GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Terraza 🢒 Accessories 🢒 Cruise Control 🢒 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 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
       - Cancel 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 associated 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.
    • 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 path.

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

Step

Action

Values

Yes

No

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Master Electrical Component List in Wiring 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 following cruise control parameters in the Body and Accessories Cruise Control data list:
    5. • Cruise On/Off Switch
    • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch

Do any of the parameters listed above display On?

--

Go to Step 13

Go to Step 4

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

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.
  2. Press and hold the Set/Coast switch.

Does the Cruise Set/Coast Switch parameter display On?

--

Go to Step 6

Go to Step 11

6
  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 Step 7

Go to Step 11

7
  1. Turn OFF the ignition.
  2. Disconnect C3 at the body control module (BCM).
  3. Turn ON the ignition, with the engine OFF.
  4. With a DMM, measure the voltage of the cruise control cancel signal circuit.

Does the voltage measure at or greater than the specified voltage?

0.5 V

Go to Step 19

Go to Step 8

8
  1. Activate and hold the cruise control cancel switch.
  2. With a DMM, measure the voltage of the cruise control cancel signal circuit.

Does the voltage measure at the specified voltage?

B+

Go to Step 12

Go to Step 20

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 C6.
  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 22

10

Important: The cruise control on/off switch must be turned ON in order to correctly view the Cancel switch, set/coast switch, and the resume/accel switch resistance values with the DMM.

  1. With a DMM, measure the resistance of the cruise control switch between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit at the cruise control switch.
  2. Individually activate and hold the cruise control function switches while measuring the resistance of the cruise control function switches.

Do the cruise control function switch resistance values measure between the specified values?

Off = O.L.

On = 7.8 K-8.6 K ohms

Resume = 2.7 K-3.0 K ohms

Set = 1.2 K-1.3 K ohms

Cancel = 0-1 K ohms

Go to Step 15

Go to Step 16

11

Important: The cruise control on/off switch must be turned ON in order to correctly view the Cancel switch, set/coast switch, and the resume/accel switch resistance values with the DMM.

  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 C6.
  4. With a DMM, measure the resistance of the cruise control switch between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit at the cruise control switch.
  5. Individually activate and hold the cruise control function switches while measuring the resistance of the cruise control function switches.

Do the cruise control function switch resistance values measure between the specified values?

Off = O.L.

On = 7.8 K-8.6 K ohms

Resume = 2.7 K-3.0 K ohms

Set = 1.2 K-1.3 K ohms

Cancel = 0-1 K ohms

Go to Step 15

Go to Step 16

12
  1. Turn OFF the ignition.
  2. Connect C3 at the BCM.
  3. Disconnect the throttle actuator control (TAC) module.
  4. Turn ON the ignition, with the engine OFF.
  5. With a DMM, measure the voltage of the stop lamp switch signal circuit.

Does the voltage measure greater than the specified value?

8.5 V

Go to Step 18

Go to Step 21

13
  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 C6.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, observe the following cruise control parameters:
    6. • Cruise On/Off Switch
    • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch

Do any of the parameters listed above display On?

--

Go to Step 14

Go to Step 16

14

Test the cruise control set/coast and resume/accel 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 17

15

Test the cruise control Set/Coast and Resume/Accel switch signal circuit for the following:

    • Short to ground
    • Open
    • 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 17

16

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

17

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

18

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

19

Repair the short to voltage in the cruise control cancel signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 26

--

20

Repair the following in the cruise control cancel signal circuit:

    • Short to ground
    • Open
    • High Resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 26

--

21

Repair the open or the high resistance in the stop lamp switch signal circuit between the underhood fuse block and the TAC module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 26

--

22

Repair the open, the short to ground, or the high resistance 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

--

23

Replace the cruise control switch. Refer to Cruise Control Switch Replacement .

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 cruise control system in order to verify the repair.

Does the cruise control system operate properly?

--

System OK

Go to Step 2