Hummer H1 (2006+). Manual - part 149

OBD-440

On-Board Diagnostics

_____________________________________________

Action Taken When the DTC Sets - Federal 

• 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 (DIC), if equipped, may display a message. 

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. 

ALTITUDE MEASURED 

IN METERS (M)

ALTITUDE MEASURED 

IN FEET (FT)

BAROMETRIC PRESSURE 

MEASURED IN KILOPASCALS (KPA)

4 267

14,000

56-64

3 962

13,000

58-66

3 658

12,000

61-69

3 353

11,000

64-72

3 048

10,000

66-74

2 743

9,000

69-77

2 438

8,000

71-79

2 134

7,000

74-82

1 829

6,000

77-85

1 524

5,000

80-88

1 219

4,000

83-91

914

3,000

87-95

610

2,000

90-98

305

1,000

94-102

0

0 Sea Level

96-104

-305

-1,000

101-105

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

_____________________________________________

 On-Board Diagnostics  OBD-441

5745804

    2

1.

Turn ON the ignition, with the engine OFF.

2.

Observe the BARO parameter with a scan tool.

3.

Compare the barometric pressure (BARO) value to the range 
specified in the altitude vs. barometric pressure table. 

Is the BARO parameter within the range specified in the altitude
vs. barometric pressure table?

Go to Step 3

Go to Step 7

    3

1.

Observe the Boost Pressure Sensor parameter with a scan 
tool.

2.

Compare the Boost Pressure Sensor value to the range speci-
fied in the altitude vs. barometric pressure table. 

Is the Boost Pressure Sensor parameter within the range specified
in the altitude vs. barometric pressure table?

Go to Step 4 

Go to Step 13 

    4

1.

Connect a J 23738-A Mityvac to the BARO sensor port.

2.

Observe the BARO parameter with a scan tool.

3.

Apply vacuum with the J 23738-A until 10 inches Hg is 
reached.

Does the BARO parameter decrease?

Go to Step 5 

Go to Step 24

    5

1.

Start the engine.

2.

Operate the vehicle, at a consistent altitude, within the Con-
ditions for Running the DTC.

3.

Observe the BARO parameter with a scan tool. 

Does the BARO parameter change more than the specified value?

15 kPa

Go to Step 7

Go to Step 6

    6

1.

Operate the vehicle, at a consistent altitude, within the Con-
ditions for Running the DTC.

2.

Observe the Boost Pressure Sensor parameter and the BARO 
parameter with a scan tool. 

Is the difference between the Boost Pressure Sensor parameter
and the BARO parameter more than the specified value?

15 kPa

Go to Step 13

Go to Intermit-

tent Conditions 

    7

Test for an intermittent and for a poor connection at the BARO
sensor connector. 

Did you find and correct the condition?

Go to Step 27 

Go to Step 8

    8

1.

Disconnect the BARO sensor.

2.

Measure the amperage between the 5-volt reference circuit 
612 (WH/BK) and the low reference circuit 255 (OR/BK), at 
the BARO sensor connector, with a DVOM.

Is the amperage more than the specified value?

170 mA

Go to Step 9 

Go to Step 10

    9

1.

Connect a jumper wire between the 5-volt reference circuit 
612 (WH/BK) and the BARO sensor signal circuit 613 (GY/
BK) at the BARO sensor connector.

2.

Observe the BARO parameter with a scan tool.

Is the pressure more than the specified value?

205 kPa

Go to Step 24 

Go to Step 19

    10

Test for an intermittent and for a poor connection at the engine
control module (ECM). 

Did you find and correct the condition?

Go to Step 27 

Go to Step 11

Step

Action

Value(s)

Yes

No

OBD-442

On-Board Diagnostics

_____________________________________________

    11

1.

Disconnect the ECM.

2.

Measure the resistance of the 5-volt reference circuit 612 
(WH/BK) between the BARO sensor connector and C75 pin 
31 of the ECM, with a DVOM.

Is the resistance more than the specified value?

5 ohms

Go to Step 23

Go to Step 12

    12

Measure the resistance of the low reference circuit 255 (OR/BK)
between the BARO sensor connector and C75 pin 7 of the ECM,
with a DVOM.

Is the resistance more than the specified value?

5 ohms

Go to Step 23 

Go to Step 26

    13

Test for an intermittent and for a poor connection at the boost
pressure sensor connector. 

Did you find and correct the condition?

Go to Step 27

Go to Step 14

    14

1.

Disconnect the boost pressure sensor.

2.

Measure the amperage between the 5-volt reference circuit 
612 (WH/BK) and the low reference circuit 255 (OR/BK), at 
the boost pressure sensor connector, with a DVOM.

Is the amperage more than the specified value?

170 mA

Go to Step 15 

Go to Step 16

    15

1.

Connect a jumper wire between the 5-volt reference circuit 
612 (WH/BK) and the signal circuit 613 (GY/BK) of the 
boost pressure sensor at the connector.

2.

Observe the Boost Pressure Sensor parameter with the scan 
tool.

Is the pressure more than the specified value?

254 kPa 

(36 psi)

Go to Step 25

Go to Step 20

    16

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

Did you find and correct the condition?

Go to Step 27

Go to Step 17

    17

1.

Disconnect the ECM.

2.

Measure the resistance of the 5-volt reference circuit 612 
WH/BK) between the boost pressure sensor connector and 
C75 pin 31 of the ECM, with a DVOM.

Is the resistance more than the specified value?

5 ohms

Go to Step 23

Go to Step 18

    18

Measure the resistance of the low reference circuit 255 (OR/BK)
between the boost pressure sensor connector and C75 pin 7 of the
ECM, with a DVOM.

Is the resistance more than the specified value?

5 ohms

Go to Step 23 

Go to Step 26

    19

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

Did you find and correct the condition?

Go to Step 27

Go to Step 21

    20

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

Did you find and correct the condition?

Go to Step 27 

Go to Step 22

    21

1.

Disconnect the ECM.

2.

Measure the resistance of the BARO sensor signal circuit 
613 (GY/BK) between the BARO sensor connector and C76 
pin 46 of the ECM, with a DVOM.

Is the resistance more than the specified value?

5 ohms

Go to Step 23 

Go to Step 26

Step

Action

Value(s)

Yes

No

_____________________________________________

 On-Board Diagnostics  OBD-443

5745804

    22

1.

Disconnect the ECM.

2.

Measure the resistance of the boost pressure sensor signal 
circuit 615 (LG) between the boost pressure sensor connec-
tor pin B and C76 pin 23 of the ECM, with a DVOM.

Is the resistance more than the specified value?

5 ohms

Go to Step 23 

Go to Step 26

    23

Repair the high resistance in the circuit. 

Did you complete the repair?

Go to Step 27

    24

Replace the faulty BARO sensor. 

Did you complete the replacement?

Go to Step 27

    25

Replace the faulty boost pressure sensor.

Did you complete the replacement?

Go to Step 27

    26

Replace the faulty ECM.

Did you complete the replacement?

Go to Step 27

    27

1.

Clear the DTCs with a scan tool.

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 2 

Go to Step 28

    28

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