Hummer H1 (2006+). Manual — part 147

OBD-432

On-Board Diagnostics

_____________________________________________

Conditions for Setting the DTC

• The APP sensor 2 and the APP sensor 3 are more than 10 percent out of range of each other.

• The above condition is present for less than one second.

Action Taken When the DTC Sets

• 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.

• If one or more APP sensor DTCs are set for a single APP sensor, the following occurs:

• The control module will not command Reduced Engine Power mode.

• The control module will use the remaining two APP sensors to calculate throttle response.

• If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs:

• The control module commands Reduced Engine Power mode.

• The APP indicated angle is limited to a predetermined value to limit the amount of throttle control.

• The message center displays Reduced Engine Power.

• If all three APP sensors are out of range, the following occurs:

• The control module commands Reduced Engine Power mode.

• The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle.

• The message center displays Reduced Engine Power.

Conditions for Clearing the DTC

• 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 non-emission re-

lated diagnostic.

• Clear the DTC with a scan tool.

APP

Sensor

ActualPedal

Position

% Depressed as Observed

on a Scan Tool

Voltage as Observed on a

Scan Tool

1

Pedal at rest

0

.52 - .80

1

Pedal at full travel

100

2.12 - 2.78

2

Pedal at rest

0

4.25 - 4.53

2

Pedal at full travel

100

2.24 - 2.93

3

Pedal at rest

0

3.95 - 4.13

3

Pedal at full travel

100

2.69 - 3.16

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-433

5745804

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 using the scan tool.

2.

Lightly touch and move the related accelerator pedal position
(APP) wiring harnesses and connectors while monitoring the
DTC information.

Did this DTC fail this ignition during the above test?

Go to Step 4

Go to Intermit-

tent Conditions

4

Is DTC P2138 also set?

Go to DTC

P2138

Go to Step 5

5

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 3, 5-volt reference circuit
723 (YL) with a test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 10

6

Connect a test lamp between the APP sensor 3, 5-volt reference
circuit 723 (YL) and the APP sensor 3 low reference circuit 725
(GY).

Does the test lamp illuminate?

Go to Step 7

Go to Step 12

7

1.

Disconnect the test lamp.

2.

With the APP sensor harness connector still disconnected,
observe the APP sensor 1 and the APP sensor 3 voltage
parameters with a scan tool.

Are both APP sensor 2 and 3 voltages above the specified value?

4 Volts

Go to Step 8

Go to Step 15

8

1.

Probe the APP sensor 1 signal circuit 718 (DB) with a test
lamp connected to ground.

2.

Observe the APP sensor 1 and the APP sensor 3 voltage
parameters with a scan tool.

Are both APP sensor 1 and 3 voltages below the specified value?

1 Volt

Go to Step 9

Go to Step 11

9

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 17

Go to Step 15

10

1.

Turn OFF the ignition.

2.

Disconnect C75 that contains the APP sensor 3, 5-volt refer-
ence circuit 723 (YL).

3.

Test the APP sensor 3, 5-volt reference circuit 723 (YL) for
high resistance with a DVOM.

Did you find and correct the condition?

Go to Step 17

Go to Step 15

Step

Action

Value(s)

Yes

No

OBD-434

On-Board Diagnostics

_____________________________________________

11

1.

Turn OFF the ignition.

2.

Disconnect C76 that contains the APP sensor 3 signal circuit
724 (DG).

3.

Turn ON the ignition.

4.

Test the APP sensor 3 signal circuit 724 (DG) for high resis-
tance with a DVOM.

Did you find and correct the condition?

Go to Step 17

Go to Step 13

12

1.

Turn OFF the ignition.

2.

Disconnect C76 that contains the APP sensor 3 low reference
circuit 725 (GY).

3.

Test the APP sensor 3 low reference circuit 725 (GY) for
high resistance with a DVOM.

4.

Did you find and correct the condition?

Go to Step 17

Go to Step 15

13

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

Did you find and correct the condition?

Go to Step 17

Go to Step 14

14

Replace the APP sensor assembly.

Did you complete the replacement?

Go to Step 17

15

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

Did you find and correct the condition?

Go to Step 17

Go to Step 16

16

Replace the faulty ECM.

Did you complete the replacement?

Go to Step 17

17

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 18

18

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

_____________________________________________

On-Board Diagnostics OBD-435

5745804

DTC P2140 Accelerator Pedal Position (APP) Sensor 2-3 Correlation

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 2 and
APP sensor 3, DTC P2140 sets.

Conditions for Setting the DTC

• The APP sensor 1 and the APP sensor 3 are more than 10 percent out of range of each other.

• The above condition is present for less than one second.

Action Taken When the DTC Sets

• 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.

• If one or more APP sensor DTCs are set for a single APP sensor, the following occurs:

• The control module will not command Reduced Engine Power mode.

• The control module will use the remaining two APP sensors to calculate throttle response.

• If certain multiple APP sensor DTCs are set for more than one APP sensor, the following occurs:

• The control module commands Reduced Engine Power mode.

• The APP indicated angle is limited to a predetermined value to limit the amount of throttle control.

• The message center displays Reduced Engine Power.

• If all three APP sensors are out of range, the following occurs:

• The control module commands Reduced Engine Power mode.

• The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle.

• The message center displays Reduced Engine Power.

Conditions for Clearing the DTC

• 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 non-emission re-

lated diagnostic.

• Clear the DTC with a scan tool.

APP

Sensor

ActualPedal

Position

% Depressed as Observed

on a Scan Tool

Voltage as Observed on a

Scan Tool

1

Pedal at rest

0

.52 - .80

1

Pedal at full travel

100

2.12 - 2.78

2

Pedal at rest

0

4.25 - 4.53

2

Pedal at full travel

100

2.24 - 2.93

3

Pedal at rest

0

3.95 - 4.13

3

Pedal at full travel

100

2.69 - 3.16