Hummer H1 (2002+). Manual - part 282

_____________________________________________________

PCM/Tech 1 Scan Tool 61

®

05745159

DTC P0226 - Accelerator Pedal Position (APP) Sensor 3 Circuit Performance

Step

Action

Value(s)

Yes

No

1

Important:

 Before clearing DTC(s) use the scan tool “Capture Info” to

record Freeze Frame and Failure Record for reference, as data will be lost
when “Clear Info” function is used.

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

—

Go to Step 2. Go to OBD Sys-

tem Check.

2

1. Ignition “ON”, engine “OFF”.
2. With the throttle closed, observe APP voltages on the scan tool.

Are APP voltages at specified values?

.45-.95v
4.0-4.5v
3.6-4.0v

Go to Step 3. Go to Step 4.

3

DTC is intermittent. If no additional DTCs are stored, refer to “Diagnostic
Aids”. If additional DTCs were stored, refer to those chart(s).

—

Go to the 

applicable 

DTC table.

Go to 

Diagnostic 

Aids.

4

1. Disconnect the APP sensor electrical connector.
2. Ignition “ON”, engine “OFF”.

3. With J–39200 connected to ground, probe APP sensor 5 volt reference

circuits at APP harness terminals “G”, “D” and “E”.

Is voltage at the specified value on all circuits?

4.75v

Go to Step 5. Go to Step 6.

5

1. Ignition “ON”, engine “OFF”.
2. With a test light connected to B+, probe APP sensor ground circuits at

the APP sensor harness terminals “A”, “B” and “J”.

Is the test light “ON” (all circuits)?

—

Go to Step 9.

Go to Step 8.

6

1. Ignition “OFF”.
2. Disconnect the PCM and check the 5 volt reference circuit for an open or

short to ground.

3. If the 5 volt reference circuit is open or shorted to ground, repair it as

necessary.

Was the 5 volt reference circuit open or shorted to ground?

—

Go to Step 11.

Go to Step 7.

7

Check the 5 volt reference circuit for a poor connection at the PCM and 
replace terminal if necessary.
Did the terminal require replacement?

—

Go to Step 11. Go to Step 10.

8

1. Ignition “OFF”.
2. Disconnect the PCM and check for an open sensor ground circuit to the

PCM.

3. If problem is found, repair as necessary.

Was APP sensor ground circuit open?

—

Go to Step 11. Go to Step 10.

9

Replace the APP module.

Is Action complete?

—

Go to Step 11.

—

10

Replace the faulty PCM. Notice: If the PCM is faulty, the new PCM must 
be programmed. Go to PCM replacement and programming procedures.
Is the action complete?

—

Go to Step 11.

—

11

1. Using the Scan Tool, select “DTC”, “Clear Info”.
2. Start engine and idle at normal operating temperature.

3. Select “DTC”, “Specific”, then enter the DTC number which was set.

4. Operate vehicle within the conditions for setting this DTC as specified in

the supporting text.

Does the Scan Tool indicate that this diagnostic Ran and Passed?

—

Go to Step 12.

Go to Step 2.

12

Using the Scan Tool, select “Capture Info”, “Review Info”.
Are any DTCs displayed that have not been diagnosed?

—

Go to the 

applicable 

DTC table

System OK

62

PCM/Tech 1 Scan Tool

_____________________________________________________

®

DTC P0227 Accelerator Pedal Position (APP) 
Sensor 3 Circuit Low Voltage

Circuit Description

The Accelerator Pedal Position (APP) module provides a volt-
age signal that changes relative to accelerator position. There
are three sensors located within the APP module that are scaled
differently. This is a type C DTC.

Conditions for Setting the DTC

• Voltage is less than .25 volts on APP 3 sensor.

• Conditions met for 2 seconds.

Action Taken When the DTC Sets

• The input from APP 3 sensor is ignored.

• A current and history DTC will set but it will not turn on 

the “Service Throttle Soon” lamp.

• The throttle will operate normally as long as there is 

only one sensor malfunction present. If two different 
APP sensors have a malfunction, the “Service Throttle 
Soon” lamp will light and the PCM will limit power. If 
three APP sensors have a malfunction present, the “Ser-
vice Throttle Soon” lamp will light and the PCM will 
only allow the engine to operate at idle.

Conditions for Clearing the MIL/DTC

• A History DTC will clear when forty consecutive 

warm-up cycles that the diagnostic does not fail (coolant 
temperature has risen 5°C (40°F) from start up coolant 
temperature and engine coolant temperature exceeds 
71°C (160°F) that same ignition cycle).

• Use of a Scan Tool

Diagnostic Aids

A scan tool reads APP 3 position in volts and should read about
4.0 volts with throttle closed and ignition “ON” or at idle. Volt-
age should decrease at a steady rate as throttle is moved toward
Wide Open Throttle (WOT). Also 90% pedal travel is accept-
able for correct APP operation. Scan APP 3 sensor while de-
pressing accelerator pedal with engine stopped and ignition
“ON”, Display should vary from about 4.0 volts when throttle
was closed to about 2.0 volts when throttle is held at Wide
Open Throttle (WOT) position. Refer to “Intermittents”, in
Section 2.

Test Description

Number(s) below refer to the circled number(s) on the diagnos-
tic table.

2. This step determines if P0227 is the result of a hard failure or

an intermittent condition.

3. This step checks the PCM and wiring.

FUSE 5C
10AMP
INTERIOR

FUSE 3A
10 AMP
EXTERIOR

ON/
OFF

SET
COAST

RESUME
ACCEL

HOT IN RUN
AND START

HOT IN RUN
AND START

A

29

42

37

C1

C29-A11

C29-B11

C27-D10

C28-D14

C28-C2

C27-D12

C27-D3

C27-D4

C27-D6

C29-B2

C29-B1

C27-C5

C29-A12

C5-D3

C5-A4

A

B

154 TN

151 GY

152 DB

153 LG

ON / OFF
SIGNAL

SET
COAST
SIGNAL

RESUME
ACCEL
SIGNAL

WASTEGATE
SOLENOID
CONTROL

5 VOLT
REFERENCE

APP 3
SIGNAL

GROUND

APP 1
SIGNAL

GROUND

GROUND

D

B

C

A

G

E

F

J

K

3

1

2

C1

22

20

14

15

60

32

53

17

44

720 TN

717 WH

723 YL

724 DG

725 GY

718 DB

719 BR

721 LB

722 PP

ACCELERATIOR
PEDAL POSITION
SENSOR

POWERTRAIN
CONTROL
MODULE
(PCM)

APP 2
SIGNAL

9-S12-055

B

C

D

295 BR

YL

GRN

RD

_____________________________________________________

PCM/Tech 1 Scan Tool 63

®

05745159

DTC P0227 - Accelerator Pedal Position (APP) Sensor 3 Circuit Low Voltage

Step

Action

Value(s)

Yes

No

1

Important:

 Before clearing DTC(s) use the scan tool “Capture Info” to record Freeze

Frame and Failure Record for reference, as data will be lost when “Clear Info” func-
tion is used.

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

—

Go to

Step 2.

Go to OBD

System 
Check.

2

1. Ignition “ON”, engine “OFF”.
2. With the throttle closed, observe APP 3 voltages on the scan tool.

Is APP 3 voltage less than or equal to the specified value?

.25v

Go to 

Step 4.

Go to

Step 3.

3

DTC is intermittent. If no additional DTCs are stored, refer to “Diagnostic Aids”. If
additional DTCs were stored, refer to those table(s) first.

Are additional DTCs stored?

—

Go to the 

applicable 

DTC table.

Go to 

Diagnostic 

Aids.

4

1. Disconnect the APP sensor electrical connector.
2. Jumper APP 3 5 volt reference circuit and the APP 3 signal together at the APP

sensor harness connector.

3. Observe the APP 3 voltage on the Scan Tool.

Is APP 3 voltage greater than the specified value?

5v

Go to

Step 5.

Go to 

Step 6.

5

1. Connect a test light between B+ and the APP 3 sensor signal circuit at the APP

sensor harness connector.

2. Observe the APP 3 voltage on the Scan Tool.

Is APP 3 voltage greater than the specified value?

5v

Go to 

Step 10.

Go to 

Step 8.

6

1. Ignition “OFF”.
2. Disconnect the PCM and check the 5 volt reference circuit for an open or short to

ground.

3. If the 5 volt reference circuit is open or shorted to ground, repair as necessary.
Was the 5 volt reference circuit open or shorted to ground?

—

Go to 

Step 13.

Go to 

Step 7.

7

Check the 5 volt reference circuit for a poor connection at the PCM and replace termi-
nal if necessary. Did the terminal require replacement?

—

Go to

Step 13.

Go to 

Step 12.

8

1. Ignition “OFF”.
2. Disconnect the PCM, and check the APP 3 signal circuit for an open, short to

ground.

3. If the APP 3 sensor signal circuit is open or shorted to ground, repair as necessary.

Was APP 3 signal circuit open or shorted to ground?

—

Go to

Step 13.

Go to

Step 9.

9

Check the APP 3 sensor signal circuit for a poor connection at the PCM and replace 
terminal if necessary.
Did the terminal require replacement?

—

Go to

Step 13.

Go to

Step 12.

10

Check for a poor electrical connection at the APP sensor. 
Was a repair performed?

—

Go to

Step 13. 

To to 

Step 12.

11

Replace the APP module.

Is Action complete?

—

Go to 

Step 13.

—

12

Replace the faulty PCM. Notice: If the PCM is faulty, the new PCM must be pro-
grammed. Go to PCM replacement and programming procedures.
Is the action complete?

—

Go to 

Step 13.

—

13

1. Using the Scan Tool, select “DTC”, “Clear Info”.
2. Start engine and idle at normal operating temperature.

3. Select “DTC”, “Specific”, then enter the DTC number which was set.

4. Operate vehicle within the conditions for setting this DTC as specified in the sup-

porting text.

Does the Scan Tool indicate that this diagnostic Ran and Passed?

—

Go to

Step 14.

Go to

Step 2.

14

Using the Scan Tool, select “Capture Info”, “Review Info”.
Are any DTCs displayed that have not been diagnosed?

—

Go to the 

applicable 

DTC table

System OK

64

PCM/Tech 1 Scan Tool

_____________________________________________________

®

DTC P0228 Accelerator Pedal Position (APP) 
Sensor 3 Circuit High Voltage

Circuit Description

The Accelerator Pedal Position (APP) module provides a volt-
age signal that changes relative to accelerator position. There
are three sensors located within the APP module that are scaled
differently. This is a type C DTC.

Conditions for Setting the DTC

• Voltage is greater than 4.75 volts on APP 3 sensor.

• Conditions met for 2 seconds.

Action Taken When the DTC Sets

• The input from APP 3 sensor is ignored.

• A current and history DTC will set but it will not turn on 

the “Service Throttle Soon” lamp. The throttle will op-
erate normally as long as there is only one malfunction 
present. If two different APP sensors have a malfunc-
tion, the “Service Throttle Soon” lamp will light and the 
PCM will limit power. If three APP sensors have a mal-
function present, the “Service Throttle Soon” lamp will 
light and the PCM will only allow the engine to operate 
at idle.

Conditions for Clearing the MIL/DTC

• A History DTC will clear when forty consecutive 

warm-up cycles that the diagnostic does not fail (coolant 
temperature has risen 5°C (40°F) from start up coolant 
temperature and engine coolant temperature exceeds 
71°C (160°F) that same ignition cycle).

• Use of a Scan Tool

Diagnostic Aids

A scan tool reads APP 3 position in volts and should read about
4.0 volts with throttle closed and ignition “ON” or at idle. Volt-
age should decrease at a steady rate as throttle is moved toward
Wide Open Throttle (WOT). Also, 90% pedal travel is accept-
able for correct APP operation. Refer to Section 2 for “Inter-
mittents”. Scan APP 3 sensor while depressing accelerator
pedal with engine stopped and ignition “ON”. Display should
vary from about 4.0 volts when throttle is closed to about 2.0
volts when throttle is held at Wide Open Throttle (WOT) posi-
tion.

Test Description

Number(s) below refer to the number(s) on the diagnostic ta-
ble.

2. This step determines if P0228 is a hard failure or an intermit-

tent condition.

3. This step checks the PCM and wiring.

FUSE 5C
10AMP
INTERIOR

FUSE 3A
10 AMP
EXTERIOR

ON/
OFF

SET
COAST

RESUME
ACCEL

HOT IN RUN
AND START

HOT IN RUN
AND START

A

29

42

37

C1

C29-A11

C29-B11

C27-D10

C28-D14

C28-C2

C27-D12

C27-D3

C27-D4

C27-D6

C29-B2

C29-B1

C27-C5

C29-A12

C5-D3

C5-A4

A

B

154 TN

151 GY

152 DB

153 LG

ON / OFF
SIGNAL

SET
COAST
SIGNAL

RESUME
ACCEL
SIGNAL

WASTEGATE
SOLENOID
CONTROL

5 VOLT
REFERENCE

APP 3
SIGNAL

GROUND

APP 1
SIGNAL

GROUND

GROUND

D

B

C

A

G

E

F

J

K

3

1

2

C1

22

20

14

15

60

32

53

17

44

720 TN

717 WH

723 YL

724 DG

725 GY

718 DB

719 BR

721 LB

722 PP

ACCELERATIOR
PEDAL POSITION
SENSOR

POWERTRAIN
CONTROL
MODULE
(PCM)

APP 2
SIGNAL

9-S12-055

B

C

D

295 BR

YL

GRN

RD