Hummer H1 (2006+). Manual - part 154

OBD-460

On-Board Diagnostics

_____________________________________________

Action Taken When the DTC Sets 

• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diag-

nostic runs and fails. 

• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the

control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecu-
tive ignition cycle, the control module records the operating conditions at the time of the failure. The control module 
writes the operating conditions to the Freeze Frame and updates the Failure Records. 

Conditions for Clearing the MIL/DTC 

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic 

runs and does not fail. 

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes. 

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related 

diagnostic.

• Clear the MIL and the DTC with a scan tool. 

Step

Action

Value(s)

Yes

No

    1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnos-

tic System 

Check - Vehicle 

    2

1.

Turn ON the ignition, with the engine OFF.

2.

Monitor the DTC Information with the scan tool.

Is DTC P0653 also set?

Go to DTC 

P0653

Go to Step 3

    3

1.

Start the engine.

2.

Select the TC Vane Position Sensor test in Scan Tool Output 
Controls.

3.

With the engine at idle, observe the TC vane position sensor 
and the desired TC vane position while commanding the TC 
vane position sensor to 100 percent with the scan tool.

Is the TC vane position at or near the desired TC vane position
while commanding the TC vane position sensor from 0-100 per-
cent?

Go to Step 4

Go to Step 5

    4

1.

Observe the Freeze Frame/Failure Records for this DTC.

2.

Turn OFF the ignition for 30 seconds.

3.

Start the engine.

4.

Operate the vehicle within the Conditions for Running the 
DTC. You may also operate the vehicle within the conditions 
that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 5

Go to Intermit-

tent Conditions 

    5

1.

Turn OFF the ignition.

2.

Disconnect the turbocharger (TC) vane position sensor.

3.

Turn ON the ignition, with the engine OFF.

4.

Measure the voltage from the signal circuit 368 (WH) pin B 
to the low reference circuit 369 (BR) pin A of the vane posi-
tion sensor connector with a DVOM.

Is the voltage less than the specified value?

4.8 Volts

Go to Step 7

Go to Step 6

    6

Is the voltage more than the specified value?

5.2 Volts

Go to Step 11

Go to Step 8

_____________________________________________

 On-Board Diagnostics  OBD-461

5745804

    7

Measure the voltage from the signal circuit 368 (WH) to a good
ground with a DVOM.

Is the voltage less than the specified value?

4.8 Volts

Go to Step 12

Go to Step 10

    8

Measure the current between the 5-volt reference circuit 367
(GY) pin C and the low reference circuit 369 (BR) pin A at the
TC vane position sensor connector, with a DVOM.

Is the current less than the specified value?

180 mA

Go to Step 9

Go to Step 13

    9

Test the vane position sensor low reference circuit 369 (BR) for
high resistance between C76 pin 44 and pin A of the vane posi-
tion sensor connector. 

Did you find and correct the condition?

Go to Step 17 

Go to Step 14

    10

Test the vane position sensor low reference circuit 369 (BR) for
an open and for a high resistance between C76 pin 44 and pin A
of the vane position sensor connector. 

Did you find and correct the condition?

Go to Step 17

Go to Step 14

    11

NOTE: Disconnecting the engine control module (ECM) may
eliminate the short during testing.

Test the vane position sensor signal circuit 368 (WH) for a short
to voltage between C76 pin 31 and pin B of the vane position sen-
sor connector. 

Did you find and correct the condition?

Go to Step 17 

Go to Step 14

    12

Test the vane position sensor signal circuit 368 (WH) for an open
and for a high resistance between C76 pin 31 and pin B of the
vane position sensor connector.. 

Did you find and correct the condition?

Go to Step 17 

Go to Step 14

    13

Test for an intermittent and for a poor connection at the vane po-
sition sensor.

Did you find and correct the condition?

Go to Step 17 

Go to Step 15

    14

Test for an intermittent and for a poor connection at the ECM. 

Did you find and correct the condition?

Go to Step 17 

Go to Step 16

    15

Replace the faulty turbocharger vane position sensor. 

Did you complete the replacement?

Go to Step 17 

    16

Replace the faulty ECM. 

Did you complete the replacement?

Go to Step 17 

    17

1.

Clear the DTCs with a scan tool.

2.

Turn OFF the ignition for 30 seconds.

3.

Start the engine.

4.

Perform the turbocharger learn procedure. Refer to Turbo-
charger Learn Procedure .

5.

Operate the vehicle within the Conditions for Running the 
DTC. You may also operate the vehicle within the conditions 
that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 18

Step

Action

Value(s)

Yes

No

OBD-462

On-Board Diagnostics

_____________________________________________

    18

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnos-

tic Trouble 

Code

System OK

Step

Action

Value(s)

Yes

No

_____________________________________________

 On-Board Diagnostics  OBD-463

5745804

DTC P2636 Fuel Transfer Pump Flow Insufficient

Circuit Description

The fuel pump is located on the left frame rail between the fuel tanks. The engine control module (ECM) provides ignition positive
voltage to the coil side of the fuel pump relay. The ECM energizes the fuel pump relay, which applies power to the fuel transfer
pump. Fuel is transferred from the rear fuel tank to the front fuel tank in order to ensure all of the usable fuel volume is available to
the engine. If the ECM commands the transfer fuel pump ON and a predetermined change in the front and rear fuel level sensors
does not occur, this DTC sets.

Conditions for Setting the DTC

The ECM detects a primary fuel level increase and a secondary fuel level decrease of less than 2.6 liters (0.70 gallons) each, within
120 seconds.

Action Taken When the DTC Sets 

• The control module stores the DTC information into memory when the diagnostic runs and fails. 

• The malfunction indicator lamp (MIL) will not illuminate. 

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this informa-

tion in the Failure Records. 

• The driver information center, if equipped, may display a message. 

• The fuel gage will be commanded to empty. 

Conditions for Clearing the DTC 

• A current DTC Last Test Failed clears when the diagnostic runs and passes. 

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission re-

lated diagnostic. 

• Clear the DTC with a scan tool. 

Diagnostic Aids 

• When outside temperatures are below 0°C (32°F), the fuel tank pickup screen may ice over from water in the fuel tank. 

• If the engine is running while fueling the vehicle, this DTC may set. 

• The fuel will default to empty when this DTC sets. 

Step

Action

Value(s)

Yes

No

    1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnos-

tic System 

Check - Vehicle 

    2

Is DTC P0461, P0462, P0463, P2067, or P2068 also set?

Go to Diagnos-

tic Trouble 

Code (DTC) 

List

Go to Step 3