Hummer H1 (2006+). Manual — part 146

OBD-428

On-Board Diagnostics

_____________________________________________

2

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.

Does the DTC fail this ignition?

Go to Step 4

Go to Step 3

3

1.

Select the DTC option on the scan tool.

2.

Lightly touch and move the related accelerator pedal position
(APP) sensor wiring harnesses and connectors while moni-
toring the DTC information.

Did this DTC fail this ignition during the above test?

Go to Step 4

Go to Intermit-

tent Conditions

4

1.

Turn OFF the ignition.

2.

Disconnect the APP sensor harness connector.

3.

Turn ON the ignition.

4.

Test for voltage at the APP sensor 2 5-volt reference circuit
with a test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 14

5

Connect a test lamp between the APP sensor 2 5-volt reference
circuit 720 (TN) and the APP sensor 2 low reference circuit 722
(PP).

Does the test lamp illuminate?

Go to Step 6

Go to Step 15

6

1.

Disconnect the test lamp.

2.

With the APP sensor harness connector still disconnected,
observe the APP sensor 1 voltage parameter with a scan tool.

Is the APP sensor 1 voltage less than the specified value?

1 Volt

Go to Step 13

Go to Step 7

7

Is the APP sensor 2 voltage more than the specified value?

4 Volts

Go to Step 8

Go to Step 9

8

Test the APP sensor 1 signal circuit 718 (DB) for a short to the
APP sensor 3 signal circuit 724 (DG) with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 10

9

Test the APP sensor 1 signal circuit 718 (DB) for a short to the
APP sensor 2 signal circuit 721 (LB) with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 10

10

1.

Turn OFF the ignition.

2.

Disconnect the APP sensor harness connector.

3.

Turn ON the ignition.

4.

Test for voltage at the APP sensor 1 5-volt reference circuit
717 (TN) with a test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 16

11

Connect the test lamp between the APP sensor 1 5-volt reference
circuit 717 (TN) and the APP sensor 1 low reference circuit 719
(BR).

Does the test lamp illuminate?

Go to Step 12

Go to Step 17

Step

Action

Value(s)

Yes

No

_____________________________________________

On-Board Diagnostics OBD-429

5745804

12

1.

Connect a fused jumper wire between the APP sensor 1 sig-
nal circuit 718 (DB) and the APP sensor 1 5-volt reference
circuit 717 (TN).

2.

Observe the APP sensor 1 voltage parameter with a scan
tool.

Does the scan tool indicate voltage at the specified value?

5 Volts

Go to Step 18

Go to Step 13

13

1.

Turn OFF the ignition.

2.

Disconnect C76 that contains the APP sensor 1 signal circuit
718 (DB).

3.

Test the APP sensor 1 signal circuit 718 (DB) for high resis-
tance with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

14

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector that contains the
APP sensor 2 5-volt reference circuit.

3.

Test the APP sensor 2 5-volt reference circuit for high resis-
tance with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

15

1.

Turn OFF the ignition.

2.

Disconnect C76 that contains the APP sensor 2 low reference
circuit 722 (PP).

3.

Test the APP sensor 2 low reference circuit 722 (PP) for high
resistance with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

16

1.Turn OFF the ignition.

4.

Disconnect C75 that contains the APP sensor 1 5-volt refer-
ence circuit 717 (TN).

5.

Turn ON the ignition.

6.

Test the APP sensor 1 5-volt reference circuit 717 (TN) for
high resistance with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

17

1.

Turn OFF the ignition.

2.

Disconnect C76 that contains the APP sensor 1 low reference
circuit 719 (BR).

3.

Test the APP sensor 1 low reference circuit 719 (BR) for
resistance with a DVOM.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

18

Inspect for poor connections at the harness connector of the APP
sensor.

Did you find and correct the condition?

Go to Step 22

Go to Step 19

19

Replace the faulty APP sensor assembly.

Did you complete the replacement?

Go to Step 22

20

Inspect for poor connections at the harness connector of the
ECM.

Did you find and correct the condition?

Go to Step 22

Go to Step 21

Step

Action

Value(s)

Yes

No

OBD-430

On-Board Diagnostics

_____________________________________________

21

Replace the faulty ECM.

Did you complete the replacement?

Go to Step 22

22

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 23

23

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

6-1-05

_____________________________________________

On-Board Diagnostics OBD-431

5745804

DTC P2139 Accelerator Pedal Position (APP) Sensor 1-3 Correlation (Figure OBD-112)

Figure OBD-112: Accelerator Pedal Position (APP) Circuit

Circuit Description

The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 indi-
vidual sensors within one housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface
the APP sensor with the engine control module (ECM). Each sensor has a unique functionality to determine the pedal position as
shown in the table below. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the
person driving the vehicle via the fuel injector control. If the ECM determines an out of range condition with the APP sensor 1 and
APP sensor 3, DTC P2139 sets.