Hummer H1 (2006+). Manual — part 108

OBD-276

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 fifth 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 P0735.

Has the test run and passed?

System OK

Go to Step 1

Step

Action

Value(s)

Yes

No

_____________________________________________

On-Board Diagnostics OBD-277

5745804

DTC P0736 Incorrect Reverse 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 gear.

DTC P0736 is a type A DTC.

Conditions for Setting the DTC

DTC P0736 sets when the calculated REVERSE range ratio, steady state, detected by the TCM differs from the known REVERSE
range ratio.

Action Taken When the DTC Sets

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

• The transmission will lock in NEUTRAL.

• DTC P0736 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 3rd, 5th, and Reverse clutch

and Low and Reverse clutch for REVERSE range.

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

• 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-278

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.

Start the engine.

2.

Select REVERSE range.

3.

Using the scan tool, observe the gear ratio.

Is the correct REVERSE range ratio shown?

4.49:1

Go to Step 5

Go to Diagnos-

tic Aids

5

1.

Turn the ignition ON.

2.

Start the engine and run at idle.

3.

Using the scan tool, monitor engine, turbine, and output
speed readings in REVERSE range with the vehicle brakes
applied.

Is speed sensor data erratic?

Go to the appro-

priate speed sen-

sor DTC

Go to Step 6

6

NOTE: Do not perform a full RPM stall test in reverse range, or
vehicle damage may occur.

1.

Apply vehicle brakes and select REVERSE.

2.

With the engine at idle and REVERSE range attained, tur-
bine speed should go to zero.

3.

Using the scan tool, monitor turbine speed while increasing
engine speed to 1,000 RPM.

Did turbine speed remain at zero?

Go to Diagnos-

tic Aids

Go to Step 7

7

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 8

Go to Step 9

8

Remove the transmission for overhaul or replacement.

Did you complete the replacement?

Go to Step 11

9

Inspect for a stuck or sticking trim valve.

Did you find and correct a condition?

Go to Step 11

Go to Step 10

10

Replace pressure control (PC) solenoid B.

Did you complete the replacement?

Go to Step 11

Step

Action

Value(s)

Yes

No

_____________________________________________

On-Board Diagnostics OBD-279

5745804

11

Perform the following procedure in order to verify the repair:

1.

Clear the DTC.

2.

Start the engine.

3.

Using the scan tool, monitor REVERSE gear ratio and oper-
ate the vehicle under normal operating conditions.

4.

Select Specific DTC.

5.

Enter DTC P0736.

Has test run and passed?

System OK

Go to Step 1

Step

Action

Value(s)

Yes

No