Hummer H2. Manual — part 229

Diagnostic Aids

Ensure that the resume/accel switch is not stuck or sticking in the engaged position.

For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring
Systems.

Test Description

The number below refers to the step number on the diagnostic table.

2: This step determines if condition is present.

DTC P0567

Step

Action

Yes

No

Schematic Reference :Cruise Control Schematics
Connector End View Reference:Cruise Control Connector End Views , Powertrain Control
Module (PCM) Connector End Views in Engine Controls - 4.8L, 5.3L, and 6.0L

1

Did you perform the Cruise Control Diagnostic System Check?

Go to

Step 2

Go to Diagnostic

System Check -

Cruise Control

2

1. Install a scan tool.

2. Turn the ignition ON, with the engine OFF.

3. Turn the cruise On/Off control switch ON.

4. With the scan tool, observe the Cruise Resume/Accel. Switch

parameter in the PCM data list.

Does the Cruise Resume/Accel. Switch parameter display On?

Go to

Step 3

Go to Diagnostic

Aids

3

1. Turn the ignition OFF.

2. Disconnect the cruise control switch.

3. Turn the ignition ON, with the engine OFF.

4. With the scan tool, observe the Cruise Resume/Accel. Switch

parameter.

Does the Cruise Resume/Accel. Switch parameter display On?

Go to

Step 4

Go to Step 5

4

Test the cruise control resume/accel switch signal circuit for a short
to voltage. Refer to Circuit Testing and to Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

Go to

Step 9

Go to Step 6

5

Inspect for poor connections at the harness connector of the cruise
control switch. Refer to Testing for Intermittent Conditions and
Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to

Step 9

Go to Step 8

Inspect for poor connections at the harness connector of the TAC

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Cruise Control - Hummer H2

DTC P0568

Circuit Description

The cruise control set/coast switch is an input to the throttle actuator control (TAC) module. The TAC module
uses the cruise control set/coast switch signal circuit in order to detect when the driver has requested to set the
vehicle speed or to decelerate the vehicle speed. The TAC module detects a voltage signal on the cruise control
set/coast switch signal circuit when the switch is applied. The TAC module sends a serial data signal to the
PCM via the UART serial data circuit. This DTC sets if the PCM receives a serial data signal from the TAC
module indicating that voltage is present on the cruise control set/coast switch signal circuit for longer than 90
seconds.

Conditions for Running the DTC

z

The ignition is ON.

z

The cruise control switch is ON.

Conditions for Setting the DTC

The PCM receives a serial data signal from the TAC module indicating that the set/coast switch is ON for
longer than 90 seconds.

Action Taken When the DTC Sets

z

The PCM stores the DTC information into memory when the diagnostic runs and fails.

z

The malfunction indicator lamp (MIL) will not illuminate.

z

The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this
information in the Failure Records.

z

The cruise control system is disabled.

6

module. Refer to Testing for Intermittent Conditions and Poor
Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to

Step 9

Go to Step 7

7

Replace the TAC module. Refer to Throttle Actuator Control
(TAC) Module Replacement in Engine Controls - 4.8L, 5.3L, and
6.0L.
Did you complete the replacement?

Go to

Step 9

-

8

Replace the cruise control switch. Refer to Multifunction, Turn
Signal Switch Replacement in Steering Wheel and Column.
Did you complete the replacement?

Go to

Step 9

-

9

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for Running the

DTC.

Does the DTC reset?

Go to

Step 2

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Cruise Control - Hummer H2

Conditions for Clearing the MIL/DTC

z

A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.

z

A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other
emission related diagnostic.

z

Use a scan tool in order to clear the MIL/DTC.

Diagnostic Aids

Ensure that the set/coast switch is not stuck or sticking in the engaged position.

For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring
Systems.

Test Description

The number below refers to the step number on the diagnostic table.

2: This step determines if condition is present.

DTC P0568

Step

Action

Yes

No

Schematic Reference :Cruise Control Schematics
Connector End View Reference:Cruise Control Connector End Views , Powertrain Control
Module (PCM) Connector End Views in Engine Controls - 4.8L, 5.3L, and 6.0L

1

Did you perform the Cruise Control Diagnostic System Check?

Go to

Step 2

Go to Diagnostic

System Check -

Cruise Control

2

1. Install a scan tool.

2. Turn the ignition ON, with the engine OFF.

3. Turn the cruise On/Off control switch ON.

4. With the scan tool, observe the Cruise Set/Coast Switch

parameter in the PCM data list.

Does the Cruise Set/Coast Switch parameter display On?

Go to

Step 3 Go to Diagnostic Aids

3

1. Turn the ignition OFF.

2. Disconnect the cruise control switch.

3. Turn the ignition ON, with the engine OFF.

4. With the scan tool, observe the Cruise Set/Coast Switch

parameter in the PCM data list.

Does the Cruise Set/Coast Switch parameter display On?

Go to

Step 4

Go to Step 5

Test the cruise control set/coast switch signal circuit for a short to

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Cruise Control - Hummer H2

DTC P1574

Circuit Description

This diagnostic test functions on the assumption that a sudden decrease in vehicle speed is caused by a brake
pedal application. When the PCM detects that there is a 4.2 km/h (2.6 mph) or greater decrease in vehicle speed
within 0.25 seconds and a transition of the TCC brake switch without a transition of the stop lamp switch, the
PCM sets DTC P1574.

Conditions for Running the DTC

z

DTCs P0502, P0503, P0719, and P0724 are not set.

z

The engine speed is greater than 700 RPM.

z

The traction control system or the anti-lock brake system are not active and have not failed.

z

The vehicle speed is greater than 48 km/h (30 mph) in order to enable the diagnostic.

z

The diagnostic will disable when the wheel speed is less than 16 km/h (10 mph).

Conditions for Setting the DTC

z

The vehicle speed decreases by at least 4.2 km/h (2.6 mph) within 0.25 seconds.

4

voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to

Step 9

Go to Step 6

5

Inspect for poor connections at the harness connector of the cruise
control switch. Refer to Testing for Intermittent Conditions and
Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to

Step 9

Go to Step 8

6

Inspect for poor connections at the harness connector of the TAC
module. Refer to Testing for Intermittent Conditions and Poor
Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to

Step 9

Go to Step 7

7

Replace the TAC module. Refer to Throttle Actuator Control
(TAC) Module Replacement in Engine Controls - 4.8L, 5.3L, and
6.0L.
Did you complete the replacement?

Go to

Step 9

-

8

Replace the cruise control switch. Refer to Multifunction, Turn
Signal Switch Replacement in Steering Wheel and Column.
Did you complete the replacement?

Go to

Step 9

-

9

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for Running the

DTC.

Does the DTC reset?

Go to

Step 2

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Cruise Control - Hummer H2