GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1998 🢒 Grand Prix 🢒 Body and Accessories 🢒 Cruise Control 🢒 Cruise Control Inoperative

Important: Complete the following steps in order to avoid misdiagnosis:

   • Inspect the brake lamps and the CHMSL lamps for correct operation.
        The brake signal input must be pulled low through CKT 17 or the cruise control will not operate correctly.
   • Inspect the throttle linkage for mechanical binding which may cause the system to malfunction.
   • Inspect for stored diagnostic trouble codes (DTCs). Refer to Engine Controls.
   • The PCM will inhibit the cruise control under the following conditions:
      - The vehicle speed is less than 40 km/h (25 mph).
      - The transaxle range switch indicates one of the following positions:
         • 
   • PARK
         • 
   • REVERSE
         • 
   • NEUTRAL
         • 
   • 1st gear
      - An over/under battery condition exists.
      - There is low engine RPM.
      - There is high engine RPM (fuel cut-off). Refer to Engine Controls.
Improper cruise control operation may be caused by a number of mechanical or electrical conditions. Complete the following steps in order to resolve any cruise control difficulties:
   • Inspect the cruise control wiring for bare or broken wires.
   • Inspect for loose or backed-out terminals.
   • Inspect for a properly adjusted cruise control cable. Refer to Cruise Control Cable Replacement or Cruise Control Cable Adjustment .
If preliminary inspections reveal no solution and the system is inoperative, refer to Cruise Control System Check .

Step

Action

Value(s)

Yes

No

1

Inspect the stoplamp fuse for an open.

Is the stoplamp fuse open?

--

Go to Step 2

Go to Step 3

2
  1. Replace a short to ground in CKT 140.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

3

Inspect the CRUISE fuse for an open.

Is the CRUISE fuse open?

--

Go to Step 4

Go to Step 5

4
  1. Repair a short to ground in CKT 739.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

5
  1. Set the OFF-ON-R/A switch to the OFF position.
  2. Disconnect the cruise control module.
  3. Turn the ignition switch to the RUN position.
  4. Connect a test lamp.
  5. Probe between the cruise control module connector terminal F and ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 17

6
  1. Connect a test lamp.
  2. Frontprobe between terminal F and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 7

Go to Step 18

7
  1. Set the OFF-ON-R/A switch to the ON position.
  2. Connect a test lamp.
  3. Frontprobe between terminal A and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 8

Go to Step 19

8
  1. Press and hold the SET CRUISE (Set/Coast) switch.
  2. Connect a test lamp.
  3. Frontprobe between terminal B and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 9

Go to Step 26

9
  1. Set and hold the OFF-ON-R/A switch to the R/A (Resume/Accelerate) position.
  2. Connect a test lamp.
  3. Frontprobe between terminal C and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 10

Go to Step 30

10
  1. Connect a test lamp.
  2. Frontprobe between terminal D and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 11

Go to Step 34

11
  1. Connect a test lamp.
  2. Frontprobe between terminal G and terminal E of the cruise control module connector.
  3. Press down the brake pedal.

Does the test lamp light?

--

Go to Step 12

Go to Step 45

12
  1. Connect a test lamp.
  2. Frontprobe between terminal B and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 13

Go to Step 48

13

Inspect CKT 84 for a short to B+.

Is there a short to B+ in CKT 84?

--

Go to Step 14

Go to Step 25

14
  1. Repair the short to B+ in CKT 84.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

15
  1. Connect a J 39200 DMM.
  2. Inspect CKT 87 for a short to B+.

Is there a short to B+ in CKT 87?

--

Go to Step 16

Go to Step 25

16
  1. Repair the short to B+ in CKT 87.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

17
  1. Repair the poor connection or open in CKT 739 between the cruise control module harness connector terminal F and S266.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

18
  1. Repair the poor connection or open in CKT 1650 between the cruise control module connector terminal E and G119.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

19

Inspect CKT 739 for a poor connection or open between the turn signal lever and S266.

Is there a poor connection or open in CKT 739?

--

Go to Step 20

Go to Step 21

20
  1. Repair the poor connection or open in CKT 739.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

21

Inspect CKT 397 for a short to ground.

Is there a short to ground in CKT 397?

--

Go to Step 22

Go to Step 23

22
  1. Repair the short in CKT 397.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

23

Inspect CKT 397 for a poor connection or open.

Is there a poor connection or open in CKT 397?

--

Go to Step 24

Go to Step 25

24
  1. Repair the poor connection or open in CKT 397.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

25
  1. Replace the turn signal lever. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column - Tilt.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

26

Inspect CKT 84 for a short to ground.

Is there a short to ground in CKT 84?

--

Go to Step 27

Go to Step 28

27
  1. Repair the short to ground in CKT 84.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

28

Inspect CKT 84 for a poor connection or open.

Is there a poor connection or open in CKT 84?

--

Go to Step 29

Go to Step 25

29
  1. Repair the poor connection or open in CKT 84.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

30
  • Inspect CKT 87 for a short to ground.

Is there a short to ground in CKT 87?

--

Go to Step 31

Go to Step 32

31
  1. Repair the short to ground in CKT 87.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

32

Inspect CKT 87 for a poor connection or open.

Is there a poor connection or open in CKT 87?

--

Go to Step 33

Go to Step 25

33
  1. Repair the poor connection or open in CKT 87.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

34
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the cruise control release switch.
  3. Turn the ignition switch to the ON position.
  4. Connect a test lamp.
  5. Frontprobe between the cruise control release switch connector terminal B and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 35

Go to Step 36

35
  1. Connect a jumper wire between the terminal A and terminal B of the cruise control release switch connector.
  2. Connect a test lamp.
  3. Frontprobe between the terminal D and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 38

Go to Step 42

36

Inspect CKT 739 between terminal B of the cruise control release switch connector and S266 for a poor connection or an open.

Is there a poor connection or open in CKT 739?

--

Go to Step 37

Go to Step 40

37
  1. Repair a poor connection or open in CKT 739.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

38

Inspect CKT 86 for a short to ground.

Is there a short to ground in CKT 86?

--

Go to Step 39

Go to Step 40

39
  1. Repair the short to ground in CKT 86.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

40

Inspect CKT 86 for a poor connection or open.

Is there a poor connection or open in CKT 86?

--

Go to Step 41

Go to Step 42

41
  1. Repair the poor connection or open in CKT 86.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

42

Inspect the cruise control release switch for correct alignment. Refer to Cruise Release Switch Adjustment .

Is the cruise control release switch correctly aligned?

--

Go to Step 43

Go to Step 44

43
  1. Replace the cruise control release switch. Refer to Cruise Control Release Switch Replacement .
  2. Inspect the system.

Is the repair complete?

--

System OK

--

44
  1. Align the cruise control release switch. Refer to Cruise Release Switch Adjustment .
  2. Inspect the system.

Is the repair complete?

--

System OK

--

45

Inspect the stop lamp switch for proper alignment. Refer to Cruise Release Switch Adjustment .

Is the stop lamp switch correctly aligned?

--

Go to Step 46

Go to Step 47

46
  1. Repair the open or the poor connection in CKT 17 between S205 and the cruise control module.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

47
  1. Align the stop lamp switch. Refer to Cruise Release Switch Adjustment .
  2. Inspect the system.

Is the repair complete?

--

System OK

--

48
  1. Connect a test lamp.
  2. Frontprobe between the terminal C and terminal E of the cruise control module connector.

Does the test lamp light?

--

Go to Step 15

Go to Step 49

49
  1. Set the parking brake.
  2. Raise the drive wheels.
  3. Measure the voltage between the cruise control module connector between terminal K and ground.
  4. Rotate the drive wheels by hand in order to observe the display of the J 39200 DMM.

Is the voltage within the specified range?

0-5 V

Go to Step 50

Go to Step 51

50
  1. Set the ignition switch to the OFF position.
  2. Inspect CKT 83 for a poor connection or an open between the PCM and the cruise control module.
  3. Reinstall the cruise control module connector.
  4. Connect a scan tool to the data link connector (DLC).
  5. Use the scan tool in order to command the SMCC to ALLOW cruise.
  6. Clear any diagnostic trouble codes (DTCs).
  7. Monitor the SMCC INHIBITED display on the scan tool.
  8. Operate the vehicle in the cruise control mode.

Is the SMCC INHIBITED at the scan tool?

--

Go to Step 54

Go to Step 56

51

Inspect CKT 389 for a poor connection or an open between the cruise control module connector and the powertrain control module (PCM) connector C1 terminal 55.

Is there a poor connection or open in CKT 389?

--

Go to Step 52

Go to Step 53

52
  1. Repair the poor connection or open in CKT 389.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

53
  1. Service the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls - 3.1L or to Powertrain Control Module Replacement/Programming in Engine Controls - 3.8L.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

54
  1. Connect a Scan Tool .
  2. Use the scan tool in order to monitor the following parameters:
    3. • The vehicle speed sensor (VSS) is between 40-160 km/h (25-100 mph).
    • The transmission range is the 2nd, 3rd or 4th gear.
    • The system voltage is between 9-17 volts.
    • The engine speed is 500-5400 RPM.

Are the above parameters within range?

--

Go to Step 53

Go to Step 55

55
  1. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.1L or to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.8L.
  2. Inspect the system.

Is the repair complete?

--

System OK

--

56
  1. Set the ignition switch to the OFF position.
  2. Set the ignition switch to the RUN position.
  3. Connect a scan tool.
  4. Clear any DTCs.
  5. Select MODE 4 DIAGNOSTICS on the scan tool.
  6. Use the scan tool in order to command the SMCC to ALLOW cruise.
  7. Connect a test lamp.
  8. Frontprobe between the terminal H and terminal F on the cruise control connector.

Does the test lamp light?

--

Go to Step 57

Go to Step 58

57
  1. Replace the cruise control module. Refer to Cruise Control Module Replacement .
  2. Inspect the system.

Is the repair complete?

--

System OK

--

58

Inspect CKT 83 for a short to B+.

Is there a short in CKT 83?

--

Go to Step 59

Go to Step 53

59
  1. Repair the short in CKT 83.
  2. Inspect the system.

Is the repair complete?

--

System OK

--