Hummer H1 (2006+). Manual — part 151

OBD-448

On-Board Diagnostics

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DTC P2229 Barometric Pressure (BARO) Sensor Circuit High Voltage (Figure OBD-115)

Figure OBD-115: Barometric Pressure (BARO) Sensor Circuit

Circuit Description

The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather
conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and
weather conditions. The sensor translates this action into electrical resistance. The BARO sensor wiring includes 3 circuits. The en-
gine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on
a low reference circuit. The BARO sensor provides a signal voltage to the ECM, relative to the pressure changes on the BARO sen-
sor signal circuit. The ECM converts the signal voltage input to a pressure value.

Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56
kPa at an altitude of 4 267 meters (14,000 feet), to 105 kPa at or below sea level. The BARO sensor has a range of 8-207 kPa. The
ECM uses the BARO sensor input for fuel delivery and other diagnostics.

The ECM monitors the BARO sensor signal for pressure outside of the normal range. If the ECM detects a BARO sensor pressure
that is excessively high, DTC P2229 sets.

Conditions for Setting the DTC

The BARO is more than 110 kPa for 10 seconds.

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.

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On-Board Diagnostics OBD-449

5745804

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

2

1.

Turn ON the ignition, with the engine OFF.

2.

Observe the BARO sensor pressure with a scan tool.

Does the scan tool indicate that the pressure is more than the
specified value?

110 kPa

Go to Step 4

Go to Step 3

3

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 4

Go to Intermit-

tent Conditions

4

Monitor the Diagnostic Trouble Code (DTC) Information with a
scan tool.

Does the scan tool indicate that DTC P0653 is also set?

Go to Step 7

Go to Step 5

5

1.

Turn OFF the ignition.

2.

Disconnect the electrical connector of the barometric pres-
sure (BARO) sensor.

3.

Turn ON the ignition, with the engine OFF.

Does the scan tool indicate that the BARO parameter is less than
the specified value?

11 kPa

Go to Step 6

Go to Step 8

6

1.

Connect a jumper wire between each of the terminals in the
BARO sensor harness connector and the corresponding ter-
minal at the BARO sensor.

2.

Measure the voltage from the low reference circuit 255 (OR/
BK) of the BARO sensor at the jumper wire terminal to a
good ground with a DVOM.

Is the voltage more than the specified value?

0.2 V

Go to Step 9

Go to Step 10

7

1.

Turn OFF the ignition.

2.

Disconnect the electrical connector of the BARO sensor.

3.

Turn ON the ignition, with the engine OFF.

Does the scan tool indicate that the BARO sensor pressure is less
than the specified value?

11 kPa

Go to DTC

P0653

Go to Step 8

OBD-450

On-Board Diagnostics

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8

Test the signal circuit 613 (GY/BK) of the BARO sensor for a
short to voltage.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

9

Test the low reference circuit 255 (OR/BK) of the BARO sensor
for high resistance or an open.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

10

Inspect for poor connections at the BARO sensor.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

11

Inspect for poor connections at the engine control module
(ECM).

Did you find and correct the condition?

Go to Step 14

Go to Step 13

12

Replace the faulty BARO sensor.

Did you complete the replacement?

Go to Step 14

13

Replace the faulty ECM.

Did you complete the replacement?

Go to Step 14

14

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 15

15

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

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On-Board Diagnostics OBD-451

5745804

DTC P2563 Turbocharger Boost Control Position Sensor Performance (Figure OBD-116)

Figure OBD-116: Turbocharger Boost Control Position Sensor

Circuit Description

The position of the turbocharger vanes is controlled by the engine control module (ECM). The ECM utilizes a turbocharger vane
control solenoid valve and a turbocharger vane position sensor to control the turbocharger vanes. When the engine is not under
load, the turbocharger vanes are in an open position, or no boost condition. When the engine is under load, the ECM commands the
control solenoid valve to close the turbocharger vanes, thus increasing the boost. The ECM will vary the boost dependant upon the
load requirements of the engine. The vane position sensor uses the following 3 circuits:

• A 5-volt reference circuit

• A low reference circuit

• A signal circuit

The ECM provides the sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Movement of
the sensor from the closed position to the open position provides the ECM with a signal voltage through the position sensor signal
circuit. If the ECM detects that the commanded position does not meet the actual position, DTC P2563 will set.

Conditions for Setting the DTC

• The ECM detects that the commanded vane position does not match the actual position.

• The above condition exists for more than 12 seconds.

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-