GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Corvette 🢒 Body and Accessories 🢒 Cruise Control 🢒 Cruise Control Inoperative/Malfunctioning

Diagnostic Aids

Important: Perform the following in order to avoid misdiagnosis.

   • Inspect for proper operation of brake lamps and clutch switch, if equipped.
   • Inspect for proper operation of the transmission range switch.
   • EMI on the speed sensor signal circuit may cause erratic cruise control operation.

Conditions for Enabling Cruise Control

The vehicle speed is greater than 40 km/h (25 mph).

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

1

Did you perform A Diagnostic System Check - Cruise Control?

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2
  1. Connect a scan tool.
  2. Monitor the Cruise On switch parameter in the powertrain control module (PCM) data list.
  3. Turn ON the cruise control switch.

Did the scan tool parameter change state?

Go to Step 3

Go to Step 9

3
  1. Observe the cruise control Set/Coast parameter in the PCM data list.
  2. Press the cruise control Set button.

Did the cruise control Set/Coast parameter change state?

Go to Step 4

Go to Step 14

4
  1. Observe the cruise control Resume/Accelerate parameter in the PCM data list.
  2. Press the Resume/Accelerate switch.

Did the cruise control Resume Accelerate parameter change state?

Go to Step 5

Go to Step 15

5
  1. Observe the stop lamp switch parameter in the PCM data list.
  2. Press the brake pedal.

Did the stop lamp switch parameter change state?

Go to Step 6

Go to Step 10

6
  1. Observe the TCC/Brake switch parameter in the PCM data list.
  2. Press the brake pedal.

Did the cruise release switch parameter change state?

Go to Step 7

Go to Step 

7

Is the vehicle equipped with a manual transmission?

Go to Step 8

Go to Step 29

8
  1. Observe the clutch pedal position (CPP) switch parameter in the PCM data list.
  2. Press the clutch pedal.

Did the CPP switch parameter change state?

Go to Step 29

Go to Step 12

9
  1. Turn OFF the ignition.
  2. Disconnect the multifunction turn signal lever.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the multifunction turn signal lever ignition positive voltage circuit with a test lamp connected to a good ground.

Did the test lamp illuminate?

Go to Step 13

Go to Step 21

10
  1. Turn OFF the ignition.
  2. Disconnect the stop lamp switch harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the stop lamp battery positive voltage circuit with a test lamp connected to a good ground.

Did the test lamp illuminate?

Go to Step 16

Go to Step 22

11
  1. Turn OFF the ignition.
  2. Disconnect the TCC/Brake switch harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the TCC/Brake switch ignition positive voltage circuit with a test lamp connected to a good ground.

Did the test lamp illuminate?

Go to Step 18

Go to Step 23

12
  1. Turn OFF the ignition.
  2. Disconnect the clutch pedal position (CPP) switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the CPP switch ignition positive voltage circuit with a test lamp connected to a good ground.

Did the test lamp illuminate?

Go to Step 20

Go to Step 24

13

Test the cruise control ON switch signal circuit for a open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 28

14

Test the cruise control Set/Coast signal circuit for a open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 28

15

Test the cruise control Resume/Accelerate signal circuit for a open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 28

16

Test the stop lamp switch signal circuit for a open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 17

17

Check the stop lamp switch for proper adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.

Is the stop lamp switch adjusted properly?

Go to Step 25

Go to Step 25

18

Test the TCC/Brake switch signal circuit for a open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 19

19

Check the TCC/Brake switch for proper adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.

Is the TCC/Brake switch adjusted properly?

Go to Step 26

Go to Step 26

20

Test the CPP switch signal circuit for a open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 35

Go to Step 27

21

Repair the open, high resistance or short to ground in the multifunction turn signal lever ignition positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 35

--

22

Repair the open, high resistance or short to ground in the stop lamp switch battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 35

--

23

Repair the open, high resistance or short to ground in the TCC/Brake switch battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 35

--

24

Repair the open, high resistance or short to ground in the CPP switch battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 35

--

25

Inspect for poor connections at the harness connector of the stop lamp 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 35

Go to Step 30

26

Inspect for poor connections at the harness connector of the TCC/Brake 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 35

Go to Step 31

27

Inspect for poor connections at the harness connector of the CPP 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 35

Go to Step 32

28

Inspect for poor connections at the harness connector of the multifunction turn signal lever. 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 35

Go to Step 33

29

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 35

Go to Step 34

30

Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 35

--

31

Replace the TCC/Brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 35

--

32

Replace the CPP switch. Refer to Clutch Pedal Position Switch Replacement in Clutch.

Did you complete the replacement?

Go to Step 35

--

33

Replace the multifunction turn signal lever. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?

Go to Step 35

--

34

Important: The PCM must be reprogrammed before replacement. Refer to Powertrain Control Module Programming .

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls.

Did you complete the replacement?

Go to Step 35

--

35

Operate the vehicle within the conditions for cruise control operation.

Does the cruise control system operate properly?

System OK

Go to Step 2