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

Cruise Control Inoperative/Malfunctioning 2.8L and 3.6L

Diagnostic Aids

Perform the following in order 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 Lighting Systems.
    • 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.

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Engine Control Module Connector End Views in Engine Controls - 2.8L or Engine Control Module Connector End Views in Engine Controls - 3.6L (LY7)

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  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 following cruise control parameters in the Cruise/Traction Data list:
    5. • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch

Do any of the parameters listed above display ON?

Go to Step 5

Go to Step 3

3
  1. Turn the cruise control switch ON.
  2. With the scan tool, observe the Cruise Set/Coast Switch parameter.
  3. Press and hold the set/coast switch.

Does the Cruise Set/Coast Switch parameter display On?

Go to Step 4

Go to Step 6

4
  1. With the scan tool, observe the Cruise Resume/Accel Switch parameter.
  2. Press and hold the resume/accel switch.

Does the Cruise Resume/Accel Switch parameter display On?

Go to Diagnostic Aids

Go to Step 9

5
  1. Turn OFF the ignition.
  2. Disconnect C4 of the multifunction switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the following cruise control parameters:
    5. • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch

Do any of the parameters listed above display On?

Go to Step 7

Go to Step 9

6
  1. Turn OFF the ignition.
  2. Disconnect C4 of the multifunction switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the ignition 1 voltage circuit and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 11

7

Test the cruise control set/coast and 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 14

Go to Step 10

8

Test the cruise control set/coast and resume/accel switch signal circuit for the following conditions:

    • An open
    • A short to ground
    • A short to voltage
    • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 9

9

Inspect for poor connections at C4 the multifunction 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 14

Go to Step 12

10

Inspect for poor connections at the harness connector of the engine control module (ECM). 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 14

Go to Step 13

11

Repair an open, a short to ground, or a high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

12

Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 14

--

13

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

Did you complete the replacement?

Go to Step 14

--

14

Operate the cruise control system in order to verify the repair.

Does the cruise control system operate properly?

System OK

Go to Step 2

Cruise Control Inoperative/Malfunctioning 5.7L

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.

Diagnostic Aids

Perform the following in order to avoid a misdiagnosis:

    • Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan tool, observe the associated cruise control switch parameter in the powertrain control module (PCM) Cruise Control data list. This will help eliminate the possibility of an internally open or shorted inflatable restraint steering wheel module coil.
    • Inspect for proper operation of the brake lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems.
    • Electromagnetic interference (EMI) on the vehicle 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 12-16 volts.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the cruise control set/coast switch signal circuit for an open or for a high resistance.

    2.

  2. This step tests the cruise control resume/accel switch signal circuit for an open or for a high resistance.

    3.

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

    4.

  4. DTCs will set in the PCM when you perform this table.

Step

Action

Yes

No

Schematic Reference : Cruise Control Schematics

Connector End View Reference: Cruise Control Connector End Views , Powertrain Control Module Connector End Views or Engine Controls Connector End Views in Engine Controls - 5.7L

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  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 On/Off Switch parameter in the powertrain control module (PCM) Cruise Control data list.

Does the Cruise On/Off Switch parameter display Off?

Go to Step 4

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Disconnect C208.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, observe the Cruise On/Off Switch parameter.

Does the Cruise On/Off Switch parameter display Off?

Go to Step 20

Go to Step 11

4
  1. Turn the cruise control On/Off switch ON.
  2. With the scan tool, observe the Cruise On/Off Switch parameter.

Does the Cruise On/Off Switch parameter display On?

Go to Step 5

Go to Step 9

5
  1. With the scan tool, observe the Cruise Set/Coast Switch parameter in the PCM Cruise Control data list.
  2. Turn the cruise control On/Off switch On.
  3. Press and hold the cruise control Set/Coast button.

Does the Cruise Set/Coast Switch parameter display On?

Go to Step 6

Go to Step 7

6
  1. With the scan tool, observe the Cruise Resume/Accel. Switch parameter in the PCM Cruise Control data list.
  2. Press and hold the Resume/Accel switch.

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

Go to Diagnostic Aids

Go to Step 8

7

  1. Turn OFF the ignition.
  2. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Disconnect C208.
  4. Turn ON the ignition, with the engine OFF.
  5. Connect a 3-ampere fused jumper between the cruise control set/coast switch signal circuit and the ignition 1 voltage circuit.
  6. With the scan tool, observe the Cruise Set/Coast Switch parameter.

Does the Cruise Set/Coast Switch parameter display On?

Go to Step 20

Go to Step 17

8

  1. Turn OFF the ignition.
  2. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Disconnect C208.
  4. Turn ON the ignition, with the engine OFF.
  5. Connect a 3-ampere fused jumper between the cruise control resume/accel switch signal circuit and the ignition 3 voltage circuit.
  6. With the scan tool, observe the Cruise Resume/Accel. Switch parameter.

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

Go to Step 20

Go to Step 18

9

  1. Turn OFF the ignition.
  2. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
  3. Disconnect C208.
  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 10

Go to Step 13

10
  1. Connect a 3-ampere fused jumper between the ignition 1 voltage circuit and the cruise control on switch signal circuit.
  2. With the scan tool, observe the Cruise On/Off Switch parameter.

Does the Cruise On/Off Switch parameter display On?

Go to Step 20

Go to Step 16

11

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 26

Go to Step 12

12
  1. Turn OFF the ignition.
  2. Disconnect C1 of the throttle actuator control (TAC) module.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Cruise On/Off Switch parameter.

Does the Cruise On/Off Switch parameter display On?

Go to Step 22

Go to Step 21

13

Test the cruise control set/coast switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 14

14

Test the cruise control resume/accel switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 15

15

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

Did you find and correct the condition?

Go to Step 26

Go to Step 19

16

Test the cruise control on switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 21

17

Test the cruise control set/coast switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 21

18

Test the cruise control resume/accel switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 21

19

Repair the open, the high resistance, or the short to ground in the ignition 1 voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

20

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 26

Go to Step 23

21

Inspect for poor connections at the harness connector of the TAC module. 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 26

Go to Step 24

22

Inspect for poor connections at the harness connector of the PCM. 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 26

Go to Step 25

23

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 26

--

24

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

Did you complete the replacement?

Go to Step 26

--

25

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

Did you complete the replacement?

Go to Step 26

--

26

  1. Install the inflatable restraint 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 PCM DTCs.
  4. Operate the vehicle within the conditions for cruise control operation.

Does the cruise control system operate properly?

System OK

Go to Step 2