Hummer H1 (2002+). Manual - part 291

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PCM/Tech 1 Scan Tool 97

®

05745159

16

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 17.

—

17

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 18.

Go to Step 2.

18

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.

DTC P0571 - Cruise Brake Switch Circuit

Step

Action

Value(s)

Yes

No

98

PCM/Tech 1 Scan Tool

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DTC P0601 - PCM Memory Check

Step

Action

Value(s)

Yes

No

1

Important:

 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” performed?

—

Go to Step 2.

Go to OBD 

System Check.

2

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 3.

—

3

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 4.

Go to Step 2.

4

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.

DTC P0602 - PCM Programming

Step

Action

Value(s)

Yes

No

1

Important:

 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” performed?

—

Go to Step 2.

Go to OBD 

System Check.

2

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 3.

—

3

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 4.

Go to Step 2.

4

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.

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PCM/Tech 1 Scan Tool 99

®

05745159

DTC P0606 - PCM Internal Communication Interrupted

Step

Action

Value(s)

Yes

No

1

Important:

 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” performed?

—

Go to Step 2.

Go to OBD 

System Check.

2

Is DTC P0370 set?

—

Refer to the 

applicable 

DTC table

Go to Step 3.

3

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 4.

—

4

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 5.

Go to Step 2.

5

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.

100

PCM/Tech 1 Scan Tool

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®

DTC P1125 Accelerator Pedal Position (APP) 
System

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

PCM has recognized an intermittent APP fault and there are no
current APP faults stored.

Action Taken When the DTC Sets

Vehicle will operate at limited power.

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 DTC P1125 will set along with multiple APP DTCs. All
other DTCs should be diagnosed first.

Test Description

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

1.

This step determines if DTC P1125 is a hard failure or an
intermittent condition.

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