GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Generic 🢒 2005 🢒 Unit Repair 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Cruise Control Inoperative/Malfunctioning

Diagnostic Aids

Caution: Refer to SIR Caution in the Preface section.

Disable the inflatable restraint steering wheel module when performing this diagnostic table. Refer to SIR Disabling and Enabling in SIR.

Perform the following to avoid misdiagnosis:

    • Ensure that the following cruise control switches are not stuck in the engaged position:
       - On/off switch
       - Set/coast switch
       - Resume/accel switch
    • Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation in Wiring Systems.
    • Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan tool, observe the Cruise Control Switch parameter in the Body and Accessories, Cruise Control data list. This will help eliminate the possibility of a internally open or shorted inflatable restraint steering wheel module coil.
    • Electromagnetic interference (EMI) on the speed sensor signal circuit may cause erratic cruise control operation.
    • For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Conditions for Enabling Cruise Control
    • The vehicle speed is greater than 40 km/h (25 mph).
    • The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear.
    • The system voltage is within 9-16 volts.
    • The park brake is not applied.

Test Description

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

  1. This step tests the ignition 1 voltage circuit for an open, a short to ground, or a high resistance.

Step

Action

Values

Yes

No

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Powertrain Control Module Connector End Views in Engine Controls - 3.5L (LX9) or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Is DTC P0573 current in the powertrain control module (PCM)?

--

Go to DTC P0573 in Lighting Systems

Go to Step 3

3
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Turn the cruise control on/off switch OFF.
  4. With the scan tool, observe the Cruise Control Switch parameter in the Body and Accessories, Cruise Control data list.

Does the Cruise Control Switch parameter display Off?

--

Go to Step 4

Go to Step 7

4
  1. Turn the cruise control on/off switch ON.
  2. With the scan tool, observe the Cruise Control Switch parameter.

Does the Cruise Control Switch parameter display On?

--

Go to Step 5

Go to Step 8

5
  1. With the scan tool, observe the Cruise Control Switch parameter.
  2. Turn the cruise control on/off switch ON.
  3. Press and hold the cruise control Set/Coast button.

Does the Cruise Control Switch parameter display Set?

--

Go to Step 6

Go to Step 17

6
  1. With the scan tool, observe the Cruise Control Switch parameter.
  2. Press and hold the resume/accel switch.

Does the Cruise Control Switch parameter Display Resume?

--

Go to Diagnostic Aids

Go to Step 17

7
  1. Turn OFF the ignition.
  2. Remove the inflatable steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Disconnect C3.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, observe the Cruise Control Switch parameter.

Does the Cruise Control Switch parameter display Off?

--

Go to Step 12

Go to Step 14

8

  1. Turn OFF the ignition.
  2. Remove the inflatable steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Disconnect C3.
  4. Turn ON the ignition, with the engine OFF.
  5. Connect a test lamp between the ignition 1 voltage circuit and a good ground.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 19

9
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Cruise Control Switch parameter.

Does the Cruise Control Switch parameter display 5 volts?

--

Go to Step 11

Go to Step 10

10

Test the cruise control set/coast and resume accelerate switch signal circuit between C3 and the body control module (BCM) for the following:

    • A high resistance
    • A short to ground
    • An open

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 18

11

Test the cruise control on switch signal circuit for the following:

    • A high resistance
    • A short to ground
    • An open

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 15

12

Test the cruise control on switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 13

13

Test the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage between C3 and the cruise control switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 17

14

Test the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage between C3 and the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 18

15

Test the cruise control set/coast and resume accelerate switch signal circuit between C3 and the cruise control switch for the following:

    • A high resistance
    • A short to ground
    • An open

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 16

16

Test the ignition 1 voltage circuit between C3 and the cruise control switch for the following:

    • A high resistance
    • A short to ground
    • An open

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 17

17

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

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 BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 21

19

Repair the following in the Ignition 1 voltage circuit:

    • A high resistance
    • A short to ground
    • An open

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

20

Replace the cruise control switch. Refer to Steering Wheel Control Switch Assembly Replacement in Steering Wheel and Column.

Did you complete the replacement?

--

Go to Step 22

--

21

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 22

--

22
  1. Install the inflatable steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  2. Enable the inflatable restraint steering wheel module. Refer to SIR Disabling and Enabling in SIR.
  3. Use the scan tool in order to clear the powertrain control module (PCM) DTCs.
  4. Operate the cruise control system in order to verify the repair.

Does the cruise control system operate properly?

--

System OK

Go to Step 2