Hummer H1 (2006+). Manual - part 139

 

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Hummer H1 (2006+). Manual - part 139

 

 

OBD-400

On-Board Diagnostics

_____________________________________________

Circuit Description

The fuel injector control module (FICM) activates the fuel injector. The engine control module (ECM) signals the FICM to turn
ON the injectors through the fuel injector control circuits. The FICM self monitors the supply voltage whenever the ignition is ON.

Conditions for Setting the DTC

The FICM detects low supply voltage for less than 1 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. 

• The driver information center, if equipped, may display a message. 

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. 

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 - Vehicle 

in Vehicle DTC 

Information

    2

Do any other DTCs set?

Go to Diagnos-

tic Trouble 

Code (DTC) 

List

Go to Step 3

    3

NOTE: Use connection pin adapters from J 35616-B Adapter
Kit.

1.

Turn OFF the ignition.

2.

Disconnect the fuel injection control module (FICM) con-
nectors.

3.

Turn ON the ignition.

4.

Probe the FICM power circuits with a DVOM connected to 
one of the FICM ground circuits.

Does the voltage measure more than 10 volts?

Go to Step 5 

Go to Step 4

    4

Repair high resistance in the FICM power or ground circuits.

Did you complete the repair?

Go to Step 6 

    5

Replace the faulty FICM. 

Did you complete the replacement?

Go to Step 6 

_____________________________________________

 On-Board Diagnostics  OBD-401

5745804

    6

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 7

    7

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

OBD-402

On-Board Diagnostics

_____________________________________________

DTC P2122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage (Figure OBD-105)

Figure OBD-105:   Accelerator Pedal Position (APP) Sensor 1 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 1 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 low voltage with the APP sensor 1 circuit, DTC
P2122 sets.

_____________________________________________

 On-Board Diagnostics  OBD-403

5745804

Conditions for Setting the DTC 

• The APP sensor 1 voltage is less than 0.25 volts. 

• The above condition is present for less than 1 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

 

 

 

 

 

 

 

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