GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 CTS - RHD 🢒 Body and 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:

    • Inspect for proper operation of the brake lamps. Refer to Exterior Lighting Systems Description and Operation in Wiring Systems.
    • Inspect for proper adjustment of the TCC/cruise control release switch, if equipped with automatic Transmission. Refer to Torque Converter Clutch/Cruise Control Release Switch Adjustment in Automatic Transmission - 5L40-E.
    • Inspect for proper operation of the clutch system, if equipped with manual transmission. Refer to Clutch System Description and Operation in Clutch.
    • Rotate the steering wheel to both steering stops while testing the steering wheel control switches. This will eliminate the possibility of a internally open or shorted inflatable restraint steering wheel module coil.

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: Cruise Control Connector End Views

1

Did you perform the Cruise Control Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2
  1. Install a scan tool.
  2. Turn the ignition ON, 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 TAC Data list:
    5. • Cruise On/Off Switch
    • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch

Do all of the parameters listed above display Off?

Go to Step 3

Go to Step 10

3
  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 4

Go to Step 11

4
  1. With the scan tool, observe the Cruise Set/Coast Switch parameter.
  2. press the "-" switch.

Does the Cruise Set/Coast Switch parameter display On?

Go to Step 5

Go to Step 31

5
  1. With the scan tool, observe the Cruise Resume/Accel Switch parameter.
  2. press the "+" switch.

Does the Cruise Resume/Accel Switch parameter display On?

Go to Step 6

Go to Step 31

6

With the scan tool, observe the Extended Travel Brake Switch parameter in the TAC Data list.

Does the Extended Travel Brake Switch parameter display Applied?

Go to Step 15

Go to Step 7

7
  1. With the scan tool, observe the Extended Travel Brake Switch parameter.
  2. Depress the brake pedal.

Does the Extended Travel Brake Switch parameter display Applied?

Go to Step 8

Go to Step 14

8

With the scan tool, observe the Cruise Release Brake Pedal Switch parameter in the TAC Data list.

Does the Cruise Release Brake Pedal Switch parameter display Applied?

Go to Step 18

Go to Step 9

9
  1. With the scan tool, observe the Cruise Release Brake Pedal Switch parameter.
  2. Press the brake pedal.

Does the Cruise Release Brake Pedal Switch parameter display Applied?

Go to Diagnostic Aids

Go to Step 17

10
  1. Turn the ignition OFF.
  2. Disconnect the cruise switch.
  3. Turn the ignition ON, with the engine OFF.
  4. Observe the Cruise On/Off Switch parameter in the TAC Data list.

Does the Cruise On/Off Switch parameter display Off?

Go to Step 26

Go to Step 20

11
  1. Turn the ignition OFF.
  2. Disconnect cruise switch.
  3. Turn the ignition ON, with the engine OFF.
  4. Connect a test lamp between the ignition positive voltage circuit and a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 30

12

Connect a test lamp between the ignition positive voltage circuit and the ground circuit of the cruise switch.

Does the test lamp illuminate?

Go to Step 13

Go to Step 29

13
  1. Connect a 3 ampere fused jumper between the ignition positive voltage circuit and the cruise control 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 26

Go to Step 21

14
  1. Turn the ignition OFF.
  2. Disconnect the TCC/cruise control release switch.
  3. Turn the ignition ON, with the engine OFF.
  4. With the scan tool, observe the Extended Travel Brake Switch parameter.

Does the Extended Travel Brake Switch parameter display Applied?

Go to Step 27

Go to Step 22

15
  1. Turn the ignition OFF.
  2. Disconnect the TCC/cruise control release switch.
  3. Connect a 3 ampere fused jumper between the ignition positive voltage circuit and the extended travel brake switch signal circuit.
  4. Turn the ignition ON, with the engine OFF.
  5. With the scan tool, observe the Extended Travel Brake Switch parameter.

Does the Extended Travel Brake Switch parameter display Applied?

Go to Step 16

Go to Step 27

16
  1. Connect a 3 ampere fused jumper between the extended travel brake switch signal circuit and battery voltage.
  2. With the scan tool, observe the Extended Travel Brake Switch parameter.

Does the Extended Travel Brake Switch parameter display Applied?

Go to Step 23

Go to Step 30

17
  1. Turn the ignition OFF.
  2. Disconnect the TCC/cruise control release switch.
  3. Turn the ignition ON, with the engine OFF.
  4. With the scan tool, observe the Cruise Release Brake Pedal Switch parameter.

Does the Cruise Release Brake Pedal Switch parameter display Applied?

Go to Step 27

Go to Step 24

18
  1. Turn the ignition OFF.
  2. Disconnect the TCC/cruise control release switch.
  3. Turn the ignition ON, with the engine OFF.
  4. Connect a 3 ampere fused jumper between the ignition positive voltage circuit and the TCC brake switch/cruise control release switch signal circuit.
  5. With the scan tool, observe the Cruise Release Brake Pedal Switch parameter.

Does the Cruise Release Brake Pedal Switch parameter display Applied?

Go to Step 19

Go to Step 27

19
  1. Connect a 3 ampere fused jumper between the TCC brake switch/cruise control release switch signal circuit and battery voltage.
  2. With the scan tool, observe the Cruise Release Brake Pedal Switch parameter.

Does the Cruise Release Brake Pedal Switch parameter display Applied?

Go to Step 25

Go to Step 30

20

Test the cruise control 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 34

Go to Step 28

21

Test the cruise control switch signal circuit for an open, for a short to ground, 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 34

Go to Step 28

22

Test the extended travel brake 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 34

Go to Step 28

23

Test the extended travel brake switch signal circuit for an open, for a short to ground, 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 34

Go to Step 28

24

Test the cruise release brake pedal 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 34

Go to Step 28

25

Test the cruise release brake pedal switch signal circuit for an open, for a short to ground, or high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 34

Go to Step 27

26

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 34

Go to Step 31

27

Inspect for poor connections at the harness connector of the stoplamp 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 34

Go to Step 32

28

Inspect for poor connections at the harness connector of the ECM. 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 34

Go to Step 33

29

Repair the open or the high resistance in the ground circuit of the cruise switch. Refer to Wiring Repairs Wiring Systems.

Did you complete the repair?

Go to Step 34

--

30

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

Did you complete the repair?

Go to Step 34

--

31

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 34

--

32

Replace the TCC/cruise control release switch. Refer to Torque Converter Clutch/Cruise Control Release Switch Replacement in Automatic Transmission -- 5L40-E.

Did you complete the replacement?

Go to Step 34

--

33

Important: Program the replacement ECM.

Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 2.6L and 3.2L..

Did you complete the replacement?

Go to Step 34

--

34
  1. Enable the inflatable restraint steering wheel module. Refer to SIR Disabling and Enabling in SIR
  2. Operate the vehicle with in the conditions for cruise control operation.

Does the cruise control system operate properly?

System OK

Go to Step 2