GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Equinox 🢒 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 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 Wiring Systems.
    • With a scan tool, observe the cruise control function switch parameters, in the powertrain control module (PCM) Cruise Control Data list, while rotating the steering wheel to both steering stops and individually activating each cruise control function switch separately. This will help eliminate the possibility of an internally 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. This step tests the vehicle speed signal circuit for a short to ground, for a short to voltage, for an open, or for a high resistance between the PCM and the TAC module.

    2.

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

    3.

  3. This step tests the cruise control set/coast and resume/accelerate switch signal circuit for a short to voltage.

    4.

  4. This step tests the cruise control set/coast and resume/accelerate switch signal circuit for a short to ground, for a short to voltage, for an open, or for a high resistance.

    5.

  5. DTCs will set in the powertrain control module (PCM) when you perform this diagnostic table.

Step

Action

Values

Yes

No

Schematic Reference: Cruise Control Schematics or Engine Controls 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
  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 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 9

Go to Step 3

3
  1. With the scan tool, observe the Cruise On/Off Switch parameter.
  2. Turn the cruise control On/Off switch ON.

Does the Cruise On/Off Switch parameter display On?

--

Go to Step 4

Go to Step 8

4
  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 5

Go to Step 10

5
  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 6

Go to Step 10

6

  1. Turn OFF the ignition.
  2. Disconnect the throttle actuator control (TAC) module.
  3. Turn ON the ignition, with the engine OFF.
  4. With a DMM, measure the voltage of the vehicle speed signal circuit.

Does the voltage measure greater than the specified value?

8.5 V

Go to Step 7

Go to Step 11

7

Test the vehicle speed 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 26

Go to Step 21

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 C277.
  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

9

Important: The cruise control On/Off switch must be turned ON in order to correctly view the 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 C277.
  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.
  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

Go to Step 12

Go to Step 17

10

Important: The cruise control On/Off switch must be turned ON in order to correctly view the 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 C277.
  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.
  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

Go to Step 13

Go to Step 14

11

Test the vehicle speed signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 26

Go to Step 20

12

Test the cruise control set/coast and resume/accel switch signal circuit for a short to voltage between C277 and the powertrain control module (PCM). Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 26

Go to Step 20

13

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

    • Open
    • Short to ground
    • Short to voltage
    • High resistance

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 26

Go to Step 20

14

Test the ignition 1 voltage circuit between C277 and the cruise control switch for the following:

    • Open
    • Short to ground
    • High resistance

Refer to Circuit Testing and to 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 the following:

    • Open
    • Short to ground
    • Short to voltage
    • High resistance

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 26

Go to Step 16

16

Test the cruise control set/coast and resume/accelerate switch signal circuit between C277 and the cruise control switch for the following:

    • Open
    • Short to ground
    • Short to voltage
    • High resistance

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 26

Go to Step 19

17

Test the cruise control on 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 26

Go to Step 18

18

Test the cruise control set/coast and resume/accelerate switch signal circuit between C277 and the cruise control switch 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 26

Go to Step 19

19

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 26

Go to Step 23

20

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

Go to Step 25

21

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 26

Go to Step 24

22

Repair the following in the ignition 1 voltage circuit:

    • Open
    • Short to ground
    • High resistance

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 26

--

23

Replace the cruise control switch. Refer to Steering Wheel Control Switch Assembly 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