Hummer H1 (2006+). Manual - part 107

OBD-272

On-Board Diagnostics

_____________________________________________

    3

1.

Install the scan tool.

2.

Turn ON the ignition, with the engine OFF.

NOTE: Before clearing the DTC, use the scan tool in order to
record the Freeze Frame and Failure Records for reference. The
Clear Info function will erase the data.

3.

Record the DTC Freeze Frame and Failure Records.

4.

Clear the DTC.

5.

Using the scan tool, observe ignition voltage.

Is the voltage within the specified range?

9-18 Volts

Go to Step 4

Go to DTC 

P0562 for low 

voltage or DTC 

P0563 for high 

voltage

    4

1.

Drive the vehicle under normal operating conditions.

2.

Using the scan tool, monitor engine, turbine and output 
speed readings.

Is speed sensor data erratic?

Go to the appro-

priate speed sen-

sor DTC

Go to Step 5 

    5

Conduct a clutch test for third range. 

Did the turbine speed remain at zero?

Go to Diagnos-

tic Aids

Go to Step 6

    6

1.

Remove the transmission oil pan. Refer to Automatic Trans-
mission Fluid/Filter Replacement.

2.

Inspect for contaminated fluid and excessive material in the 
pan.

Is the fluid contaminated or excessive material found in the pan?

Go to Step 7

Go to Step 8

    7

Remove the transmission for overhaul or replacement. 

Did you complete the replacement?

Go to Step 10 

    8

Inspect for a stuck or sticking trim valve. 

Did you find and correct a condition?

Go to Step 10

Go to Step 9

    9

Replace the faulty pressure control (PC) solenoid A. 

Did you complete the replacement?

Go to Step 10 

    10

Perform the following procedure in order to verify the repair:

1.

Clear the DTC.

2.

Start the engine.

3.

Using the scan tool, monitor first gear ratio and operate vehi-
cle under normal operating conditions.

4.

Select Specific DTC.

5.

Enter DTC P0733.

Has the test run and passed?

System OK

Go to Step 1 

Step

Action

Value(s)

Yes

No

_____________________________________________

 On-Board Diagnostics  OBD-273

5745804

DTC P0734 Incorrect 4th Gear Ratio

Circuit Description

The transmission control module (TCM) uses input from the input speed sensor and output speed sensor to determine gear ratios.
The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

DTC P0734 is a type A DTC.

Conditions for Setting the DTC

DTC P0734 sets when the calculated 4th range ratio, steady state, differs from the known 4th range ratio.

Action Taken When the DTC Sets 

• The TCM illuminates the malfunction indicator lamp (MIL). 

• The transmission defaults to 5th range while diagnostic response is active. 

• If the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL. 

• If the shift selector is moved to REVERSE, the transmission will shift to REVERSE, unless the transmission is compro-

mised by a direction change. In that case, the transmission will shift to NEUTRAL. 

• If the shift selector is returned to a forward range and the transmission is compromised by over speeding or direction 

change, the transmission will lock in NEUTRAL. 

• DTC P0734 will be stored in TCM history. 

• The TCM freezes shift adapts. 

• TCM inhibits torque converter clutch (TCC) engagement. 

Conditions for Clearing the DTC

A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle com-
pletes 40 warm-up cycles without failure.

Diagnostic Aids 

• Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 1-2-3-4 clutch and 4th and 5th 

clutch, for 4th range. 

• Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid. 

• Clutch test mode can be used to observe stall speed. 

• You may have to drive the vehicle in order to experience a condition. 

Step

Action

Value(s)

Yes

No

    1

NOTE: Before clearing DTC(s) use the scan tool “Capture info”
to record Freeze Frame and Failure Records for reference, as data
will be lost when “Clear Info” function is used 

Was the “On-Board Diagnostic (OBD) System Check” per-
formed?

Go to step 2.

Go to OBD Sys-

tem Check.

    2

Measure the transmission fluid level. Refer to Transmission Fluid
Checking Procedure.

Is the transmission fluid level correct?

Go to Step 3 

Go to Transmis-

sion Fluid 

Checking Proce-

dure

OBD-274

On-Board Diagnostics

_____________________________________________

    3

1.

Install the scan tool.

2.

Turn ON the ignition, with the engine OFF.

NOTE: Before clearing the DTC, use the scan tool in order to
record the Freeze Frame and Failure Records for reference. The
Clear Info function will erase the data.

3.

Record the DTC Freeze Frame and Failure Records.

4.

Clear the DTC.

5.

Using the scan tool, observe ignition voltage.

Is the voltage within the specified range?

9-18 Volts

Go to Step 4

Go to DTC 

P0562 for low 

voltage or DTC 

P0563 for high 

voltage

    4

1.

Drive the vehicle under normal operating conditions.

2.

Using the scan tool, monitor engine, turbine and output 
speed readings.

Is speed sensor data erratic?

Go to the appro-

priate speed sen-

sor DTC

Go to Step 5 

    5

Conduct a clutch test for fourth range. 

Did the turbine speed remain at zero?

Go to Diagnos-

tic Aids

Go to Step 6

    6

1.

Remove the transmission oil pan. Refer to Automatic Trans-
mission Fluid/Filter Replacement.

2.

Inspect for contaminated fluid and excessive material in the 
pan.

Is the fluid contaminated or excessive material found in the pan?

Go to Step 7

Go to Step 8

    7

Remove the transmission for overhaul or replacement. 

Did you complete the replacement?

Go to Step 10 

    8

Inspect for a stuck or sticking trim valve. 

Did you find and correct a condition?

Go to Step 10

Go to Step 9

    9

Replace the faulty pressure control (PC) solenoid A. 

Did you complete the replacement?

Go to Step 10 

    10

Perform the following procedure in order to verify the repair:

1.

Clear the DTC.

2.

Start the engine.

3.

Using the scan tool, monitor first gear ratio and operate vehi-
cle under normal operating conditions.

4.

Select Specific DTC.

5.

Enter DTC P0734.

Has the test run and passed?

System OK

Go to Step 1 

Step

Action

Value(s)

Yes

No

_____________________________________________

 On-Board Diagnostics  OBD-275

5745804

DTC P0735 Incorrect 5th Gear Ratio

Circuit Description

The transmission control module (TCM) uses input from the input speed sensor and output speed sensor (OSS) to determine gear
ratios. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

DTC P0735 is a type A DTC.

Conditions for Setting the DTC

DTC P0735 sets when the calculated fifth range ratio, steady state, differs from the known fifth range ratio.

Action Taken When the DTC Sets 

• The TCM illuminates the malfunction indicator lamp (MIL). 

• The transmission defaults to 4th range while diagnostic response is active. 

• If the shift selector is moved to NEUTRAL, the transmission will shift to NEUTRAL. 

• If the shift selector is moved to REVERSE, the transmission will shift to REVERSE, unless the transmission is compro-

mised by a direction change. In that case, the transmission will shift to NEUTRAL. 

• If the shift selector is returned to a forward range and the transmission is compromised by over speeding or direction 

change, the transmission will lock in NEUTRAL. 

• DTC P0735 will be stored in TCM history. 

• The TCM freezes shift adapts. 

• The TCM inhibits torque converter clutch (TCC) engagement. 

Conditions for Clearing the DTC

A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle com-
pletes 40 warm-up cycles without failure.

Diagnostic Aids 

• Incorrect ratio codes typically indicate mechanical conditions with specific clutches, such as 4th and 5th clutch and 3rd, 5th,

and Reverse clutch, for 5th range. 

• Incorrect ratio code could indicate a hydraulically failed solenoid. Observe DTC information for specific solenoid. 

• Clutch test mode can be used to observe stall speed. 

• You may have to drive the vehicle in order to experience a condition. 

Step

Action

Value(s)

Yes

No

    1

NOTE: Before clearing DTC(s) use the scan tool “Capture info”
to record Freeze Frame and Failure Records for reference, as data
will be lost when “Clear Info” function is used 

Was the “On-Board Diagnostic (OBD) System Check” per-
formed?

Go to step 2.

Go to OBD Sys-

tem Check.

    2

Measure the transmission fluid level. Refer to Transmission Fluid
Checking Procedure.

Is the transmission fluid level correct?

Go to Step 3 

Go to Transmis-

sion Fluid 

Checking Proce-

dure