfer case selector.

7. Select 4LO on the transfer case selector.

Does the scan tool 4WD Low display Disabled
when you select 4HI, then Enabled when you
select 4LO?

IMPORTANT:

It may be necessary to drive the vehicle
slightly forward to engage 4LO on the
transfer case.

-

Go to Intermittent

Conditions in

Engine Controls -

6.0L (LQ4)

Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the transfer case control

module connector C1.

3. Turn ON the ignition, with the engine

OFF.

Does the scan tool 4WD Low indicate Enabled?

-

Go to Step 6

Go to Step 4

4

1. Connect C1-B5 of the transfer case control

module connector to ground.

2. Observe the scan tool 4WD Low.

Does the scan tool 4WD Low indicate Enabled
when the 4WD low signal circuit (1694), is
grounded?

-

Go to Step 5

Go to Step 7

5

Replace the transfer case control module.
Refer to Transfer Case Shift Control Module
Replacement in Transfer Case - BW - 4484.
Did you complete the replacement?

-

Go to Step 9

-

6

Test the 4WD low signal circuit for a short to
ground.
Refer to Testing for Short to Ground and
extxref document="029_body-21"
filetype="sgml" extrefid="i162420">Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 9

Go to Step 8

7

Test the 4WD low signal circuit for an open.
Refer to Testing for Continuity and extxref
document="029_body-21" filetype="sgml"
extrefid="i162420">Wiring Repairs in Wiring

-

2004 Hummer H2

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

Systems.
Did you find and correct the condition?

Go to Step 9

Go to Step 8

8

Replace the PCM.
Refer to Powertrain Control Module (PCM)
Replacement in Engine Controls - 6.0L (LQ4).
Did you complete the replacement?

-

Go to Step 9

-

9

Perform the following procedure in order to
verify the repair:

1. Select DTC.

2. Select Clear Info.

3. Operate the vehicle under the following

conditions:

1. Select 4LO on the transfer case

selector.

2. Drive the vehicle in D4.

3. Verify that the speed ratio is 2.5-2.9

for 1.5 seconds.

4. Select 2HI or 4HI on the transfer

case selector.

5. Drive the vehicle in D4 with the

TCC ON.

6. Verify that the speed ratio is 0.8-1.2

for 5 seconds.

4. Select Specific DTC.

5. Enter DTC P2771.

Has the test run and passed?

-

Go to Step 10

Go to Step 2

10

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